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International Journal of Food and Biosystems Engineering ISSN: 2408-0675

INTERNATIONAL JOURNAL

OF FOOD

and

BIOSYSTEMS ENGINEERING

Volume 4, Number 1, June 2017

Supported by

Technological Educational Institute of Thessaly, The Technological Research Center of Thessally

and the

Laboratory of the Food and Biosystems Engineering of TEI of Thessaly

website: http://www.fabe.gr/en/journal

http://www.fabe.gr/en/journal


Publication information:

International Journal of Food and Biosystems Engineering, ISSN 2408-0675 is published every two

months as an electronic and hard copy Journal by the laboratory of Foods and Biosystems Engineering

which is incorporated in the structure of Biosystems Engineering Dept. of the School of Agricultural

Technology of Technological Educational Institute (TEI) of Thessaly. The laboratory is located at TEI

of Thessaly at peripheral road Larissa-Trikala, 411 10, Larissa, Greece.

Aims and Scope:

The International Journal of Food and Biosystems Engineering has broad and scientifically interesting

topics on: ‘Environmental Sustainability and innovation of Food and Biosystems Engineering in an

“Ever Changing World”. The journal offering a platform where knowledge, innovative ideas,

experiences and research achievements of people involved in the field of Food and Biosystems

Engineering found a step of expression and dissemination. International Journal of Food and

Biosystems Engineering is a professional Academic journal particularly emphasizes new research

results and innovations in topics such as:

Advances in Food Process Engineering.

Engineering of Novel Food Process.

Food Product Engineering and Functional Foods.

Food and Agricultural Waste & Byproducts.

Advances in Food Packaging and Preservation.

Modeling and Control of Food Process.

C.F.D. applications in Food Engineering.

Novel Aspects of Food Safety and Quality

Nano and microencapsulation in Food and Agriculture.

Engineering and Mechanical Properties of Food.

Sustainability aspects in food and agricultural engineering.

Extraction Technology for natural antioxidants and Phytochemical.

Industrial Fermentations and Biotechnology.

Advanced Greenhouse Technologies.

Precision Agriculture and Variable Rate Irrigation.

Water and Wastewater Management and Irrigation Engineering.

Novel Bioremediation Technologies

Automation –Robotics and Geo-information novelty in Bio-systems Engineering.

Multi Criteria Decision Analysis, Remote Sensing, GIS and Fuzzy Logic Modeling.

Biosensors Engineering and Applications.

Wastewater and Sludge Reuse from Food, Agricultural and other Industries.

Pollution of natural resources Ecotoxicology.

Biomass, Photovoltaic (solar cell) and Aeolian (Wind) Energy engineering

Editorial Board Members:

Prof., A Gálvez (Spain) Assistant Prof., E. Hatzidimitriou (Greece)

Associate Prof., Adrian Asanica (Romania) Dr. Efi Alexopoulou (Greece)

Associate Prof., Aicha Nancib (Algeria) Assoc Prof., Esra Capanoglu (Turkey)

Dr. Aleksandra Djukić-Vuković (Serbia) Dr. Estela de Oliveira Nunes (Brazil)

Prof., Alexander Jaeger (Austria) Prof., Fabio Marcelo Breunig (Brazil)

Prof., Alexandrina Sîrbu (Romania) Dr. Fernando D. Ramos (Argentina)

Prof., Ali Zazoua (Algeria) Dr. Ferruh Erdogdu (Turkey)

Prof., Alina Catrinel Ion (Romania) Prof., Figen Ertekin (Turkey)

Associate Prof., Alina Kunicka-Styczyńska (Poland) Prof., Francis Butler (Ireland)

Dr. Amin Mousavi Khaneghah (Brazil;Iran) Assist. Prof., Francisco Javier Deive (Spain)

Dr. Ana B. Baranda (Spain) Prof., Gil Fraqueza (Portugal)

Dr. Ana María Diez Pascual (Spain) Prof., Gustavo V. Barbosa-Cánovas (USA)

Dr. Ana Sanches Silva (Portugal) Prof., Idlimam Ali (Morocco)

Prof., Anand Y. Joshi (India) Prof., Ingrid Bauman (Croatia)

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Emeritus Prof., Andree Voilley (France) Dr. Iuliana Diana Barbulescu (Romania)

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Dr. Angelo Algieri (Italy) Dr. Jorge Welti-Chanes (México)

Dr., Annamaria Costa (Italy) Dr. K. Alagusundaram (India)


Dr. Artur Wiktor (Poland) Prof., Keshavan Niranjan (UK)

Associate Prof., Ayse Handan Baysal (Turkey) Assistant Prof., K. Dermentzis (Greece)

Prof., B.H. Chen (Taiwan) Prof., Laura Piazza (Italy)

Prof., Baghdad Ouddane (France) Prof., M. Chandrasekaran (Saudi Arabia)

Dr. Benmeziane Farida (Algeria ) Prof., Marco Dalla Rosa (Italy)

Prof., Bharathi Raja (India) Prof., Marek Kowalczuk (UK)

Prof., Branka Levaj (Croatia) Prof., Maria Turtoi (Romania)

Prof., Brett Pletschke (South Africa) Dr. Mihaela Βegea (Romania)

Prof., Cornelia Vasile (Romania) Associate Prof., Minh Nguyen (Australia)

Prof., Célia Quintas (Portugal) Prof., Miriam Hubinger (Brazil)

Associate Prof., Celile O. Dolekoglu (Turkey) Prof., Miroljub Barać ( Serbia)

Assistant Prof., Cheima Fersi (Tunisia) Prof., Muhammad Subhan Qureshi (Pakistan)

Prof., Chuan-He Tang (China) Dr. Navin K Rastogi (India)

Prof., Constantina Tzia (Greece) Dr. Ourania Gouseti (UK)

Prof., Constantine Sflomos (Greece) Assoc. Prof., Olga Gortzi (Greece)

Prof., Costas Stathopoulos (UK) Prof., Paula Pires-Cabral (Portugal)

Dr. Cristina Castillo (Spain) Prof., Ruta Galoburda (Latvia)

Prof., Cristina L.M. Silva (Portugal) Dr. Sara Canas (Portugal)

Dr. Dagbjorn Skipnes (Norway) Prof., Stavros Yanniotis (Greece)

Assoc. Prof., Dainius Steponavičius (Lithuania) Prof., Stefanos Zaoutsos (Greece)

Prof., Dan Scarpete (Romania) Prof .,Tawfik Benabdallah (Algeria)

Dr. Daniel Hill (Spain) Dr. Ursula A. Gonzales-Barron (Portugal)

Assistant Prof., Daniel Abugri (USA) Prof., V. Aslıhan Nasır (Turkey)

Assistant Prof., Deborah Panepinto (Italy) Dr. Veronica Chedea (Romania)

Prof. Dimitrios Fessas (Italy) Assoc. Prof., Yacoub Idriss Halawlaw (Chad)

Dr. Douglas Wilson (UK) Prof., Yen-Con Hung (USA)

Prof., Dritan Topi (Albania) Assoc. Prof., Yesim Ekinci (Turkey)

Assistant Prof., Dubravka Novotni (Croatia) Emeritus Prof., Zeki Berk (Israel)

Associate Prof., Oguz Gursoy (Turkey)

Manuscripts and correspondence are invited for publication. You can submit your paper via we

submission or e-mail to: [email protected]. Submission guidelines and web submission system are

available at: http://www.fabe.gr/en/journal

Editorial office:

Editor: Associate Professor Konstantinos Petrotos

Editorial team members: Dr. Stefanos Leontopoulos, Sotiria Tsilfoglou, Maria Papakosta, Zoi

Papathanasiou, Marios Chalaris, Fani Karkanta, Tatiana Androulaki,

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TEI of Thessaly, Periferial road Larissa-Trikala, 411 10, Larissa, Greece

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Technological Educational Institute of Thessaly

(TEI of Thessaly),

Perifereiaki Odos Larissa-Trikala,

Larissa, TK 41110, Greece

mailto:[email protected]

http://www.fabe.gr/en/journal




Contents

Research Papers

1 Greenhouses for Food Production and the Environment

Abdeen Mustafa Omer

34 Strategies for the Prevention and (Subsequent) Use of Food Waste from Hospitality and

Restaurant Industries

Alexander Jager, Douglas Vaught, Klaus Krennhuber, Paul Kuttner, Dominik Lehner

43 Quality Attributes of Apple Slices Coated with Mixed Hydrogel for Shelf Life Extension

Sibel Uzuner, Guler Bengusu Tezel, Gulsun Akdemir Evrendilek

50 Commercial In-line or Continuous Microwave Processing of Pumpable Shelf-Stable

Agricultural Products

David L. Parrott

57 Improvement of the Techno-Functional Properties of Pea Proteins by Microfluidization

Oliete, B., Potin, F., Cases, E., Saurel, R.

69 Evaluation of Quality and Shelf-life of Pasteurized Goat Milk Produced Under Smallholder

Condition in a Farmer Group

Yuni Suranindyah, F.Trisakti Haryadi, Diah Triwidayati

77 Mercury Level in Tissues of European Badger (Meles meles L.) from Eastern Slavonia,

Croatia

Sinisa Ozimec, Svjetlana Milin Radic, Tihomir Florijancic, Ivica Boskovic, Andrea Gross-

Boskovic

82 Removal of Tetracycline by Candida utilis-Polyacrylonitrile Biocomposites

Feray Kip, Unsal Acikel

91 Investigation of Acid Orange 74 Dye Adsorption with Anaerob Activated Sludge

Gamze Topal Canbaz1, Unsal Acikel, Yesim Sag Acikel

97 Impact of Pulsed Electric Fields and Heat Treatment on Quality of Licorice Drink: A

Comparative Study

Sibel Uzuner, Gulsun Akdemir Evrendilek

International Journal of Food

and

Biosystems Engineering

Volume 4, Number 1, June 2017

International Journal of Food and Biosystems Engineering, June, 2017 Vol 4(1) 1-33

Greenhouses for Food Production and theEnvironment

Abdeen Mustafa Omer∗

Energy Research Institute (ERI), Forest Road West, Nottingham NG7 4EU, UK

Abstract

A greenhouse is essentially an enclosed structure, which traps the short wave-length solar radiation and stores the long wavelength thermal radiation tocreate a favourable microclimate for higher productivity. The sun’s radiationincident on the greenhouse has two parts: direct radiation and an associateddiffuse sky radiation. The diffuse part is not focused by the lenses and goesright through Frensel lenses onto the surface of the absorbers. This energy isabsorbed and transformed into heat, which is then transported via the liquidmedium in copper pipes to the water (heat) storage tanks or, if used, openfish tanks. In this way, an optimal temperature for both plant cultivation andfish production can be maintained. Stable plant growth conditions are light,temperature and air humidity. Light for the photosynthesis of plants comes fromthe diffuse radiation, which is without substantial fluctuations and variationthroughout most of the day. The air temperature inside the greenhouse is one ofthe factors that have an influence on the precocity of production. The selectivecollector acts in a more perceptible way on extreme air temperatures inside thegreenhouse. Hence, the system makes it possible to avoid the excessive deviationof the temperature inside the greenhouse and provides a favourable microclimatefor the precocity of the culture. Sediment and some associated water from thesediment traps are used as organic fertiliser for the plant cultivation. Thepresent trend in greenhouse cultivation is to extend the crop production seasonin order to maximise use of the equipment and increase annual productivityand profitability. However, in many Mediterranean greenhouses, such practicesare limited because the improper cooling methods (mainly natural or forcedventilation) used do not provide the desired micro-climatic condition duringthe summer of a composite climate. Also, some of these greenhouses havebeen built where the meteorological conditions require some heating during thewinter, particularly at night. The worst scenario is during the winter monthswhen relatively large difference in temperature between day and night occurs.However, overheating of the greenhouse during the day is common, even inwinter, requiring ventilation of the structure. Hence, several techniques have

∗Corresponding author e-mail:[email protected]

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been proposed for the storage of the solar energy received by the greenhouseduring the day and its use to heat the structure at night. Reviews of suchtechniques are presented in this chapter. Air or water can be used for heattransport. The circulating water is heated during the day via two processes.The water absorbs part of the infrared radiation of the solar spectrum. Since thewater is transparent in the visible region, they do not compete with the plantsthat need it. Alternatively, the water exchanges heat with the greenhouse airthrough the walls. At night, if the greenhouse temperature goes down belowa specified value, the water begins to circulate acting as heat transfer surfacesheating the air in the greenhouse. This chapter describes various designs of lowenergy greenhouses. It also, outlines the effect of dense urban building nature onenergy consumption, and its contribution to climate change. Measures, whichwould help to save energy in greenhouses, are also presented. It also enabledthe minimisation of temperature variation and, hence avoided the hazard of anysudden climatic change inside the greenhouse.

Keywords: Greenhouse environment, energy efficient comfort, ventilation,humidity, sustainable environmental impact

Globally, buildings are responsible forapproximately 40% of the total worldannual energy consumption [1]. Most

of this energy is for the provision of lighting,heating, cooling, and air conditioning. Increas-ing awareness of the environmental impact ofCO2 and NOx emissions and CFCs triggered arenewed interest in environmentally friendlycooling, and heating technologies. Under the1997 Montreal Protocol, governments agreedto phase out chemicals used as refrigerantsthat have the potential to destroy stratosphericozone. It was therefore considered desirable toreduce energy consumption and decrease therate of depletion of world energy reserves andpollution of the environment.

One way of reducing building energy con-sumption is to design building, which is moreeconomical in their use of energy for heating,lighting, cooling, ventilation and hot water sup-ply. Passive measures, particularly natural orhybrid ventilation rather than air-conditioning,can dramatically reduce primary energy con-sumption [2]. However, exploitation of re-newable energy in buildings and agriculturalgreenhouses can, also, significantly contribute

towards reducing dependency on fossil fuels.Therefore, promoting innovative renewable ap-plications and reinforcing the renewable energymarket will contribute to preservation of theecosystem by reducing emissions at local andglobal levels. This will also contribute to theamelioration of environmental conditions byreplacing conventional fuels with renewableenergies that produce no air pollution or green-house gases.

The provision of good indoor environmen-tal quality while achieving energy and costefficient operation of the heating, ventilatingand air-conditioning (HVAC) plants in build-ings represents a multi variant problem. Thecomfort of building occupants is dependenton many environmental parameters includingair speed, temperature, relative humidity andquality in addition to lighting and noise. Theoverall objective is to provide a high level ofbuilding performance (BP), which can be de-fined as indoor environmental quality (IEQ),energy efficiency (EE) and cost efficiency (CE).

• Indoor environmental quality is the per-ceived condition of comfort that buildingoccupants experience due to the physical

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and psychological conditions to whichthey are exposed by their surroundings.The main physical parameters affectingIEQ are air speed, temperature, relativehumidity and quality.

• Energy efficiency is related to the provi-sion of the desired environmental condi-tions while consuming the minimal quan-tity of energy.

• Cost efficiency is the financial expendi-ture on energy relative to the level ofenvironmental comfort and productivitythat the building occupants attained. Theoverall cost efficiency can be improvedby improving the indoor environmentalquality and the energy efficiency of abuilding.

An approach is needed to integrate renew-able energies in a way to meet high buildingperformance. However, because renewable en-ergy sources are stochastic and geographicallydiffuse, their ability to match demand is de-termined by adoption of one of the followingtwo approaches [2]: the utilisation of a capturearea greater than that occupied by the com-munity to be supplied, or the reduction of thecommunity’s energy demands to a level com-mensurate with the locally available renewableresources.

For a northern European climate, which ischaracterised by an average annual solar irradi-ance of 150 Wm−2, the mean power productionfrom a photovoltaic component of 13% conver-sion efficiency is approximately 20 Wm−2. Foran average wind speed of 5 ms−1, the powerproduced by a micro wind turbine will be ofa similar order of magnitude, though with adifferent profile shape. In the UK, for example,a typical office building will have a demandin the order of 300 kWhm−2yr−1. This trans-lates into approximately 50 Wm−2 of faÃgade,which is twice as much as the available renew-able energies [3]. Thus, the aim is to utiliseenergy efficiency measures in order to reducethe overall energy consumption and adjust thedemand profiles to be met by renewable en-

ergies. For instance, this approach can be ap-plied to greenhouses, which use solar energyto provide indoor environmental quality. Thegreenhouse effect is one result of the differingproperties of heat radiation when it is gener-ated at different temperatures. Objects insidethe greenhouse, or any other building, such asplants, re-radiate the heat or absorb it. Becausethe objects inside the greenhouse are at a lowertemperature than the sun, the re-radiated heatis of longer wavelengths, and cannot penetratethe glass. This re-radiated heat is trapped andcauses the temperature inside the greenhouseto rise. Note that the atmosphere surroundingthe earth, also, behaves as a large greenhousearound the world. Changes to the gases in theatmosphere, such as increased carbon dioxidecontent from the burning of fossil fuels, canact like a layer of glass and reduce the quantityof heat that the planet earth would otherwiseradiate back into space. This particular green-house effect, therefore, contributes to globalwarming. The application of greenhouses forplants growth can be considered one of themeasures in the success of solving this prob-lem. Maximising the efficiency gained from agreenhouse can be achieved using various ap-proaches, employing different techniques thatcould be applied at the design, constructionand operational stages. The development ofgreenhouses could be a solution to farmingindustry and food security.

The move towards a de-carbonised world,driven partly by climate science and partly bythe business opportunities it offers, will needthe promotion of environmentally friendly al-ternatives, if an acceptable stabilisation level ofatmospheric carbon dioxide is to be achieved.This requires the harnessing and use of natu-ral resources that produce no air pollution orgreenhouse gases and provides comfortable co-existence of human, livestock, and plants. Thisstudy reviews the energy-using technologiesbased on natural resources, which are availableto and applicable in the farming industry. Inte-gral concept for buildings with both excellentindoor environment control and sustainable en-vironmental impact are reported in the present

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communication.Techniques considered are hybrid (con-

trolled natural and mechanical) ventilation in-cluding night ventilation, thermo-active build-ing mass systems with free cooling in a coolingtower, and air intake via ground heat exchang-ers. Special emphasis is put on ventilation con-cepts utilising ambient energy from air groundand other renewable energy sources, and onthe interaction with heating and cooling. Ithas been observed that for both residential andoffice buildings, the electricity demand of ven-tilation systems is related to the overall de-mand of the building and the potential of pho-tovoltaic systems and advanced co-generationunits. The focus of the world’s attention onenvironmental issues in recent years has stimu-lated response in many countries, which haveled to a closer examination of energy conser-vation strategies for conventional fossil fuels.One way of reducing building energy consump-tion is to design buildings, which are moreeconomical in their use of energy for heating,lighting, cooling, ventilation and hot water sup-ply.

Passive measures, particularly natural orhybrid ventilation rather than air-conditioning,can dramatically reduce primary energy con-sumption. However, exploitation of renewableenergy in buildings and agricultural green-houses can, also, significantly contribute to-wards reducing dependency on fossil fuels.

The main advantages of solar greenhouseare summarised as follows:

• In the climatic conditions of Europe, thecollector system equipped with linearraster lenses is able to absorb, on aver-age, 12% of the total incoming global so-lar energy on the collector and convertthis energy into heat at a temperature ofbetween 30 to −50 ◦C. The system, there-fore, consumes approximately 50% lessenergy for heating purposes than woulda traditional normal greenhouse.

• The system provides suitable, perhapsideal, conditions for the cultivation ofhigh quality vegetables, and even during

periods of maximum solar energy absorp-tion on the collectors, there still remainssufficient light for good vegetable growthunder the area of the collectors.

• Due to the almost continuous high hu-midity levels and to the applied nutrientsolution being rich in organic matter andmicroorganisms, organic matter is hardlymineralising in the soil, hence, does notdegrade in patches. On the contrary, or-ganic matter content in the soil increasedduring cultivation.

• In comparison with a traditional green-house, the system does not overheat in-side. Therefore, less ventilation is neces-sary, which brings the benefits of smallerlosses of water. Furthermore, the sys-tem saves energy, allows the efficient re-cycling of water and nutrients, and pro-vides suitable growth conditions with asmaller range of extreme humidity, tem-perature and light allowing the cultivatedplants to face less stress and have a higherquality.

• Due to the relatively low temperature inthe greenhouse, additional heating mightbe required. Therefore, vegetables willadapt to low radiation levels, and lowtemperatures and, consequently, qualityis preserved even during failure of con-trol system.

This study describes various designs of lowenergy buildings. It also, outline the effect ofdense urban building nature on energy con-sumption, the problems related to inadequateventilation in buildings, and its contribution toclimate change. Measures, which would helpto save energy in buildings, are also presented.

I. Indoors Environment

The heating or cooling of a space to maintainthermal comfort is a highly energy intensiveprocess accounting for as much as 60-70% oftotal energy use in non-industrial buildings.

4


Of this, approximately 30-50% is lost throughventilation and air infiltration.

However, estimation of energy impact ofventilation relies on detailed knowledge aboutair change rate and the difference in en-thalpy between the incoming and outgoing airstreams. In practice, this is a difficult exerciseto undertake since there is much uncertaintyabout the value of these parameters [4]. As aresult, a suitable datum from which strategicplanning for improving the energy efficiencyof ventilation can be developed has proved dif-ficult to establish [4]. Efforts to overcome thesedifficulties are progressing in the following twoways:

• Identifying ventilation rates in a repre-sentative cross section of buildings.

• The energy impact of air change in bothcommercial and domestic buildings.

In addition to conditioning energy, the fanenergy needed to provide mechanical ventila-tion can make a significant further contributionto energy demand. Much depends on the effi-ciency of design, both in relation to the perfor-mance of fans themselves and to the resistanceto flow arising from the associated ductwork.

The building sector is an important part ofthe energy picture. Note that the major func-tion of buildings is to provide an acceptable in-door environment, which allows occupants tocarry out various activities. Hence, the purposebehind this energy consumption is to providea variety of building services, which includeweather protection, storage, communications,thermal comfort, facilities of daily living, aes-thetics, work environment, etc.

However, the three main energy-relatedbuilding services are space conditioning (forthermal comfort), lighting (for visual com-fort), and ventilation (for indoor air quality).Pollution-free environments are a practical im-possibility. Therefore, it is often useful todifferentiate between unavoidable pollutantsover which little source control is possible, andavoidable pollutants for which control is possi-ble.

Unavoidable pollutants are primarily thoseemitted by metabolism and those arising fromthe essential activities of occupants. ’Wholebuilding’ ventilation usually provides an ef-fective measure to deal with the unavoidableemissions, whereas ’source control’ is the pre-ferred, and sometimes only practical, methodto address avoidable pollutant sources [5].

Hence, achieving optimum indoor air qual-ity relies on an integrated approach to the re-moval and control of pollutants using engineer-ing judgment based on source control, filtra-tion, and ventilation. Regardless of the kindof building involved, good indoor air qual-ity requires attention to both source controland ventilation. While there are sources com-mon to many kinds of buildings, buildingsfocusing on renewable energy may have someunique sources and, therefore, may require spe-cial attention [5]. In smaller (i.e., house size)buildings, renewable sources are already theprimary mechanism for providing ventilation.Infiltration and natural ventilation are the pre-dominant mechanisms for providing residen-tial ventilation for these smaller buildings.

Ventilation is the building service most as-sociated with controlling the indoor air qualityto provide a healthy and comfortable environ-ment. In large buildings ventilation is normallysupplied through mechanical systems, but insmaller ones, such as single-family homes, itis principally supplied by leakage through thebuilding envelope, i.e., infiltration, which isa renewable resource, albeit unintendedly so.Ventilation can be defined as the process bywhich clean air is provided to a space. It isneeded to meet the metabolic requirements ofoccupants and to dilute and remove pollutantsemitted within a space. Usually, ventilation airmust be conditioned by heating or cooling inorder to maintain thermal comfort and, hence,becomes an energy liability.

Indeed, ventilation energy requirementscan exceed 50% of the conditioning load insome spaces [5]. Thus, excessive or uncon-trolled ventilation can be a major contributorto energy costs and global pollution. There-fore, in terms of cost, energy, and pollution,

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efficient ventilation is essential. On the otherhand, inadequate ventilation can cause comfortor health problems for the occupants.

Good indoor air quality may be defined asair, which is free of pollutants that cause ir-ritation, discomfort or ill health to occupants[6]. Since long time is spent inside buildings,considerable effort has focused on developingmethods to achieve an optimum indoor envi-ronment. An almost limitless number of pol-lutants may be present in a space, of whichmany are at virtually immeasurably low con-centrations and have largely unknown toxico-logical effects [6]. The task of identifying andassessing the risk of individual pollutants has

become a major research activity [e.g., 5, 6 and7].

In reality, a perfectly pollutants-free en-vironment is unlikely to be attained. Somepollutants can be tolerated at low concentra-tions, while irritation and odour often providean early warning of deteriorating conditions.Health related air quality standards are typ-ically based on risk assessment and are ei-ther specified in terms of maximum-permittedconcentrations or a maximum allowed dose.Higher concentrations of pollutants are nor-mally permitted for short-term exposure thanare allowed for long-term exposure [7].

Ventilation is essential for securing a goodindoor air quality, but, as explained earlier, canhave a dominating influence on energy con-sumption in buildings. Air quality problemsare more likely to occur if air supply is re-stricted. Probably a ventilation rate averaging7 l/s.p represents a minimum acceptable ratefor normal odour and comfort requirements inoffice type buildings [8].

Diminishing returns are likely to be experi-enced at rates significantly above 10 l/s.p [8].If air quality problems still persist, the cause islikely to be poor outdoor air quality (e.g., theentrainment of outdoor traffic fumes), poor air

distribution or the excessive release of avoid-able pollutants into space.

However, the energy efficiency of ventila-tion can be improved by introducing exhaustair heat recovery, ground pre-heating, demandcontrolled ventilation, displacement ventilationand passive cooling [9]. In each case, a verycareful analysis is necessary to ensure thatthe anticipated savings are actually achievable.Also, it is essential to differentiate betweenavoidable and unavoidable pollutant emissions.Achieving energy efficiency and optimum In-door Air Quality (IAQ) depends on minimisingthe emission of avoidable pollutants. Pollu-

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tants inside greenhouses are derived from bothindoor and outdoor contaminant sources, asillustrated in Figure 1.

Each of these tends to impose different re-quirements on the control strategies needed tosecure good health and comfort conditions.

II. Achieving Energy Efficiency

Ventilation

A recent review of the International EnergyAgency [10] concludes that the thermal in-sulation characteristics of buildings improve;ventilation and air movement is expected tobecome the dominant heating and cooling lossmechanism in buildings of the next century.Poor air quality in buildings sometimes mani-fests itself; refer to a range of symptoms that anoccupant can experience while present in thebuilding. Typical symptoms include lethargy,headaches, lack of concentration, runny nose,dry throat and eye and skin irritation [10].Other examples of sick building syndromehave been associated with the presence ofspecific pollutants, such as outdoor fumesentering through air intakes [11]. Improvedventilation is one way of tackling the problem.Many standards are being introduced to en-sure the adequacy and efficiency of ventilation.However, to be effective, standards need toaddress the minimum requirements of com-fort, operational performance, air tightness,provision for maintenance and durability [11].Also, various methods have been introduced toimprove the energy performance of ventilation.These include:

Thermal RecoveryRecovery of thermal energy from the exhaustair stream is possible by means of air-to-airheat recovery systems or heat pumps. In the-ory, such methods can recover as much as 70%of the waste heat [12]. While these methodsare exceedingly popular, their full potentialis, often, not achieved. This is because build-ings or ductwork are often excessively leakyand, hence, additional electrical energy load isneeded. To be successful, the designer must

integrate such ventilation design with that ofthe building itself and be thoroughly aware ofall the energy paths [12].

Ground pre-ConditioningVentilation air can be pre-conditioned by pass-ing the supply air ducts under-ground. Thiscan provide a good measure of winter pre-heating and summer pre-cooling [13].

Demand Control VentilationDemand control ventilation, DCV, systems pro-vide a means by which the rate of ventilationis modulated in response to varying air qualityconditions. This is effective if a dominant pol-lutant is identifiable. In transiently occupiedbuildings, control by metabolic carbon dioxideconcentration has become popular althoughmust be introduced with caution. For success,it is essential to ensure that no other problempollutants are present [14].

Displacement VentilationDisplacement ventilation involves distributingclean air at low velocity and at a temperatureof approximately 2oK below the ambient airtemperature of the space [15]. This dense airmass moves at floor level until it reaches athermal source such as an occupant or electricequipment, causing the air to warm and gen-tly rise. Polluted air is then collected and ex-tracted above the breathing zone. This processreduces the mixing effect of classical dilutionventilation, thus reducing the amount of ven-tilation needed to achieve the same air qualityin the vicinity of occupants [15]. For success,very careful temperature control is needed andthere is a limit on potential cooling capacity[15].

III. Outdoors Air Pollution

Clean outdoor air is essential for good indoorair quality. Although air cleaning is possible, itis costly and not effective in the many officesand dwellings that are naturally ventilated,leaky or ventilated by mechanical extract sys-tems. Some air quality problems are global

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and can only be controlled by international ef-fort. Other pollutants are much more regionaland may be associated with local industry andtraffic. Nature, too, presents its own problemswith large volumes of dust and gaseous emis-sions being associated with volcanic activity.Similarly, while naturally occurring, radoncan penetrate buildings from the underlyinggeological strata. Even rural areas are notimmune to pollution, where the presence ofpollen, fungal spores and agricultural chemi-cals can result in poor health and cause allergicreactions. There are several pollution controlstrategies. Some of them are discussed below:

Filtration Filtration is applied primarily toremove particulates from the air. Filtration ofoutdoor air cannot be readily applied to themany buildings that are naturally ventilated orexcessively leaky. To be effective, filtration sys-tems must be capable of trapping the smallestof particles and of handling large volumes ofairflow. Activated carbon and other absorbingfilters are additionally able to remove gaseouspollutants [16]. Mechanical systems in residen-tial buildings contribute little to the ventilationrate. The thermal comfort is an importantaspect of human life.

Positioning of Air IntakesAir intakes must be located away from pollu-tant sources. Particular sources include streetlevel and car parking locations [16]. Althoughurban air quality is normally much improvedat elevations above street level, contaminationfrom adjacent exhaust stacks and cooling tow-ers must, also, be avoided [16]. Determiningthe optimum position for air intakes may re-quire extensive wind tunnel or fluid dynamicsanalysis. Further information on the position-ing of air intakes is reviewed by Limb 1995 [7].

Air Quality Controlled Fresh AirDampersTraffic pollution in urban areas is often highlytransient, with peaks occurring during themorning and evening commuting periods. Atthese times, it may be possible to improve

indoor air quality by temporarily closing freshair intakes and windows.

Building Air TightnessNone of the above control strategies will be ef-fective unless the building is well sealed fromthe outdoor environment to prevent contami-nant ingress through air infiltration. Under-ground parking garages must also be wellsealed from occupied accommodation above.Evidence suggests that sealing is often inade-quate [16].

IV. Indoor Pollutans

Pollutants emitted inside buildings are de-rived from metabolism (odour, carbon dioxide,and bacteria), the activities of occupants (e.g.,smoking, washing and cooking), emissionsfrom materials used in construction and fur-nishing and emissions from machinery andprocesses. The preferred order of control isdiscussed below:

Source ControlOnce a pollutant has entered a space, it can,at best, only be diluted [17]. Avoidable pol-lutants should, therefore, be eliminated. Thismeans restricting or, preferably, eliminatingpotentially harmful pollutant emissions.

Enclosing and Ventilating at SourcePollutants generated as part of the activity ofoccupants are usually highly localised. Wher-ever possible, source control should be applied,combined with the use of local extractors [17].

General VentilationGeneral ventilation of a space is needed to di-lute and remove residual pollution primarilyfrom unavoidable contaminant sources [17].

V. Ventilation of Spaces in Humid

Climate

The design of windows in modern buildingsin a warm, humid climate can be influencedeither by their use to provide physiological

8


and psychological comfort via providing airand daylight to interior spaces or by usingthem to provide aesthetically appealing fen-estration. Most spaces in modern buildingsare not adequately ventilated and it is recom-mended that effort should be directed towardsthe use of windows to achieve physiologicalcomfort. Evaluation of public housing has fo-cused on four main aspects: economics, socialand physical factors, and resident’s satisfaction.However, information about the physiologicalcharacteristics of spaces in a warm humid cli-mate will aid the design of appropriate spaceswith respect to the development and adequatechoice of building materials and appropriateuse of suitable passive energy. In this lightthere is a need to examine resident’s satisfac-tion with respect to these physiological issues.Proper ventilation in a space is a primary fac-tor in determining human health, comfort andwell being of the occupants. At present, gettinga proper naturally ventilated space seems to bea difficult task. This is partly due to the specificenvironmental problems of high temperature,high humidity, low wind velocity, and variablewind direction- usually attributed to the warmhumid climate, on the one hand, and the diffi-culty of articulating the design constraints ofsecurity, privacy and the desire of users forlarge spaces on the other hand. As pointedout by most researchers in the field of passiveenergy design, such as Givoni [18], Koenigs-berger et al., [19] Boulet [20] and Szokolay [21],the types of spaces most suited to this climateare spaces, which are cross-ventilated. This im-plies that these spaces must have openings atleast on opposite sides of a wall, but this condi-tion is difficult to achieve in view of the designconstraints mentioned above. So in most cases,the option left to the designer is to have open-ings on a wall or openings on adjacent walls.The effectiveness of the above arrangement foreffective ventilation of a space still depends onother parameters. Therefore, in order to opti-mise comfort in spaces in warm humid climate,there is a need to re-examine the factors af-fecting proper ventilation with respect to thesedesign issues. In order to be thermally com-

fortable in interior spaces, four environmentalparameters, namely air temperature, relativehumidity, mean radiant temperature and airvelocity, need to be present in the space in ad-equate proportions [21]. In a warm, humidclimate, the predominance of high humiditynecessitates a corresponding steady, continu-ous breeze of medium air speed to increase theefficiency of sweat evaporation and to avoiddiscomfort caused by moisture on skin andclothes. Continuous ventilation is therefore theprimary requirement for comfort [18]. Fromthe above, it is apparent that the most impor-tant of these comfort parameters in a warm,humid climate is air velocity. It should, also, benoted that indoor air velocity depends on thevelocity of the air outdoors [21]. The factorsaffecting indoor air movement are orientationof the building with respect to wind direction,effect of the external features of the openings,the position of openings in the wall, the sizeof the openings and control of the openings.Cross-ventilation is the most effective methodof getting appreciable air movement in interiorspaces in warm, humid climates. For comfortpurposes, the indoor wind velocity should beset at between 0.15 and 1.5 m/s [22]. A math-ematical model based on analysis of the ex-perimental results [23], which established therelationship between the average indoor andoutdoor air velocities with the windows placedperpendicular to each other, was adapted tosuit a warm, humid climate and is, usually,used to evaluate the spaces. The formula statesthat:

Where:V1 = average indoor velocityx = ratio of window area to wall areaVo = outdoor wind speed

Air Movement in BuildingsNatural ventilation is now considered to be oneof the requirements for a low energy buildingdesigns. Until about three decades ago the

9


majority of office buildings were naturally ven-tilated. With the availability of inexpensive fos-sil energy and the tendency to provide betterindoor environmental control, there has beena vast increase in the use of air-conditioningin new and refurbished buildings. However,recent scientific evidence on the impact of re-frigerants and air-conditioning systems on theenvironment has promoted the more consciousbuilding designers to give serious considera-tions to natural ventilation in non-domesticbuildings [24]. Two major difficulties that adesigner has to resolve are the questions ofairflow control and room air movement in thespace. Because of the problem of scaling andthe difficulty of representing natural ventila-tion in laboratory, most of the methods usedfor predicting the air movement in mechani-cally ventilated buildings are not very suitablefor naturally ventilated spaces [25]. However,computational fluid dynamics (CFD) is nowbecoming increasingly used for the designof both mechanical and natural ventilationsystems. Since a CFD solution is based onthe fundamental flow and energy equations,the technique is equally applicable to a natu-rally ventilated space as well as a mechanicallyventilated one, providing that a realistic repre-sentation of the boundary conditions are madein the solution.

Natural VentilationGenerally, buildings should be designed withcontrollable natural ventilation. A very highrange of natural ventilation rates is necessaryso that the heat transfer rate between insideand outside can be selected to suit conditions[25]. The ventilation rates required to con-trol summertime temperatures are very muchhigher than these required to control pollutionor odour. Any natural ventilation system thatcan control summer temperatures can readilyprovide adequate ventilation to control levelsof odour and carbon dioxide production ina building. Theoretically, it is not possibleto achieve heat transfer without momentumtransfer and loss of pressure. However, Figures2 and 3 show some ideas for achieving heat

reclaim at low velocities. Such ideas work wellfor small buildings.

Mechanical VentilationMost of the medium and large size buildingsare ventilated by mechanical systems designedto bring in outside air, filter it, supply it to theoccupants and then exhaust an approximatelyequal amount of stale air. Ideally, these systemsshould be based on criteria that can be estab-lished at the design stage. To return afterwardsin attempts to mitigate problems may lead toconsiderable expense and energy waste, andmay not be entirely successful [25]. The keyfactors that must be included in the design ofventilation systems are: code requirement andother regulations or standards (e.g., fire), venti-lation strategy and systems sizing, climate andweather variations, air distribution, diffuserlocation and local ventilation, ease of operationand maintenance and impact of system onoccupants (e.g., acoustically). These factors dif-fer for various building types and occupancypatterns. For example, in office buildings,pollutants tend to come from sources such asoccupancy, office equipment, and automobilefumes. Occupant pollutants typically includemetabolic carbon dioxide emission, odours andsometimes smoking. When occupants (and notsmoking) are the prime source. Carbon dioxideacts as a surrogate and can be used to cost-effectively modulate the ventilation, formingwhat is known as a demand controlled venti-lation system. Generally, contaminant sourcesare varied but, often, well-defined and limitingvalues are often determined by occupationalstandards.

Bioclimatic DesignBioclimatic design cannot continue to be a sideissue of a technical nature to the main archi-tectural design. In recent years started to altercourse and to become much more holistic inits approach while trying to address itself to:

• The achievement of a sustainable devel-opment.

• The depletion of non-renewable sources

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and materials.

• The life cycle analysis of buildings.

• The total polluting effects of buildings onthe environment.

• The reduction of energy consumptionand

• Human health and comfort.

Hidden dimensions of architectural cre-ation are vital to the notion of bioclimatic de-sign. The most fundamental ones are:

TIME, which has been called the fourth di-mension of architectural space, is of impor-tance because every object cannot exist but intime. The notion of time gives life to an objectand releases it to periodic (predictable) or un-periodic repetition. Times relates to seasonaland diurnal patterns and thus to climate andthe way that a building behaves or should bedesigned to couple with and not antagonise na-ture. It further releases to the dynamic nature

of a building in contrast to the static image thatwe have created for it.

AIR, is a second invisible but important el-ement. We create space and pretend that itis empty, oblivious of the fact that it is bothsurrounded by and filled with air. Air in itsturn, due to air-movement, which is generatedby either temperature or pressure differences,is very much there and alive. And related tothe movement of air should be building shapes,sections, heights, orientations and the size andpositioning of openings.

LIGHT, and in particular daylight, is a thirdimportant element. Architecture cannot ex-ist but with light and from the time we havebeen able to substitute natural light with ar-tificial lighting, many a building and a lot ofarchitecture has become poorer so. It is notan exaggeration to say that the real form giverto architecture is not the architect himself butlight and that the architect is but the formsmoulder.

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Vernacular architecture is beautiful to lookat as well as significant to contemplate on. It isparticularly interesting to realise the nature oftraditional architecture where various devicesto attain thermal comfort without resorting tofossil fuels can be seen. Sun shading and crossventilation are two major concerns in housedesign and a south-facing faÃgade is manda-tory to harness the sun in winter as much aspossible. Natural ventilation required higherceilings to bring a cooling effect to occupants inbuildings built fifty years ago, whereas modernhigh technology buildings have lower ceilingheights, thus making air conditioning manda-tory. Admitting the human right of enjoyingmodern lives with a certain level of comfortand convenience, it is necessary to consider

how people can live and work in an ideal en-vironment with the least amount of energyconsumption in the age of global environmentproblems. People in the modern age could notput up with the poor indoor environment thatpeople in the old age used to live in. In fact,in those days people had to live with the leastamount of fuels readily available and to devisevarious means of constructing their houses sothat they would be compatible with the localclimate. It is important; therefore, in designingpassive and low energy architecture for the fu-ture to learn from their spirit to overcome diffi-culties by having their creative designs adaptedto respective regional climatic conditions andto try to devise the ecotechniques in combina-tion with a high grade of modern science.

Heat gain in the summer is the main prob-lem as it overheats the indoor environment ofresidential buildings. This forces the residentsto utilise mechanical air conditioning systemsto satisfy their comfort. Under todayâAZs eco-nomic crisis, energy conversation programmesand acts for respect of environment are receiv-

ing more attention. As a contribution to suchefforts and in order to overcome the heat gainin houses, it is advisable to utilise passive sys-tems, namely, producing ventilation by a solarchimney [26]. Room air is removed by ventila-tion produced by the metallic solar wall (MSW)as shown in figure 4.

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InfiltrationInfiltration is the process of air flowing in(or out) of leaks in the building envelope,thereby providing (renewable) ventilation inan uncontrolled manner [27]. All buildings aresubject to infiltration, but it is more importantin smaller buildings as many such buildingsrely exclusively on infiltration when doors andwindows are closed. In larger buildings thereis less surface area to leak for a given amountof building volume, so the same leakage mat-ters less. More importantly, the pressures inlarger buildings are usually dominated by themechanical system and the leaks in the build-ing envelope have only a secondary impact onthe ventilation rates [27]. Infiltration in largerbuildings may, however, affect thermal com-fort and control and systems balance. Typicalminimum values of air exchange rates rangefrom 0.5 to 1.0 h-1 in office buildings [27].Buildings with higher occupant density willhave higher minimum outside air exchangerates when ventilation is based on outdoorair supply per occupant, typically 7 to 10 ls-1[27]. Thus, schools have minimum outdoor airventilation rates 3 h-1, while fully occupiedtheatres, auditoriums and meeting rooms mayhave minimum air exchange rates of 4 to 7 h-1[27]. It is in low-rise residential buildings (mosttypically, single-family houses) that infiltrationis a dominant force. Mechanical systems in

these buildings contribute little to the ventila-tion rate.

Passive Ventilation SystemsPassive solar systems for space heating andcooling, as well as passive cooling techniquescan significantly contribute to energy saving inthe building sector when used in combinationwith conventional systems for heating, cooling,ventilation and lighting. The overall thermalbehaviour of the building is dependent onthe alternatives and interventions made onthe building’s shell. Passive ventilation sys-tems share the use of renewable energy toprovide ventilation with infiltration. But un-like air leakage and open windows, passiveventilation systems are designed to providespecific amounts of ventilation to minimiseboth energy liabilities due to excessive venti-lation and periods of poor air quality due tounder-ventilation [28]. However, the most com-mon passive ventilation system is the passivestack, which is normally used to extract airfrom kitchen and bathrooms. In this method,prevailing wind and temperature differencesare used to drive airflow through a verticalshaft. Various stack designs can be used tocontrol or enhance the performance, based onlocal climate. However, careful design is re-quired to avoid backdraughting and to insureproper mean rates. Although there is signifi-

13


cant experience with this approach in Europe,it has been rarely used in North America [28].Well-designed passive ventilation systems canbe used to provide whole-building ventilationas well as local exhaust. Some efforts are cur-rently underway to develop passive ventilationsystems that incorporate heat recovery to min-imise the need for conditioning the ventilationair [28]. These approaches aim towards a fullyrenewable ventilation system in that it requiresno non-renewable resources for either provid-ing the ventilation air or conditioning it. Atraditional, naturally ventilated building canreadily provide a high ventilation rate. On theother hand, the mechanical ventilation systemsare very expensive. However, a comprehensiveecological concept can be developed to achievea reduction of electrical and heating energyconsumption and optimise natural air condi-tion and ventilation.

Passive CoolingIn the office environment, high heat loads arecommonly developed through lighting, com-puters and other electrical equipment. Fur-ther heat gains are developed through solargains, occupants and high outdoor air temper-ature. Passive cooling methods attempt to re-duce or eliminate the need for energy intensiverefrigerative cooling by minimising heat gains.This involves taking advantage of thermal mass(night cooling) and introducing high levels ofair change. Night ventilation techniques seemto be the most appropriate strategy for build-ings. This arises as a consequence of the largediurnal temperature range during the coolingseasons and the relatively low peak air temper-atures, which occur during the day [29]. Sucha combination allows the thermal mass of thebuilding to use the cool night air to discardthe heat absorbed during the day. An initialexamination of the weather conditions experi-enced during the summer months of June toSeptember in the UK indicates that most peakconditions of external weather fall within theventilation and thermal mass edge of the bio-climatic chart [29, 30]. Figure 5 shows that thesummer (June to September) climatic envelope

is within the heating, comfort, thermal massand ventilation effectiveness areas of the chart.The key parameters influencing the effective-ness of night cooling are summarised into thefollowing four categories [30]:

• Internal heat gains of 10, 25 and 40W/m2; representing occupancy only, oc-cupancy plus lights, and occupancy to-gether with lights and IT load respec-tively.

• Envelope gains.

• Thermal response.

• Ventilation gains/losses.

Due to the complexity resulting from allthe interrelated parameters affecting the effec-tiveness of night ventilation, it is necessaryfor designers to have access to a simple userfriendly and yet accurate model when assess-ing the viability of night ventilation during theinitial design stage. The followings are the keyoutput parameters [30]:

• Maximum dry resultant temperature dur-ing the occupied period.

• Dry resultant temperature at the start ofthe occupied period.

• Energy savings.

Maximising the efficiency and benefitgained from a greenhouse can be achieved us-ing various approaches, employing differenttechniques that could be applied at the design,construction or operational stages. Greenhousecultivation is one of the most absorbing and re-warding form of gardening for anyone who en-joys growing plants. The enthusiastic gardenercan adapt the greenhouse climate to suit a par-ticular group of plants, or raise flowers, fruitand vegetables out of their natural season. Thecomfort in greenhouse depends on many envi-ronmental parameters. These include tempera-ture, relative humidity, air quality and lighting.Although greenhouse and conservatory origi-nally both meant a place to house or conserve

14


greens (variegated hollies, cirrus, myrtles andoleanders), a greenhouse today implies a placein which plants are raised while conservatoryusually describes a glazed room where plants

may or may not play a significant role. Indeed,a greenhouse can be used for so many differentpurposes.

The input data required are the following:

• Thermal gains related data: solar pro-tection is assumed good, thermal gainscan be varied and the user specifies theoccupancy period.

• Building fabric data: glazing ratio canbe any value while thermal mass can bevaried at three levels.

• Ventilation data: infiltration, day ventila-tion and night ventilation can be specifiedas necessary.

• Weather data: solar data are fixed buttemperature is user specified for sevendays although temperature profiles neednot be the same for all days. The weatherdata are specified in the form of maxi-mum and minimum temperature for eachday and hourly values are calculated bysinusoidal fitting.

However, a primary strategy for coolingbuildings without mechanical intervention in

hot humid climates is to promote natural ven-tilation. To control the energy used for thecooling of buildings in hot-arid regions withambient air temperatures during the hottestperiod between 42 to 47 ◦C, passive cooling ap-proaches should be implemented [30]. A solarchimney that employs convective currents todraw air out of the building could be used.By creating a hot zone with an exterior outlet,air can be drawn into the house, ventilatingthe structure as well as the occupants. Sincesolar energy in such a region is immense, thehot zone created with a black metal sheet onthe glazing element can draw hotter air at aslightly higher speed [30]. Applications of so-lar chimneys in buildings were limited to ex-ternal walls. Integrating a solar chimney withan evaporatively cooled cavity could result ina better cooling effect. However, this shouldbe applied with care since water sources arelimited [31]. Figure 6 shows the combinedwall-roof solar chimney incorporated into thatbuilding. Average room and ambient air tem-peratures are 23 and 27 ◦C respectively. Air

15


velocity required to achieve thermal comfortin the room should reach a maximum of 0.3m/s [31]. Figure 7 gives the cooling load ver-sus air change per hour. This indicates thatthe inclined airflow by the combined wall-roofchimney is enough to overcome a high coolingload required to cool heavy residential build-ings. This suggests that night ventilation couldbe improved, and incorporating a combinedwall-roof solar chimney increases the cooling

load. However, thermal mass and ventilationshould be sufficient to cover cooling require-ments in typical buildings. A high percent-age of the cooling requirements can be met bynight ventilation before another form of cool-ing is used. Finally, a simplified ventilation toolfor assessing the applicability of night coolingin buildings, currently under development interms of user inputs and typical outputs.

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VI. Air Pollutans and

Transmutation

Controlling the pollution of the present civili-sation in an increasing concern. More impor-tance is given to control global carbon dioxide,which is considered to be the main factor ofgreen house effect. Though the complete exper-imental result on the fact is yet to be debated,the immense heat, temperature and turbulenceof nuclear explosion oxidising the atmosphericnitrogen into nitric oxide, are considered tobe similarly responsible for depletion of ozonelayer [32]. At present, more importance is givenfor plantation to reduce the level of global car-bon dioxide. The plantation over the wholeearth surface may control only 50% of carbondioxide disposed to atmosphere and its green-house effect. There are, also, explosions in theozone layer time to time to add to the problem.Irrespective of the relative importance of eachfactor, the ozone layer protects us from harm-ful cosmic radiations and it is believed that thedepletion of ozone layer increases the threat ofouter radiations to human habitation if envi-ronmental pollution is not controlled or thereis no possibility of self-sustainable stability innature [32].

The presence of ionosphere in the outer-sphere is most probably for ionic dissociationof the gases of the outer-sphere in the pres-ence of low pressure and cosmic radiation [32].Moreover the ionosphere contains charged he-lium ions (alpha particle). Therefore, it may beconcluded that the explosion in the ozone andtransmission of radiations through it are thepossible effects of transmutation of pollutantswith exothermic reaction (emission of radia-tions) [32]. The existence of a black hole inthe space, which is found in the photo cameraof astrologist, is still unexplored. This blackhole may be an effect of transmutation processwith absorption of heat energy (endothermicreaction). The idea of transmutation of pollu-tants has been proposed for one or more of thefollowing reasons:

• The experimental results support thetransmutation of materials.

• To search the sinks of the remaining car-bon dioxide not absorbed by plants orseawater.

• To find out the possible causes of explo-sion in the ozone layer other than thedepletion of ozone layer.

• To investigate the possibilities of the self-sustaining stability of global environ-ment.

To prove the portable of transmutation ofpollutants, experimental investigations may beconducted to bombard C or CO2 or CH4 orother air pollutants by accelerated alpha parti-cles in a low-pressure vacuum tube in a similarcondition of ionosphere. Heating them withgamma radiation can accelerate the alpha par-ticles. The results of such experimental investi-gation may prove the probable transmutationof pollutants and self-sustaining equilibriumof the global environment.

VII. Greenhouses

Population growth and less availability offood material have become global concerns.The world population increases exponentiallywhereas food production has increased onlyarithmetically, meaning that the availability offood per capita has decreased. This is more pro-nounced in the cases of oils, vegetables, fruitsand milk, whereas it is marginal, rather thanminimum, in cereals. The increase in popula-tion has also resulted in the use of more urbanareas for habitation, less land available for cul-tivation and, hence, more food requirements.The resultant need is, therefore, to increase pro-ductivity and year round cultivation. To max-imise production and meet the global demandon food, vegetables, flowers and horticulturalcrops, it is necessary to increase the effectiveproduction span of crops.

The sun is the source of energy for plantsand animals. This energy is converted intofood (i.e., carbohydrates) by plants through aprocess called photosynthesis. This process isaccomplished at suitable atmospheric condi-tions. These conditions are provided by nature

17


in different seasons and artificially by a green-house. The primary objective of greenhousesis to produce agricultural products outside thecultivation season. They offer a suitable micro-climate for plants and make possible growthand fruiting, where it is not possible in openfields. This is why a greenhouse is also knownas a ’controlled environment greenhouse’.

Through a controlled environment, green-house production is advanced and can be con-tinued for longer duration, and finally, produc-tion is increased [33]. The off-season produc-tion of flowers and vegetables is the uniquefeature of the controlled environment green-house.

Hence, greenhouse technology has evolvedto create the favourable environment, or main-taining the climate, in order to cultivate the de-sirable crop the year round. The use of ’main-taining the climate’ concept may be extendedfor crop drying, distillation, biogas plant heat-ing and space conditioning.

The use of greenhouses is widespread. Dur-ing the last 10 years, the amount of green-houses has increased considerably to cover upto several hundred hectares at present. Mostof the production is commercialised locally orexported. In India, about 300 ha of land areunder greenhouse cultivation.

On the higher side, however, it is 98600 hain Netherlands, 48000 ha in China and 40000ha in Japan [34]. This shows that there is alarge scope to extend greenhouse technologyfor various climates.

However, the effective utilisation of green-houses has to deal with some specific climateproblems like frost, during winter and over-heating in summer days. These problems showthe necessity of having a tool capable of pre-dicting the thermal behaviour of a greenhouseunder specific exterior conditions. Also, green-house industry has to deal with some problemsrelated to a poor design of a great number ofgreenhouses. Such problems are mostly relatedto, on the one hand, its incapacity to deal withthe problem of frost, which in the cold clear skydays of winter can destroy the whole work ofa season, and, on the other hand, the question

of overheating in the summer days.

VIII. Effects of Urban Density

Compact development patterns can reduce in-frastructure demands and the need to travelby car. As population density increases, trans-portation options multiply and dependenceareas, per capita fuel consumption is muchlower in densely populated areas because peo-ple drive so much less. Few roads and com-mercially viable public transport are the majormerits. On the other hand, urban density isa major factor that determines the urban ven-tilation conditions, as well as the urban tem-perature. Under given circumstances, an ur-ban area with a high density of buildings canexperience poor ventilation and strong heatisland effect. In warm-humid regions thesefeatures would lead to a high level of thermalstress of the inhabitants and increased use ofenergy in air-conditioned buildings. With in-creasing urbanisation in the world, cities aregrowing in number, population and complex-ity. At present, 2% of the world’s land surfaceis covered by cities, yet the people living inthem consume 75% of the resources consumedby mankind. The reality of modern urbanisa-tion inevitably leads to higher densities than intraditional settlements and this trend is partic-ularly notable in developing countries. Today,the challenge before many cities to supportlarge numbers of people while limiting theirimpact on the natural environment.

However, it is also possible that a high-density urban area, obtained by a mixture ofhigh and low buildings, could have better ven-tilation conditions than an area with lowerdensity but with buildings of the same height.Closely spaced or high-rise buildings are alsoaffected by the use of natural lighting, naturalventilation and solar energy. If not properlyplanned, energy for electric lighting and me-chanical cooling/ventilation may be increasedand application of solar energy systems will begreatly limited. Table 1 gives a summary of thepositive and negative effects of urban density.

All in all, denser city models require more

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careful design in order to maximise energyefficiency and satisfy other social and develop-ment requirements. Low energy design shouldnot be considered in isolation, and in fact, itis a measure, which should work in harmonywith other environmental objectives. Hence,

building energy study provides opportunitiesnot only for identifying energy and cost sav-ings, but also for examining the indoor andoutdoor environment.

Architectural ExpressionThe focus of the world’s attention on environ-mental issues in recent years has stimulatedresponse in many countries, which have ledto a closer examination of energy conservationstrategies for conventional fossil fuels. Build-ings are important consumers of energy andthus important contributors to emissions ofgreenhouse gases into the global atmosphere.The development and adoption of suitable re-newable energy technology in buildings has animportant role to play. A review of options in-dicates benefits and some problems [27]. Thereare two key elements to the fulfilling of renew-able energy technology potential within the

field of building design; first the installationof appropriate skills and attitudes in buildingdesign professionals and second the provisionof the opportunity for such people to demon-strate their skills. This second element mayonly be created when the population at largeand clients commissioning building design inparticular, become more aware of what canbe achieved and what resources are required.Terms like passive cooling or passive solar usemean that the cooling of a building or the ex-ploitation of the energy of the sun is achievednot by machines but by the building’s partic-ular morphological organisation. Hence, thepassive approach to themes of energy savings

19


is essentially based on the morphological ar-ticulations of the constructions. Passive solardesign, in particular, can realise significant en-ergy and cost savings. For a design to be suc-cessful, it is crucial for the designer to havea good understanding of the use of the build-ing. Few of the buildings had performed asexpected by their designers. To be more precise,their performance had been compromised bya variety of influences related to their design,construction and operation. However, thereis no doubt that the passive energy approachis certainly the one that, being supported bythe material shape of the buildings has a di-rect influence on architectural language andmost greatly influences architectural expres-siveness [30]. Furthermore, form is a main toolin architectural expression. To give form tothe material things that one produces is an in-eluctable necessity. In architecture, form, infact, summarises and gives concreteness to itsevery value in terms of economy, aesthetics,functionality and, consequently, energy effi-ciency [31]. The target is to enrich the expres-sive message with forms producing an advan-tage energy-wise. Hence, form, in its geometricand material sense, conditions the energy effi-ciency of a building in its interaction with theenvironment. It is, then, very hard to extractand separate the parameters and the elementsrelative to this efficiency from the expressiveunit to which they belong. By analysing energyissues and strategies by means of the designs,of which they are an integral part, one will,more easily, focus the attention on the rela-tionship between these themes, their specificcontext and their architectural expressiveness.Many concrete examples and a whole literaturehave recently grown up around these subjectsand the wisdom of forms and expedients thatbelong to millennia-old traditions has been re-discovered. Such a revisiting, however, is only,or most especially, conceptual, since it must befiltered through today’s technology and needs;both being almost irreconcilable with those ofthe past. Two among the historical conceptsare of special importance. One is rooted in theeffort to establish rational and friendly strate-

gic relations with the physical environment,while the other recognises the interactions be-tween the psyche and physical perceptions inthe creation of the feeling of comfort. The for-mer, which may be defined as an alliance withthe environment deals with the physical pa-rameters involving a mixture of natural andartificial ingredients such as soil and vegeta-tion, urban fabrics and pollution [32]. The mostdominant outside parameter is, of course, thesun’s irradiation, our planet’s primary energysource. All these elements can be measured inphysical terms and are therefore the subject ofscience. Within the second concept, however,one considers the emotional and intellectualenergies, which are the prime inexhaustiblesource of renewable power [33]. In this case,cultural parameters, which are not exactly mea-surable, are involved. However, they representthe very essence of the architectural quality.Objective scientific measurement parameterstell us very little about the emotional way ofperceiving, which influences the messages ofhuman are physical sensorial organs. The per-ceptual reality arises from a multitude of sen-sorial components; visual, thermal, acoustic,olfactory and kinaesthetics. It can, also, arisefrom the organisational quality of the spacein which different parameters come together,like the sense of order or of serenity. Likewise,practical evaluations, such as usefulness, canbe involved too. The evaluation is a whollysubjective matter, but can be shared by a set ofexperiencing persons [31]. Therefore, these cul-tural parameters could be different in differentcontexts in spite of the inexorable levelling ona planet- wide scale. However, the parameterschange in the anthropological sense, not onlywith the cultural environment, but also in rela-tion to function. The scientifically measurableparameters can, thus, have their meanings veryprofoundly altered by the non-measurable, butdescribable, cultural parameters.

However, the low energy target also meansto eliminate any excess in the quantities ofmaterial and in the manufacturing process nec-essary for the construction of our built envi-ronment. This claims for a more sober, elegant

20


and essential expression, which is not jeopar-dising at all, but instead enhancing, the rich-ness and preciousness of architecture, whilecontributing to a better environment from anaesthetic viewpoint [34]. Arguably, the mostsuccessful designs were in fact the simplest.Paying attention to orientation, plan and formcan have far greater impact on energy perfor-mance than opting for elaborate solutions [34].However, a design strategy can fail when thoseresponsible for specifying materials for exam-ple, do not implement the passive solar strat-egy correctly. Similarly, cost-cutting exercisescan seriously upset the effectiveness of a de-sign strategy. Therefore, it is imperative thata designer fully informs key personnel, suchas the quantity surveyor and client, about theirdesign and be prepared to defend it. Therefore,the designer should have an adequate under-standing of how the occupants or processes,such as ventilation, would function within thebuilding. Thinking through such processes inisolation without reference to others can leadto conflicting strategies, which can have a detri-mental impact upon performance. Likewise,if the design intent of the building is not com-municated to its occupants, there is a risk thatthey will use it inappropriately, thus, compro-mising its performance. Hence, the designershould communicate in simple terms the ac-tions expected of the occupant to control thebuilding. For example, occupants should bewell informed about how to guard against sum-mer overheating. If the designer opted for asimple, seasonally adjusted control; say, insu-lated sliding doors were to be used betweenthe mass wall and the internal space.

The lesson here is that designers must beprepared to defend their design such thatothers appreciate the importance and interre-lationship of each component. A strategy willonly work if each individual component is con-sidered as part of the bigger picture. Failureto implement a component or incorrect instal-lation, for example, can lead to failure of thestrategy and consequently, in some instances,the building may not liked by its occupantsdue to its poor performance.

Sustainable PracticesWithin the last decade sustainable developmentand building practices have acquired great im-portance due to the negative impact of vari-ous development projects on the environment.In line with a sustainable development ap-proach, it is critical for practitioners to create ahealthy, sustainable built environment [31, 32and 33]. In Europe, 50% of material resourcestaken from nature are building-related, over50% of national waste production comes fromthe building sector and 40% of energy con-sumption is building-related [30]. Therefore,more attention should be directed towards es-tablishing sustainable guidelines for practition-ers. Furthermore, the rapid growth in popu-lation has led to active construction that, insome instances, neglected the impact on the en-vironment and human activities. At the sametime, the impact on the traditional heritage, anoften-neglected issue of sustainability, has notbeen taken into consideration, despite repre-senting a rich resource for sustainable buildingpractices.

Sustainability has been defined as theextent to which progress and developmentshould meet the need of the present withoutcompromising the ability of the future genera-tions to meet their own needs [30]. This encom-passes a variety of levels and scales rangingfrom economic development and agriculture,to the management of human settlements andbuilding practices. This general definition wasfurther developed to include sustainable build-ing practices and management of human set-tlements. The following issues were addressedduring the Rio Earth Summit in 1992 [30]:

• The use of local materials and indigenousbuilding sources.

• Incentive to promote the continuation oftraditional techniques, with regional re-sources and self-help strategies.

• Regulation of energy-efficient designprinciples.

• International information exchange on

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all aspects of construction related to theenvironment, among architects and con-tractors, particularly non-conventional re-sources.

• Exploration of methods to encourage andfacilitate the recycling and reuse of build-ing materials, especially those requiringintensive energy use during manufactur-ing, and the use of clean technologies.

The objectives of the sustainable buildingpractices aim to:

• Develop a comprehensive definition ofsustainability that includes socio-cultural,bio-climate, and technological aspects.

• Establish guidelines for future sustain-able architecture.

• Predict the CO2 emissions in buildings.

• The proper architectural measure for sus-tainability is efficient, energy use, wastecontrol, population growth, carrying ca-pacity, and resource efficiency.

• Establish methods of design that con-serve energy and natural resources.

A building inevitably consumes materialsand energy resources. The technology is avail-able to use methods and materials that reducethe environmental impacts, increase operatingefficiency, and increase durability of buildings(Table 2). Literature on green buildings revealsa number of principles that can be synthesisedin the creation of the built environment that issustainable. According to Lobo [14], these are:land development, building design and con-struction, occupant considerations, life cycle as-sessment, volunteer incentives and marketingprogrammes, facilitate reuse and remodelling,and final disposition of the structure. Theseparameters and many more are essential foranalysis, making them an important element

of the design decision-making process. Today,architects should prepare for this as well asdealing with existing buildings with many un-favourable urban environmental factors, suchas many spaces have no choice of orientation,and, often, set in noisy streets with their win-dows opening into dusty and polluted air andsurrounding buildings overshadowing them.

Buildings and CO2 EmissionTo achieve carbon dioxide, CO2, emission tar-gets, more fundamental changes to buildingdesigns have been suggested [35]. The ac-tual performance of buildings must also beimproved to meet the emission targets. Tothis end, it has been suggested that the per-formance assessment should be introduced toensure that the quality of construction, instal-lation and commissioning achieve the designintent. Air-tightness and the commissioning ofplant and controls are the main two elementsof assessing CO2 emission. Air-tightness isimportant as uncontrolled air leakage wastesenergy. Uncertainties over infiltration rates areoften the reason for excessive design marginsthat result in oversized and inefficient plants.On the other hand, commissioning to acceptprocedures would significantly improve energyefficiency. The slow turnover in the buildingstock means that improved performance ofnew buildings will only cut CO2 emissionssignificantly in the long term. Consequently,the performance of existing buildings mustbe improved. For example, improving 3% ofexisting buildings would be more effectivein cutting emissions than, say, improving thefabric standards for new non-domestic build-ings and improving the efficiency of new airconditioning and ventilation systems [27]. Areduction in emissions arising from urban ac-tivities can, however, only be achieved by acombination of energy efficiency measures anda move away from fossil fuels.

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Energy Efficiency most Cost-effectiveEnergy efficiency is the most cost-effective wayof cutting carbon dioxide emissions and im-provements to households and businesses. Itcan also have many other additional social, eco-nomic and health benefits, such as warmerand healthier homes, lower fuel bills and com-pany running costs and, indirectly, jobs. Britainwastes 20 per cent of its fossil fuel and electric-ity use. This implies that it would be cost-effective to cut Âc 10 billion a year off the col-lective fuel bill and reduce CO2 emissions bysome 120 million tones. Yet, due to lack ofgood information and advice on energy sav-ing, along with the capital to finance energyefficiency improvements, this huge potentialfor reducing energy demand is not being re-

alised. Traditionally, energy utilities have beenessentially fuel providers and the industry haspursued profits from increased volume of sales.Institutional and market arrangements havefavoured energy consumption rather than con-servation. However, energy is at the centre ofthe sustainable development paradigm as fewactivities affect the environment as much asthe continually increasing use of energy. Mostof the used energy depends on finite resources,such as coal, oil, gas and uranium. In addi-tion, more than three quarters of the world’sconsumption of these fuels is used, often in-efficiently, by only one quarter of the world’spopulation. Without even addressing these in-equities or the precious, finite nature of theseresources, the scale of environmental damage

23


will force the reduction of the usage of thesefuels long before they run out. Throughout theenergy generation process there are impacts onthe environment on local, national and inter-national levels, from opencast mining and oilexploration to emissions of the potent green-house gas carbon dioxide in ever increasingconcentration. Recently, the world’s leading cli-mate scientists reached an agreement that hu-man activities, such as burning fossil fuels forenergy and transport, are causing the world’stemperature to rise. The IntergovernmentalPanel on Climate Change has concluded that’the balance of evidence suggests a discerniblehuman influence on global climate’. It pre-dicts a rate of warming greater than any oneseen in the last 10,000 years, in other words,throughout human history. The exact impactof climate change is difficult to predict and willvary regionally. It could, however, include sealevel rise, disrupted agriculture and food sup-plies and the possibility of more freak weatherevents such as hurricanes and droughts. In-deed, people already are waking up to thefinancial and social, as well as the environ-mental, risks of unsustainable energy genera-tion methods that represent the costs of the im-pacts of climate change, acid rain and oil spills.The insurance industry, for example, concernedabout the billion dollar costs of hurricanes andfloods, has joined sides with environmentaliststo lobby for greenhouse gas emissions reduc-tion. Friends of the earth are campaigning for amore sustainable energy policy, guided by theprinciple of environmental protection and withthe objectives of sound natural resource man-agement and long-term energy security. Thekey priorities of such an energy policy must beto reduce fossil fuel use, move away from nu-clear power, improve the efficiency with whichenergy is used and increase the amount of en-ergy obtainable from sustainable, renewablesources. Efficient energy use has never beenmore crucial than it is today, particularly withthe prospect of the imminent introduction ofthe climate change levy (CCL). Establishing anenergy use action plan is the essential foun-dation to the elimination of energy waste. A

logical starting point is to carry out an energyaudit that enables the assessment of the energyuse and determine what actions to take. Theactions are best categorised by splitting mea-sures into the following three general groups:(1) High priority/low cost:

These are normally measures, which re-quire minimal investment and can be imple-mented quickly. The followings are some ex-amples of such measures:

• Good housekeeping, monitoring energyuse and targeting waste-fuel practices.

• Adjusting controls to match require-ments.

• Improved greenhouse space utilisation.

• Small capital item time switches, ther-mostats, etc.

• Carrying out minor maintenance and re-pairs.

• Staff education and training.

• Ensuring that energy is being purchasedthrough the most suitable tariff or con-tract arrangements.

(2) Medium priority/medium cost:Measures, which, although involve little or

no design, involve greater expenditure and cantake longer to implement. Examples of suchmeasures are listed below:

• New or replacement controls.

• Greenhouse component alteration e.g., in-sulation, sealing glass joints, etc.

• Alternative equipment components e.g.,energy efficient lamps in light fittings,etc.

(3) Long term/high cost:These measures require detailed study and

design. They can be best represented by thefollowings:

• Replacing or upgrading of plant andequipment.

• Fundamental redesign of systems e.g.,CHP installations.

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This process can often be a complex ex-perience and therefore the most cost-effectiveapproach is to employ an energy specialist tohelp.

Energy efficiency brings health, productiv-ity, safety, comfort and savings to homeowners,as well as local and global environmental ben-efits. The use of renewable energy resourcescould play an important role in this context,especially with regard to responsible and sus-tainable development.

Policy Recommendations for a Sustain-able Energy FutureSustainability is regarded as a major considera-tion for both urban and rural development.People have been exploiting the natural re-sources with no consideration to the effects,both short-term (environmental) and long-term(resources crunch). It is also felt that knowl-edge and technology have not been used ef-fectively in utilising energy resources. Energyis the vital input for economic and social de-velopment of any country. Its sustainabilityis an important factor to be considered. Theurban areas depend, to a large extent, on com-mercial energy sources. The rural areas usenon-commercial sources like firewood and agri-cultural wastes. With the present day trends forimproving the quality of life and sustenance ofmankind, environmental issues are consideredhighly important. In this context, the term en-ergy loss has no significant technical meaning.Instead, the exergy loss has to be considered,as destruction of exergy is possible. Hence,exergy loss minimisation will help in sustain-ability. In the process of developing, there aretwo options to manage energy resources: (1)End use matching/demand side management,which focuses on the utilities. The mode ofobtaining this is decided based on economicterms. It is, therefore, a quantitative approach.(2) Supply side management, which focuses onthe renewable energy resource and methodsof utilising it. This is decided based on ther-modynamic consideration having the resource-user temperature or exergy destruction as theobjective criteria. It is, therefore, a qualita-

tive approach. The two options are explainedschematically in Figure 8. The exergy-basedenergy, developed with supply side perspec-tive is shown in Figure 9. The following policymeasures had been identified:

• Clear environmental and social objectivesfor energy market liberalisation, includ-ing a commitment to energy efficiencyand renewables.

• Economic, institutional and regulatoryframeworks, which encourage the tran-sition to total energy services, and eco-nomic measures to encourage utility in-vestment in energy efficiency (e.g., levieson fuel bills).

• Incentives for demand side management,including grants for low-income house-holds, expert advice and training, stan-dards for appliances and buildings andtax incentives.

• Research and development funding forrenewable energy technologies not yetcommercially viable.

• Continued institutional support for newrenewables (such as standard cost-reflective payments and obligation onutilities to buy).

• Ecological tax reform to internalise exter-nal environmental and social costs withinenergy prices.

• Planning for sensitive development andpublic acceptability for renewable energy.

Energy resources are needed for societaldevelopment. Their sustainable developmentrequires a supply of energy resources that aresustainably available at a reasonable cost andcan cause no negative societal impacts. Energyresources such as fossil fuels are finite and lacksustainability, while renewable energy sourcesare sustainable over a relatively longer term.Environmental concerns are also a major factorin sustainable development, as activities, whichdegrade the environment, are not sustainable.

25


Hence, as much as environmental impact is as-sociated with energy, sustainable developmentrequires the use of energy resources, whichcause as little environmental impact as possi-ble. One way to reduce the resource depletionassociated with cycling is to reduce the losses

that accompany the transfer of exergy to con-sume resources by increasing the efficiency ofexergy transfer between resources i.e., increas-ing the fraction of exergy removed from oneresource that is transferred to another [9].

As explained above, exergy efficiency maybe thought of as a more accurate measure of en-ergy efficiency that accounts for quantity andquality aspects of energy flows. Improved ex-ergy efficiency leads to reduced exergy losses.Most efficiency improvements produce direct

environmental benefits in two ways. First, op-erating energy input requirements are reducedper unit output, and pollutants generated arecorrespondingly reduced. Second, considera-tion of the entire life cycle for energy resourcesand technologies suggests that improved effi-

26


ciency reduces environmental impact duringmost stages of the life cycle. Quite often, themain concept of sustainability, which often in-spires local and national authorities to incorpo-rate environmental consideration into settingup energy programmes have different mean-ings in different contexts though it usually em-bodies a long-term perspective. Future energysystems will largely be shaped by broad andpowerful trends that have their roots in ba-

sic human needs. Combined with increasingworld population, the need will become moreapparent for successful implementation of sus-tainable development.

Heat has a lower exergy, or quality of en-ergy, compared with work. Therefore, heat can-not be converted into work by 100% efficiency.Some examples of the difference between en-ergy and exergy are shown in Table 3.

The terms used in Table 3 have the follow-ing meanings:

Where To is the environment temperature(K) and Ts is the temperature of the stream (K).

Various parameters are essential to achiev-ing sustainable development in a society. Someof them are as follows:

• Public awareness

• Information

• Environmental education and training

• Innovative energy strategies

• Renewable energy sources and cleanertechnologies

• Financing

• Monitoring and evaluation tools.

Implementation of greenhouses offers achance for maintenance and repair services. It

is expected that the pace of implementationwill increase and the quality of work improvein addition to building the capacity of the pri-vate and district staff in contracting procedures.The financial accountability is important andshould be made transparent. The developmentof a renewable energy in a country dependson many factors. Those important to successare listed below:

(1) Motivation of the population The popu-lation should be motivated towards awarenessof high environmental issues, rational use ofenergy in order to reduce cost. Subsidy pro-gramme should be implemented as incentivesto install renewable energy plants. In addition,image campaigns to raise awareness of renew-able technology.

(2) Technical product development Toachieve technical development of renewableenergy technologies the following should beaddressed:

• Increasing the longevity and reliability ofrenewable technology

• Adapting renewable technology to house-hold technology (hot water supply)

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• Integration of renewable technology inheating technology

• Integration of renewable technology inarchitecture, e.g., in the roof or faÃgadeDevelopment of new applications, e.g.,solar cooling

• Cost reduction.

(3) Distribution and sales Commercialisationof renewable energy technology requires:

• Inclusion of renewable technology in theproduct range of heating trades at all lev-els of the distribution process (wholesale,retail)

• Building distribution nets for renewabletechnology

• Training of personnel in distribution andsales

• Training of field sales force

(4) Consumer consultation and installation Toencourage all sectors of the population to par-ticipate in adoption of renewable energy tech-nologies, the following has to be realised:

• Acceptance by craftspeople, marketingby them

• Technical training of craftspeople, initialand follow-up training programmes

• Sales training for craftspeople

• Information material to be made avail-able to craftspeople for consumer consul-tation

(5) Projecting and planning Successful applica-tion of renewable technologies also requires:

• Acceptance by decision makers in thebuilding sector (architects, house tech-nology planners, etc.)

• Integration of renewable technology intraining

• Demonstration projects/architecturecompetitions

• Renewable energy project developersshould prepare to participate in the car-bon market by:

1. Ensuring that renewable energy projectscomply with Kyoto Protocol require-ments.

2. Quantifying the expected avoided emis-sions.

3. Registering the project with the requiredoffices.

4. Contractually allocating the right to thisrevenue stream.

Other ecological measures employed on thedevelopment include:

1. Simplified building details

2. Reduced number of materials

3. Materials that can be recycled or reused

4. Materials easily maintained and repaired

5. Materials that do not have a bad influenceon the indoor climate (i.e., non-toxic)

6. Local cleaning of grey water

7. Collecting and use of rainwater for out-door purposes and park elements

8. Building volumes designed to give maxi-mum access to neighbouring park areas

9. All apartments have visual access to bothbackyard and park

(6) Energy saving measures The following en-ergy saving measures should also be consid-ered:

1. Building integrated solar PV system

2. Day-lighting

3. Ecological insulation materials

4. Natural/hybrid ventilation

5. Passive cooling

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6. Passive solar heating

7. Solar heating of domestic hot water

8. Utilisation of rainwater for flushing

Improving access for rural and urban low-income areas in developing countries throughenergy efficiency and renewable energies. Sus-tainable energy is a prerequisite for develop-ment. Energy-based living standards in de-veloping countries, however, are clearly belowstandards in developed countries. Low levelsof access to affordable and environmentallysound energy in both rural and urban low-income areas are therefore a predominant issuein developing countries. In recent years manyprogrammes for development aid or technicalassistance have been focusing on improving ac-cess to sustainable energy, many of them withimpressive results.

Apart from success stories, however, ex-perience also shows that positive appraisalsof many projects evaporate after completionand vanishing of the implementation expertteam. Altogether, the diffusion of sustainabletechnologies such as energy efficiency and re-newable energies for cooking, heating, lighting,electrical appliances and building insulation indeveloping countries has been slow.

Energy efficiency and renewable energyprogrammes could be more sustainable andpilot studies more effective and pulse releas-ing if the entire policy and implementationprocess was considered and redesigned fromthe outset. New financing and implementa-tion processes are needed which allow reallo-cating financial resources and thus enablingcountries themselves to achieve a sustainableenergy infrastructure. The links between theenergy policy framework, financing and im-plementation of renewable energy and energyefficiency projects have to be strengthened, andcapacity building efforts are required [36-38].

IX. Greenhouse Environment

The comfort in a greenhouse depends on manyenvironmental parameters. These include tem-perature, relative humidity, air quality and

lighting. Although greenhouse and conserva-tory originally both meant a place to house orconserve greens (variegated hollies, cirrus, myr-tles and oleanders), a greenhouse today impliesa place in which plants are raised while conser-vatory usually describes a glazed room whereplants may or may not play a significant role.Indeed, a greenhouse can be used for so manydifferent purposes. It is, therefore, difficult todecide how to group the information about theplants that can be grown inside it. Whereasheat loss in winter a problem, it can be a posi-tive advantage when greenhouse temperaturessoar considerably above outside temperaturesin summer. Indoor relative humidity control isone of the most effective long-term mite con-trol measures. There are many ways in whichthe internal relative humidity can be controlledincluding the use of appropriate ventilation,the reduction of internal moisture productionand maintenance of adequate internal temper-atures through the use of efficient heating andinsulation.

The introduction of a reflecting wall at theback of a greenhouse considerably enhancesthe solar radiation that reaches the ground levelat any particular time of the day. The energyyield of the greenhouse with any type of reflect-ing wall was also significantly increased. Theincrease in energy efficiency was obtained bycalculating the ratio between the total energyreceived during the day in greenhouse with areflecting wall, compared to that in a classicalgreenhouse. Hence, the energy balance wassignificantly shifted towards conservation ofclassical energy for heating or lighting. Thefour-fold greater amount of energy that canbe captured by virtue of using a reflectingwall with an adjustable inclination and louversduring winter attracts special attention. Whensky (diffuse) radiation that was received by theground in amounts shown in Figure 10, weretaken into account, the values of the enhance-ment coefficients were reduced to some extent:this was due to the fact that they added upto the direct radiation from the sun in bothnew and classical greenhouses. However, thisis a useful effect as further increases overall

29


energy gain. There is also an ironing out effectexpressed in terms of the ratios between peakand average insolations. Finally, the presentedtheory can be used to calculate the expectedeffects of the reflecting wall at any particularlatitude, under different weather conditions,and when the average numbers of clear daysare taken into account. Thereby an assessmentof the cost of a particular setup can be obtained.Under circumstances of a few clear days, itmay still be worthwhile from a financial pointof view to turn a classical greenhouse intoone with a reflecting wall by simply coveringthe glass wall on the north-facing side withaluminum foil with virtually negligible expen-diture.

Relative HumidityAir humidity is measured as a percentage ofwater vapour in the air on a scale from 0% to100%, where 0% being dry and 100% beingfull saturation level. The main environmentalcontrol factor for dust mites is relative humid-ity. The followings are the practical methodsof controlling measures available for reducingdust mite populations:

• Chemical control.

• Cleaning and vacuuming.

• Use of electric blankets, and

• Indoor humidity.

X. Conclusions

Thermal comfort is an important aspect of hu-man life. Buildings where people work requiremore light than buildings where people live.In buildings where people live the energy isused for maintaining both the temperature andlighting. Hence, natural ventilation is rapidlybecoming a significant part in the design strat-egy for non-domestic buildings because of itspotential to reduce the environmental impact

of building operation, due to lower energy de-mand for cooling.

A traditional, naturally ventilated buildingcan readily provide a high ventilation rate. Onthe other hand, the mechanical ventilation sys-tems are very expensive. However, a compre-hensive ecological concept can be developedto achieve a reduction of electrical and heat-ing energy consumption, optimise natural aircondition and ventilation, improve the use ofdaylight and choose environmentally adequate

30


building materials. Plants, like human beings,need tender loving care in the form of opti-mum settings of light, sunshine, nourishment,and water. Hence, the control of sunlight, airhumidity and temperatures in greenhouses arethe key to successful greenhouse gardening.The mop fan is a simple and novel air humidi-fier; which is capable of removing particulateand gaseous pollutants while providing ven-tilation. It is a device ideally suited to green-

house applications, which require robustness,low cost, minimum maintenance and high ef-ficiency. A device meeting these requirementsis not yet available to the farming community.Hence, implementing mop fans aids sustain-able development through using a clean, en-vironmentally friendly device that decreasesload in the greenhouse and reduces energyconsumption.

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33


Strategies for the Prevention and (Subsequent)Use of Food Waste from Hospitality and

Restaurant IndustriesAlexander Jager1∗, Douglas Vaught1, Klaus Krennhuber1,

Paul Kuttner2, Dominik Lehner1

1University of Applied Sciences Upper Austria, Franz-Fritsch-Strasse 11, 4600 Wels, Austria2Business Upper Austria Hafenstrasse 47-51, 4020 Linz, Austria

Abstract

1.3 billion tons of food is wasted annually all along the production chain (FAO,2011) and by consumers. This is not only an ethical and an economic challengebut it also deprives the environment of its limited natural resources. The EUseeks every opportunity to prevent food waste and to improve the sustainabilityof the food system. All stake holders in the food chain have a role to play inpreventing and reducing food waste, from those who produce and process foods(farmers, food manufacturers and processors) to those who make foods availablefor consumption (hospitality sector, retailers) and ultimately the consumersthemselves. The reuse and energetic conversion of food waste from the foodservice and hotel industry has grown in recent years.Currently, little precisedata exist on food waste generation by restaurants and hotels. Without accuratedata on where (e.g. kitchen or customer) and how much food is wasted, it isnearly impossible to generate strategies for its reduction. We examined differentestablishments in Upper Austria (restaurants, hotels and commercial kitchens)and determined that the food waste was sorted into 5 different categories with 9fractions each. The amount of unavoidable waste per guest ranged from 20 g to320 g, which shows an enormous saving potential for individual establishments.Based on this data, the CO2 equivalent, water consumption and land use causedby wastage was calculated. Additionally, different approaches on how food wastecan be reduced are described.

Keywords: Food waste, restaurants, hotels, commercial kitchens, sorting,fractionation


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The global volume of food wastage peryear is estimated at 1.6 billion tonnes of’primary product equivalents’.Total food

wastage along the value chain for the ediblepart of this amounts to 1.3 billion tonnes (FAO,2013). In Europe, between 30 and 50% of thefood is lost between field and plate. This rep-resents approximately one third of the foodconsumed. One of the most cited publicationson food waste generation along the productionchain is the review of Bartle et al., (2003), inwhich he claims that half of the food producedis lost before and by the time it reaches the con-sumer. In Austria alone a country of only 8.9million inhabitants-the amount of food waste is1 million tons per year, 300,000 t in households,250,000 t in the hospitality and restaurant in-dustries, 100,000 t in food trade and food retailand 350,000 t in agriculture and food produc-tion (orf.at, 2015). Enormous quantities of re-sources (land, water, energy and fertilisers andinput materials) are wasted and CO2 emissionsproduced. It is noticeable, that industrialisedand developing countries are similar in the pro-portion of food waste generated, varying onlyby where the losses occur (FAO, 2013). Thistopic has only been a topic for discussion inAustria since the turn of the millennium. Be-fore, it was more or less ignored or deemedirrelevant (Lebensministerium.at 2011).

The financial aspects of food wastage alsohave to be considered. In the United King-dom 8.3 million tons of food with a value of14 billion Euros are disposed of annually. Thiscorresponds to 25% of the available food and aCO2 equivalent of 20 million tons. The studyof Creedon et al. (2010) confirms the value of25% for the United States. This represents atotal waste of 90-100 billion Euros, roughly thefinancial cost per ton of food of âCn 2,000. In

addition, the reduction of food waste is an im-portant aspect in the struggle against starvationand poverty (EngstrÃum & Carlsson-Kanyama,2004).

Fig. 1 shows the individual phases and pos-sible reasons for the formation of food waste.One major aspect is loss on the part of theend consumer. In our study, we evaluated thefood loss in hotels, restaurants and canteens,as these count toward loss by end consumers.

Fig. 2 shows that food waste is gener-ally classified into 3 categories (Barthel, Mac-naughton, & Parfitt, 2010):

• Avoidable: food and drink thrown awaythat was, at some point prior to disposal,edible in the vast majority of situations.

• Possibly avoidable: food and drink thatsome people eat and others do not (e.g.bread crusts), or that can be eaten whena food is prepared in one way but not inanother (e.g. potato skins).

• Unavoidable: unavoidable-waste arisingfrom food preparation that is not, andhas not been, edible under normal cir-cumstances.

As a first step in improving the situationby obtaining more accurate data on the typeand quantities of food waste production in thefederal state of Upper Austria, we conducted asurvey about the avoidable and possibly avoid-able food waste in the gastro sector (hotels,restaurants and commercial kitchens). We ex-amined 5 groups of food and separated theminto 9 fractions. This method may be regardedas the most accurate system for the analysisof food waste in the hospitality and restaurantindustries worldwide.

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36


I. Materials and Methods

All food waste was separated into 4 groups offood: Loss made during preparation, food pre-pared but not sold, leftovers from buffets andleftovers on plates. These four food groupswere separated into 9 fractions: Fish meat,vegetables fruits, salad, soups, carbohydrates,sweets and desserts, beverages, dairy productsand additional (i.e. any remaining) food waste.Losses made during preparation were not sep-arated into fractions. Thus, 37 single fractionswere collected as a whole during the surveyat the different businesses. The surveys beganwhen the staff started to work and ended 1 to2 hours after kitchen close. Therefore, 2 shiftsof 2 to 3 examiners were engaged per businesssurveyed. Each shift of examiners consisted

of at least one scientist and one trained stu-dent. Waste quantity was related to the massof meals and beverages issued and the numberof guests. All raw products and all 37 fractionsof food waste were collected and weighed withlaboratory scales (see Fig. 3).

Avoidable food waste per capita and daywas calculated as total food waste per kitchendivided by number of guest per day. The dataset of the surveys was supplemented with ex-isting data sets from prior surveys based on ex-aminations made by United Against Waste, Vi-enna and the University of Natural Resourcesand Life Sciences, Vienna, Hrad et al., (2016).

The usage of agricultural land was calcu-lated as shown by Wohner, (2015) using specificvalues per fraction of food waste (Table 1).

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II. Results and Discussion

We made a precise evaluation of the type andquantities of food waste in restaurants, hotelsand commercial kitchens in the region of Up-per Austria. We collected 5 groups of food andseparated them into 9 fractions. The findingswere supplemented by findings of Hrad et al.,(2016). Based on this data, the CO2 equivalent,water consumption and land use caused bywastage were calculated in addition to thefinancial losses.

Waste generation according to groups andfractionsIt was shown that the amount of food wastewhich is classified as avoidable is in a rangeof 10.4% (canteens and commercial kitchens)and 48.4% (restaurants and hotels). The big

differences can be explained by the higher pro-portion of convenience food in canteens andcommercial kitchens. During the surveys, bigdifferences were also observed in the handlingof preparation waste (e.g. potato peelings). Apositive example is the use of (washed) veg-etable peelings as soup vegetables. High peel-ing losses (either due either to high stress orinsensitivity to waste issues) were negative ex-amples.

Leftovers in gastronomy (28.9%) and com-mercial kitchens (58.4%) represent the biggestarea with regard to avoidable food waste.In the hospitality industry (hotels, inns etc.)dishes not served (19.9%) and leftovers onplates (18.5%) are dominant. Of the caterersexamined, leftovers at buffets (which are notallowed to be reused) dominated with 55% (seeFig. 3).

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When looking at the 9 different food wastefractions, a similar picture emerged (Fig. 4). Inthe hospitality industry, carbohydrates amountto 16.8%, additional food waste 6.6% (sauces,marinades, eggs), vegetables and fruits 15.4%and salad 15.2%. In restaurants, the propor-tions are shifted towards starch & satiatingsupplements at 21.7%. The proportion of fishand meat waste is significantly higher at 15%.In commercial kitchens (e.g. canteens, hos-

pitals, old-age person’s home) soups (23.8%)and starch & satiating supplements (19.8%)represent the biggest part of food waste. Incontrast, the fraction of soups is considerablylower (14.2%) in accommodation services andrestaurants (9.3%). In one commercial kitchen,the proportion of soup waste was very lowat only 6%. This could be explained becausethis specific commercial kitchen prepared theirown soups and did not use instant soups.

Avoidable quantity of waste and savingspotentialAvoidable food waste per capita, excludingpreparation waste and unfinished beverages,are in the range of 90 und 320 g in accommo-dation services, in restaurants between 20 und190 g (� 80) in commercial kitchens between 50-270 g (� 220) (own analysis for total Austria).It is worth mentioning that extremely high andlow values may be coincidental, for example,

on days with very high or low guest numbers.However, extremely high values represent anenormous saving potential. Extremely low val-ues, on the other hand, were observed overseveral days and at several institutions, alsorepresenting a saving potential.

Converting the potential savings to usageof agricultural land would mean a savings of1.3 (restaurants), 2.7 (accommodations) und 7.1ha per commercial kitchen and year. Calcu-

39


lating the saving potential as equivalent CO2,the savings varied between 9 t (restaurants),21 t (accommodations) und 52.7 t (commer-cial kitchen) per year and institution. For theregion of Upper Austria, with 1.45 million in-habitants, this would equal a savings of 12,000km2 and 16,570 t CO2 equivalents annually.

Massive differences in saving potential were

shown when comparing individual enterprises.For example, the daily saving potential rangesfrom a few Euros up to more than âCn 100 perday or âCn 90 cents per day and guest (see Fig.6). In summary, it was shown that the amountof food waste which are classified as avoidablerange from 10.4% for canteens and commercialkitchens to 48.4% for restaurants and hotels.

Our results confirm the findings of Hradet al. (2016). They examined 50 enterprisesfrom all over Austria with the same examina-tion methods. Food waste varied from 6 to 50%per enterprise. The highest percentages variedin commercial kitchen where institutional prob-lems in combination with the insensitivity tofood waste on the part of individuals intensifythe losses.

Nevertheless, on the basis of the data avail-able and the observations made the followingstatements can be made:

The handling of food and food waste varieswidely from kitchen to kitchen and from mas-ter chef to master chef. Nevertheless, we mayconclude from the survey that there is a huge

potential for the reduction of food waste.

It should not be expected that a reductionof food waste on par with ’best cases’ is alwayspossible. However, by implementing even sim-ple measures waste generation and materialinput can be reduced. The value (in terms ofcosts) and the quality of the food has no in-fluence on the quantity of the avoidable foodwaste. Higher quantities of avoidable foodwaste always result in higher input of mate-rial and therefore in higher costs. Higher costsare compensated for in savings in personnel orpassed on to the customer.

Leftover beverages (from the glasses of theguests) and dressings (from the plate and thebuffet) are unavoidable, but in larger busi-

40


nesses and institutions they could be exploitedenergetically.

The following points have been identifiedas the most problematic and improvable: Thepossibility of planning for the number of guests(even in large canteens) has not been fully ex-ploited. Software-based forecasting tools, com-parable to those used in supermarkets, couldbe used to limit the amount of waste gener-ated. In the hospitality industry alone, foodoverproduction due the lack of planning forthe number of guests poses the highest risk.Taking into account the increasing number ofadvanced online bookings, planning should bemore accurate. Efforts to offer all dishes fromthe menu until the closing of the kitchen alsocontribute to overproduction and should bereconsidered. The portion size and the descrip-tion of the meals should be reviewed to avoidleftovers on plates. Sauces, like ketchup andmustard, should be placed on the table andnot be portioned on the dishes. At buffets, theintroduction of additional fees for returningfull plates and dishes should be discussed. Theleftovers from food preparation (peels, meat

pieces and similar) can be used for soups andsauces.

In summary, we conclude that the methodapplied herein for the determination of woodwaste may be regarded as the most accuratesystem in the hospitality and restaurant indus-tries to date worldwide. It enables a preciseanalysis and gives evidence as to the placesand the situations where and when waste isgenerated. Only then, can advices concerningconsequences and countermeasures for eachspecific place be given. A significant marginin the fluctuation shows that there is an enor-mous potential for improvements. Best practiseenterprises show that it is possible to make ded-icated use of the natural resource food. Never-theless, general conclusions can be drawn andshould be followed up by training measures forhotel, restaurant, canteen kitchen and cateringstaff.

Vital resources such as money and watercan also be saved. Simultaneously, the climatefootprint can be improved by the reduction ofCO2 equivalents. Savings of up to âCn 90 centsper meal are possible.

III. Acknowledgements

The project ’Lebensmittelabfallvermeidung in Gastronomie und Hotellerie’ was funded by theFederal State Government of Upper Austria. Many thanks to Landesrat Rudolf Anschober. Wealso thank Andreas Zotz, MSc (United Against Waste, Vienna) and the University of NaturalResources and Life Sciences of Vienna for the excellent collaboration and providing the schemefor food waste sampling.

References

[1] Barthel, M., Macnaughton, S., Parfitt J., 2010. Food waste within food supply chains: quantifi-cation and potential for change to 2050. Philosophical Transactions of the Royal Society B,S.3065-3081.

[2] Creedon, M., Cunningham, D., Hogan, J., 2010. Food Waste.

[3] Engstrom, R., Carlsson, A., 2004. Food losses in food service institutions Examples fromSweden. in: Food Policy, Edward F Coyle pp 203-213.

[4] FAO, 2013. Food wastage footprint, Impacts on natural resources. Summary p 11 ISBN 978-92-5-107752-8.

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[5] Hrad, M., Ottner, R., Lebersorger, S., Schneider, F., Obersteiner, G., 2016. Vermeidung vonLebensmittelabfall in Gastronomie, Beherbergung und Grosskuchen-Erweiterung weitereBetriebe’ Endbericht im Auftrag von Tatort nachhaltige Projekte GmbH, Wien, Osterreich, 35.

[6] Orf.at. (18. Mai 2015). 1.000.000 Tonnen Essen landen im Mull. News orf.at. (accessed Mai 192015 http://orf.at/stories/2279762/2279169/).

[7] Lebensministerium.at 2011. Federal Waste Management Plan 2011 Editor: Bundesministeriumfur Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft

[8] Wohner, B., 2015. Umweltauswirkungen durch Lebensmitterverschwendung in der Ãusterre-ichischen Gastronomie. Accessed Feb 19 2017.

[9] WRAP, 2009. Household food and drink waste in the UK. Banbury, UK. ISBN: 1-84405-430-6.

42


Quality Attributes of Apple Slices Coatedwith Mixed Hydrogel for Shelf Life Extension

Sibel Uzuner1∗, Guler Bengusu Tezel2, Gulsun Akdemir Evrendilek1

1Department of Food Engineering, Faculty of Engineering and Architecture,Abant Izzet Baysal University, 14280, Bolu, Turkey

2Department of Chemical Engineering, Faculty of Engineering and Architecture,Abant Izzet Baysal University, 14280, Bolu, Turkey

Abstract

Fresh-cut apple slices are deteriorated by microbial growth and chemical reac-tions (i.e. browning reactions) very easily. Edible coating is an alternativemethod to extend the shelf-life of fresh and minimally processed fruits andvegetables such as fresh cut produce. The objective of the present study wasto determine the effect of edible coating hydrogel prepared from gelatin andcarboxymethyl cellulose (CMC) on quality changes of fresh-cut apple slicesduring storage at 4 ◦C and 13 ◦C for 4 days by means of color values, browningindex(BI) and total color change(∆E*). Two different type of fresh-cut appleslices coated with hydrogel contain gelatin (1%) and CMC (1%) showed delayedbrowning reactions compared to the control samples. ∆E* values of GoldenDelicious type apple slices for mixed hydrogel coating were lower than thatof the uncoated apple slices. BI for control and for the Golden Delicious typesamples stored at 4 ◦C and 13 ◦C were 24.34, 32.88 and 31.75%,respectivelyfor 24 h. Browning was delayed ca 33.7% by coating, as compared to uncoatedGranny Smith apple slices stored at 13 ◦C after 96 h.These results suggestedthat hydrogel coating can be used for maintaining the quality of fresh-cut appleslices in cake for pastry industry.

Keywords: CMC, edible coating, hydrogel, gum, gelatin, browning

Fresh cut fruits have a very short shelf lifesince they are highly prone by chemicaland microbiological spoilage (Sousa Gal-

lagher and Mahajan, 2011). There are severalpreservation techniques of fruits including coldstorage, acid application, modified atmospherepackaging (MAP) with the traditional ones of

jam making, canning and drying (Morris, 1946).The most important attributes of fresh fruits forconsumers are flavour and appearance, as wellas their nutritional value (Velickova et al., 2013).In addition to consumer demands, there is acurrent interest in the biomaterial applicationof using edible coatings due to extending the


43


shelf-life of fresh cut fruits such as minimallyprocessed fruits and vegetables (Qi et al., 2011).Edible coating can be used as semi-permeablebarrier to allow moisture, gas exchange andrespiration of fruits and vegetables (Qi et al.,2011). Edible coatings, a substitute for syn-thetic plastic, are also used for preservationof several fruits such as mango, kiwi, grape,apple, pear, pumpkin and banana (Kittur et al.,2001). Coating materials for foods can be for-mulated from lipids, proteins, polysaccharidesor any combination of these.

Gelatin, source of protein, is used as anedible coating due to its excellent functionalproperties such as being a good gas barrier andtransparency (Cao et al., 2007). On the otherhand, lower thermal stability and weak me-chanical properties of gelatin restrict its usageduring processing.

Thus, film forming properties of gelatinshould be improved by using it in mixedbiopolymer films (Gomez-Esaca et al.,2011).The combination of gelatin with otherbiopolymers such as whey protein (Taylor et al.,2014), starch (Fakhouri et al., 2015), chitosan(Benbettaieb et al., 2016) could improve its me-chanical properties. Carboxymethyl cellulose(CMC) is one of the most abundant material,easily processed and inexpensive (CMC),andit is the most used coating materials due pro-viding an increase in both viscosity and waterbinding properties (Biswal and Singh, 2004).Aguilar-Mendez et al. (2008) found that theapplication of gelatin-starch coatings extendedthe postharvest shelf life of avocado.

There are few studies on the hydrogel coat-ing materials as well as on the colour behaviourof hydrogel coated apple slices to comparechromameter and RGB model. Therefore, theobjective of this study is to enhance modifiedgelatin (increasing gel formation of gelationwith CMC) as a coating materials for fresh-cut apple slices in terms of colour parameters.The present study also determines the effect ofhydrogel coating on colour parameters and ap-pearance of fresh cut apple slices in addition toevaluation of modelling based on color values.

I. Material and Methods

MaterialsPolymer powders of gelatin and sodium car-boxylmethyl cellulose (CMC) (Benosen Foodand Chemical Company, Istanbul, Turkey),with nominal molecular weight of 700.000g/mol were kindly provided by Dr. Gulsun A.Evrendilek, from the Department of Food En-gineering, Abant Izzet Baysal University (Bolu,Turkey).The ’Golden Delicious’ and ’GrannySmith’ apples were purchased from a localmarket in Ankara, Turkey.

Preparation of coating materialThe CMC and gelatin powders were dissolvedin distilled water at 40 ◦C for 6 husing a mag-netic stirrer with gentle shaking in order toprepare 1.0% (w/v) stock solutions of CMCand gelatin, separately. Based on prelimi-nary experiments, the range of the variables(gum concentration, gum ratio, pH and tem-perature) for gel strength was selected andoptimized.CMC and gelatin stock solutionwere thoroughly mixed to form a solution at2:1 (v/v) ratio of gelatin:CMC and pH 7.0.

Coating applicationThe coating material was prepared by mixtureof gelatin and CMC. Gum solution (100 mL)was mixed with a magnetic stirrer for 30 min.Golden Delicious and Granny Smith type of ap-ples were halved and then cut into slices. Then,the apple halves were subsequently dippedto the coating material for 3 min to minimizeundesirable reactions. The apple slices werekept at both 4 and 13 ◦C for 4 days which wasthe optimal point of gel strength before thecolour measurement.

Colour measurementThe colour of the apple slices after coating wasmeasured using chromameter CR-400 (KonicaMinolta, Osaka, Japan). The L* (lightness), a*(redness) and b* (yellowness) values were mea-sured and used for the calculation of colourparameters listed below:

The hue angle, defined as ho=tan−1 (b/a)

44


was calculated from a* and b* values and ex-pressed in degrees of 0o (red), 90o (yellow),180o (green) and 270o (blue).

The total color difference (∆E):

where Li, ai, bi, were the initial colour val-ues of fresh apples and L f , a f , b f , were thevalues of colour parameters after coating (Ihnset al, 2011; Mohammadi et al, 2008).

Color changes in RGB measurement wasalso performed by using image analysis. Pro-gram automatically calculated the average per-centage of red (R), green (G) and blue (B) colorson a sample area. The hue angle defined as:

(3)

Colour changes (∆E) in RGB were definedas:

(4)

where ∆R, ∆G and ∆B were differencesbetween colour values of uncoated and coatedapple slices.For all color data, average of fivemeasurements were used for high precision.

Statistical analysisOne-way analysis of variance (ANOVA) andpairwise comparisons which were made byTukey’s test were evaluated with a significancelevel of 0.05 using MINITAB 16 (Minitab Inc.).


Colour is the most important visual attributesof fruits. Colour measurement can be classi-fied into two groups: visual analysis of the red,green and blue (RGB analysis) and instrumentanalysis (L*, a* and b* analysis). L*, a* and b*values of Golden Delicious and Granny Smithtype of sliced apples were measured before andafter coating at both 4 and 13 ◦C with mixedhydrogels and their model conversions to thered, green and blue are also presented in Ta-ble 1. Pairwise Tukey’s comparisons revealedthat mixed hydrogels coating gave significantlybetter colour values than the uncoated apples(p<0.05).

45


Except for Golden Delicious samples at 4 ◦Cfor 24h, L* values tend to increase in coatedsamples. Colour parameters for coated appleslices stored at 13 ◦C were found better thanstored at 4 ◦C (Table 1). Hue value (ho) wasobserved 44.04o and 43.29o at 13 ◦C during 24hfor Golden Delicious and Granny Smith coatedapple slices, respectively. Colour change val-ues for Golden Delicious and Granny Smithapple slices at 13 ◦C for 24 h were found as8.44 and 6.49, respectively. Hue values forGranny Smith coated apple slices were not

significantly changed (p>0.05) during storage(data not shown), whereas hue values for un-coated apple slices were decreased during stor-age.

Enzymatic browning has occurred in ap-ple slices after cutting. The BI has generallyused as an indicator of browning reactions dur-ing storage (Olivas et al., 2007). Based on BIresults, there was a significant difference be-tween coated apples and uncoated apples atdifferent treatment time (p< 0.05) (Fig.1).

Results revealed that BI increased rapidlyfor the first 72 h in uncoated Granny Smithtype of apple slices (Fig.1). However, BI in-creased for the first 48 h in apple slices coatedwith hydrogel, and then levelled off. Thus,browning reaction occurred in early stage ofstorage. Martinez-Romero et al. (2006) andSong et al. (2013) also reported that Aloe veragel coated apple slices delays browning as com-

pared to the control.Correlation coefficient for colour change

values (∆E) and hue angle (ho) values fromchroma meter and digital analysis with RGBvalues were found as r=0.99 and r=0.987, re-spectively (Fig. 2 and Fig.3). It was foundthat image analysis as well as the colorime-try method can be used to observe the colourchanges on coated apple slices (Fig.2).

46


Consumers’ preference for the selection oftheir food generally based on visual perception.According to colorimetry and digital analysisresults, digital analysis can be used as a visual

perception of coated apple slices. Fig.4 repre-sents uncoated and coated apple slices for 24 hat 13 ◦C.

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III. Conclusions

Gelatin-CMC (blended) solution was appliedas edible coating on fresh cut apple slices asa food model. The mixed hydrogel used tocoat sliced apples provided significantly bet-ter colour values than the uncoated samples

due to acting as a barrier on the surface ofthe apple slices.Evaluation of L*, a* and b* val-ues showed the possibility of the reliable useof this system for determination of absolutecolour values of food stuffs with much lowercost in comparison with chroma meter.

IV. Acknowledgements

Funding for this study was provided by AIBU Scientific Research Project Unit, Grant No: BAP-2015.09.04.933 at the Department of Food Engineering, Abant Izzet Baysal University, Turkey.

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[13] Sousa Gallagher, M.J., Mahajan, P.V., 2011. The stability and shelf life of fruit and vegetables,in Food and Beverage Stability and Shelf Life, D. Kilcast and P. Subramaniam (Eds.), WoodheadPublishing. 641-656.

[14] Velickova, E., Winkelhausen, E., Kuzmanova, S., Vitor, D.A., Moldao-Martins, M., 2013.Impactof Chitosan-Beeswax edible coatings on the quality of fresh strawberries (Fragaria Ananassacv Camarosa) under Commercial storage conditions. LWT-Food Science and Technology, 52:80-92.

[15] Taylor, M.M., Lee, J., Bumanlag, L.P., Latona, R.J., Brown, E.M., 2014. Biopolymers producedfrom gelatin and whey protein concentrate using polyphenols. Journal of American LeatherChemistry Association, 109: 82-88.

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Commercial In-line or Continuous MicrowaveProcessing of Pumpable Shelf-Stable


David L Parrott∗

Industrial Microwave Systems, LLC, 3000 Perimeter Park Drive, Morrisville, NC 27560, USA

Abstract

Although the batch microwave oven has become an accepted means of heatingfood throughout the world, and commercial planar belt microwave pasteurizersand sterilizers have been used for many years in Europe to produce pre-packagedentrees or ready meals, it is only recently that microwave heating has beensuccessfully applied to pumpable shelf-stable food products on an in-line orcontinuous commercial basis. This paper reviews and compares the progressthat advanced thermal heating technologies have made in global food processingduring the past thirty years, with particular emphasis on ohmic, radio frequencyand microwave applications. An example of the successful collaboration betweenthe US government, academia and the private sector is presented where thenovel use of rapid uniform microwave heating was able to turn a large sourceof agricultural product that could not be sold in the retail market into a highvalue food ingredient containing no additives. This was the first commercialcontinuous microwave heating process approved by the US Food and DrugAdministration (FDA) for pumpable low acid shelf-stable foods, and initiatedthe creation of several new agricultural products that have replaced traditionalingredients used by major beverage, bakery and baby food processors. Followingadditional product development studies, the technology was recently exportedto the Netherlands and is now available for customer trials in Europe. Recentapplications by academia and industry have led to an expansion in the use of thistechnology for microwave assisted extraction (or MAE) of various biomaterialsthat indicate the potential for new value added products in the pharmaceuticalarena.

Keywords: Advanced thermal processing, continuous microwave, microwaveassisted extraction, shelf-stable foods, US FDA.


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Commercial batch microwave ovens havebeen used for heating food worldwidefor several decades, but the same cannot

be said for continuous food processing systems.European companies such as Top’s Foods NVin Belgium sterilize or pasteurize more than60,000 pre-packaged meals per day using mi-crowave systems originally designed by OMACItaly in the 1980’s, but this success has yet to berepeated in Asia or the Americas. Reasons forthis include lack of equipment suppliers, lim-ited vendor sources for key components, gov-ernment regulations on process and equipmentuse, insufficient emphasis on safety issues, andin particular non-uniformity of microwave en-ergy distribution. It was only in 2008 that theUS Food and Drug Administration (FDA) ap-proved the use of continuous microwave pro-cessing for pumpable shelf-stable non-acidifiedlow acid foods (pH >4.5), and the first US com-mercial microwave sterilizer for pre-packagedmeals will only be fully operational later thisyear.

Microwaves are just one of several non-radiation advanced thermal processes that canreplace conventional hot surface heaters infood processing. The APV Company, nowpart of the SPX Group, obtained a license from

the UK Electricity Council in the 1980’s to de-velop a process using ohmic heating for thecontinuous sterilization of pumpable foods,and sold over thirty commercial systems world-wide. This 50/ 60 Hz electrical resistance heat-ing method relies on the passage of an electriccurrent that passes through the food productas it is pumped through the heater. AlthoughAPV had consistent success with high acid fruitproducts where the electrical resistive charac-teristics of particulates and carrier fluid are vir-tually identical as the heating profile changes,the technology was much more difficult to ap-ply with low acid products, particularly thosecontaining fats and oils that act as electricalinsulators.

Considerable time and effort was spentwith customers reformulating their recipes toreduce the difference in heating rates betweenthe carrier fluid and individual particulates.With ohmic heating, even water requires theaddition of an electrically conductive ingredi-ent, such as salt, before it heats. The technologywas first commercialized in the USA in 1994when it was combined with the ’Flash 18’ ster-ilization process to thermally process a rangeof canned low acid recipes for the food serviceindustry.

Since then other equipment suppliers havereduced the electrode material cost, improvedthe electrode housing design to minimize

trapped particulates and product burn on, aswell as the use of higher operating frequenciesand faster response control systems to reduce

51


product electrolysis. Some have even combinedohmic with microwave technology.(David et al.,2013). However, worldwide acceptance usingcommercial ohmic heating for the productionof pumpable foods has been slower than origi-nally anticipated.

Both radio frequency (RF) and microwavesare forms of energy within the electromagneticspectrum, shown in Figure 1. RF applies a volt-age to a pair of electrodes creating an electricfield in the space between them through whichthe food product is pumped and heated. Theseelectrodes may also form or mold the product

during heating. In the early 1990’s, APV devel-oped a RF cooker in collaboration with TulipInternational AS Denmark, a leading companyin the production of pork meat products.

Despite this, and the long term efforts ofCompanies such as Strayfield PLC to mar-ket their tubular heaters, RF has not achievedmuch commercial success with pumpable foodproducts. Many of the issues associated withusing ohmic and RF technologies in continuousfood processing have been resolved when con-sidering microwaves. A comparison of theseelectro-heating technologies is given in Table 1.

I. The IMS Continuous Microwave

Heating System

Conventional heat exchangers, such as shell-and-tube, plate-and-frame, and scraped sur-face, use a combination of conduction andforced convection to achieve heat transfer overtime. A heating medium, usually steam or

hot water, conducts heat through a metal sur-face that then transfers it to a pumped processfluid, which may or may not contain particu-lates. Since the fluid velocity is slower at thewall surface than the center of the plate or tube,the process fluid in contact with the wall maydegrade or burn as a result of longer contact

52


time with the hot surface.In the late 1990’s, Industrial Microwave Sys-

tems, LLC, (IMS) developed a single mode fo-cused in-line heating process that does not relyon a hot heating surface. Microwave energyexcites the polar molecules (typically water)throughout the entire volume of a food prod-

uct, and the result is an extremely fast heatingprocess. This, combined with the lack of ahot heating surface, minimizes product heatexposure and physical degradation which max-imizes its quality. A typical IMS system forpumpable foods is shown in Figure 2.

The three major components of the systemare the 915 or 2,450 MHz generator or transmit-ter, the applicator which is designed to focus100% of the microwave energy into a cylin-drical space occupied by a Teflon or ceramicproduct heating tube, and a wave guide as-sembly that connects the generator(s) to theapplicator(s). The product temperature exit-ing the uppermost applicator in this design isconstantly compared to the required set pointtemperature in the PLC control system thatregulates the microwave power output fromthe generator to minimize variation to +/- 1.5degrees Celsius or better. Applicators can bearranged either in series,parallel, (or a com-bination of both),to minimize the production

footprint of high capacity systems.

II. Commercialization for


After patenting its equipment design in thelate 1990’s, IMS recognized it would need as-sistance in commercializing it for the US foodprocessing industry. It was fortunate to be lo-cated close to the Department of Food Scienceat North Carolina State University (NCSU),a founding member of the US Center forAdvanced Processing and Packaging Systems(CAPPS) for the food industry, as well as theSouth Atlantic Agricultural Research Service

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of the US Department of Agriculture (ARS).IMS teamed up with NCSU and ARS, and thisconsortium jointly tested over twenty fruit andvegetable purees, with prime focus on NorthCarolina grown orange sweet potato. In con-junction with NCSU and ARS, IMS developedand owns process patents for the rapid steril-ization of pumpable foods and biomaterials byexposure to electromagnetic energy.

North Carolina has historically been a ma-jor grower and supplier of tobacco. The 1990’shad seen a national movement against the USconsumption of tobacco resulting in expensivelegal law suits against the cigarette companieswho marketed their products. This allowed to-bacco growing states to provide financial incen-tives to their farmers to replace tobacco withother cash crops such as blueberries and sweetpotato.

By 2003, just seven agribusiness ownersmanaged and harvested approximately 50% ofthe total North Carolina crop, but were plough-ing back over 40% of their yield as less thanperfect for the seasonal fresh retail market. Af-ter a presentation of the IMS technology, theowners immediately realized it had the possi-bility to produce a natural high value addedshelf-stable functional food ingredient that wasnot available at that time, but could be mar-keted for pet food, baby food, baked goodsand beverage products.

The owners joined together as a consortiumand Yamco LLC was formed in 2004. (Par-rott, 2010). With the assistance of the USDAand several North Carolina State grants, Yamcopurchased a manufacturing facility in 2006 andhad it converted into a state-of-the-art facil-ity devoted to the production of asepticallyprocessed and packaged pumpable vegetablepurees.

An intense research program was under-taken to demonstrate and validate both the mi-crowave heating process and bag-in-box pack-aging system to produce shelf-stable sweetpotato puree samples that were periodicallytested for quality and bacterial growth overa two year period. The result was the filingof several process patents jointly held by IMS,

NCSU and ARS based on use of the cylindricalmicrowave heater.

Also in 2006, Yamco funded sensory panelstudies at NCSU that conclusively demon-strated sweet potato purees processed in theIMS cylindrical heating system were on a parwith freshly made purees, and clearly preferredby consumers over conventional tubular asep-tic, frozen and canned purees (Drake and Yates,2006).

The 94% retention of the raw beta carotenecontent after microwave sterilization confirmedby the NCSU/ ARS studies was thought to bedue to two major effects: firstly, the low overallexposure of product to microwave heating min-imizes destruction of the heat sensitive betacarotenes or Vitamin A.

In addition, the yield or extraction of thecarotenes from the processed matrix of sweetpotato flesh is greatly enhanced when fol-lowed by microwave sterilization, known asMicrowave Assisted Extraction or MAE (CRCPress, 2009).

The success of the sensory trials led toYamco purchasing its first microwave heater,and by April 2008 the FDA issued a letter ofnon-rejection allowing Yamco to process andmarket their aseptic sweet potato puree com-mercially.

IMS, NCSU and ARS received two awards:the 2009 Institute of Food Technologists’ FoodTechnology Industrial Achievement Award rec-ognizing the success of the first FDA acceptedinstallation to use microwave processing forproduction of a low acid product (Brody 2009),and the 2009 USDA Agricultural Services’ Tech-nology Transfer Award, which recognizes con-tributions in advancing North American agri-culture.

Each year since initial production, the con-sortium has expanded to process other lessthan perfect seasonal vegetable products thatotherwise would be discarded. These includebutternut squash, pumpkin, carrot and spinach.Two years ago, Yamco installed its second IMSmicrowave heaters (Figure 3) to meet increas-ing demand for its aseptic low acid vegetableproducts.

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The North Carolina State University re-searchers realized that the sensory and nutri-tional benefits obtained with the microwavesterilized orange sweet potato puree couldbe applied to other heat sensitive agriculturalproducts and found similar benefits when asep-

tically processing purple sweet potatoes (Steedet al, 2008).

Since the color, anthocyanin and anti-oxidant components of these products could belargely preserved, IMS realized that the tech-nology could be applied to developing newshelf-stable berry fruit products that are stillunavailable. As an example, strawberry pro-cessors in Florida typically harvest and mar-ket their fresh product from late Decemberthrough early March but cannot compete onprice once the crops in California are available.The result is at least one third of fresh Floridaproduction is wasted and ploughed back intothe soil each year.

As the joint process patent holders pursuedfurther research projects at NCSU and ARS,IMS decided to team up with the Departmentof Food Science at Purdue University in Indi-ana and industrial food processors to developnew fruit and vegetable products. These in-cluded sensory, nutritional quality and shelf-life studies, not only for a variety of low acidshelf-stable vegetable purees and particulatefoods, but also high acid sliced and diced fruitsas detailed in Table 2.

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III. Future Food and Biomaterial

Applications

As well as developing economic and case stud-ies to justify investment in its technology, IMSoffers customers the ability to develop andtest pumpable food products at Purdue Uni-versity in the USA. Last year, it initiated apartnership with SELO in the Netherlands,www.SELO.com, where an IMS in-line mi-

crowave heating system has been installed forcustomer trials in Europe. With the advantagesof MAE, overproduced or waste agriculturalcrops can be converted into new profitable andnutritious food ingredients using this technol-ogy. In addition, commercial success has alsobeen achieved with a variety of biomaterialand pharmaceutical applications, including nu-traceuticals from plant extracts, and cellulose& other casings for protein emulsions.

References

[1] Brody, A., 2009. Aseptic Packaging 2009. Food Technology, 63(7): 71.

[2] CRC Press, 2009. Extracting Bioactive Compounds for Food Products, Theory and Applications.Edited by M. Angela A. Meireles. Pp. 151-155.

[3] David, J.R.D., Graves, R.H., Szemplenski, T., 2013. Handbook of Aseptic Processing andPackaging. Second Edition, CRC Press.

[4] Drake, M., Yates, M., 2006. Consumer Sensory Analysis and Descriptive Analysis of PureedSweet Potatoes. North Carolina State University, July 12. Private Communication.

[5] Parrott, D.L., 2010. Microwave Technology sterilizes Sweet Potato Puree. Food Technology,64(7): 66-70.

[6] Steed, L.E., Truong, V.D., Simunovic, J., Sandeep, K.P., Kumar, P., Cartwright, G.D., Swartzel,K.R., 2008. Continuous Flow Microwave-Assisted Processing and Aseptic Packaging of Purple-Fleshed Sweet Potato Purees. Journal of Food Science 73(9): 455-462.

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Improvement of the Techno-FunctionalProperties of Pea Proteins by

MicrofluidizationOliete, B., Cases, E., Saurel, R.∗

Univ. Bourgogne Franche-Comte, AgroSup Dijon, PAM UMR A 02.102, F-21000 Dijon, France

Abstract

The use of pea (Pisum sativum (L.)) proteins in the food industry is still limiteddespite their good environmental sustainability, heath-oriented composition,reliable origin and stable price. However, one of the most important limitationsis their low solubility which determines a number of their techno-functionalproperties. Microfluidization is a non-thermal emerging technology that maymodify the structure and the techno-functional properties of pea proteins. Mi-crofluidization combines high shear forces due to the stream speed and direction;impact forces from collisions with the walls and with the fluid itself; and turbu-lence inside the chamber. The objective of this work was to evaluate the effects ofdynamic high pressure (microfluidization) on the techno-functional propertiesof commercial pea protein isolates. Microfluidization was performed by usinga Microfluidizer processor model LM10 (Microfluidics, Newton, MA, USA)provided with a Z-type chamber. Solubility was clearly increased when applyingmicrofluidization at 100MPa. Microfluidization also improved the least gelationconcentration by thermal and acidic treatments, and the interfacial tension.However no clear effect was observed in the foaming capacity. This work per-mitted to conclude that the effect of microfluidization depends on the samplecharacteristics, on the environmental conditions, and on the microfluidizationparameters.

Keywords: Pea proteins, microfluidization, dynamic high pressure, techno-functional properties, solubility

There is a growing interest by includinglegume proteins as ingredient in foodproducts due to their nutritional, envi-

ronmental and economic benefits (Davis et al.,2010). Soy protein is at the moment the mainsource of vegetal proteins; however, there are

other legumes such as pea particularly appeal-ing for protein production.

Pea can be grown extensively worldwideand the hull is easily removed. Moreover, itsuse would decrease the pressure on the sup-ply and availability of soybean and shows low


57


potential for allergic responses. These are thereasons why important companies such as Co-sucra Groupe, Roquette, Vital Greens or Nor-ben have developed innovative pea ingredients(Sirtori et al., 2012). Nevertheless the use ofpea protein in the food industry is far from be-ing optimized. One of their limitations is theirlimited solubility. This fact conditions othertechno-functional properties such as gelation,emulsification, or foaming.

The techno-functional properties of legumeprotein depend on their amino acid compo-sition, molecular structure and conformation.Pea proteins are mainly globulins which areclassified into different groups on the basisof their sedimentation coefficient, being 11S(legumin) and 7S (vicilin, convicilin) the mainfractions. 11S legumins (360-400kDa) are con-stituted by 60 kDa monomers which forms hex-amers in the quaternary structure at pH=7-9.Each monomer is formed by two polypeptides,one acide or α (≈40kDa) and one basic or β(≈20kDa), which remain linked by a disulfidebridge (Tzitzikas et al., 2006).

7S vicilins are smaller (150-200kDa) butmore heterogeneous than legumins. They showa trimeric quaternary structure with 50kDasubunits that would be joined by electrostaticunions (Gatehouse et al., 1982). Finally, 7Sconvicilin is constituted by ≈71kDa subunitsprobably associated in tetramers (Barac et al.,2010). Legumin, vicilin and convicilin confor-mation and structure can be modified by pro-cessing conditions (Boye et al., 2010). In con-sequence the process-induced modificationsof pea proteins may permit the improvementof the physicochemical and techno-functionalproperties of pea proteins.

Novel techniques such as microfluidizationmay modify the structure and the conforma-tion of proteins. Microfluidization or dynamic

high pressures uses high pressures to force aliquid to go through a fixed and small geom-etry. That process creates a combination ofturbulence, shear and impact that may modifyprotein structure. Studies with whey proteins(Dissanayake and Vasiljevic, 2009) have demon-strated the improvement of solubility, emulsi-fying and foaming properties after a heatingtreatment (90 ◦C for 10 min) at pH 7 followedby a microfluidization treatment at 140 MPa .

In the case of soy protein, microfluidizationat 120 MPa resulted in partial unfolding, de-naturation and even structural re-arrangementof the proteins (Shen and Tang, 2012). Thesechanges led to the increase in solubility, sur-face hydrophobicity and exposed sulfhydrylgroups. Hu et al. (2011) have also observedan improvement of solubility and emulsifyingproperties of peanut proteins after microflu-idization treatments between 40 and 160 MPa.

The objective of this work was to analyzethe effects of microfluidization treatment (100MPa) on the techno-functional properties ofthree commercial pea protein isolates. Isolateswere characterized in terms of electrophoreticprofile and thermal transition. Protein solubil-ity, least gelation concentration by both thermaland acidic treatments, interfacial tension andfoaming capacity were analyzed.


MaterialThe three pea protein isolates (PPI) were kindlyprovided by COSUCRA (Cosucra, Warcoing,Belgique). For notation they were named A, Band C. Composition of these powders in termsof dry matter, ashes, total nitrogen, non proteicnitrogen and proteic nitrogen were indicatedin Table 1.

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Microfluidization treatmentPPI dispersions at 12% (w/w) in 10mM phos-phate buffer pH 7 and 0.05% sodium azidewere subjected to microfluidization at 100MPa (A100MPa, B100MPa, C100MPa) in a LM10Microfluidizer (Microfluidics, Newton, MA,USA) fitted with a Z-type chamber. Sampleswere passed through the system 3 times. Thetemperature of the protein solution during themicrofluidization treatment remained under30 ◦C. All the samples obtained were stored at4 ◦C before analysis, and were used within 2weeks.

Differential scanning calorimetry (DSC)The thermal transition of PPI samples wasexamined by DSC using a Micro DSC IIIcalorimeter (Setaram, Caluire, France). Weused 5% (w/w) PPI dispersions prepared in10 mM phosphate buffer pH 7. Approximately0.5 g of sample was weighed in an aluminiumpan, hermetically sealed and heated from 25 to105 ◦C at 0.5 ◦C/min. A pan with 10 mM phos-phate buffer, pH 7, was used as a reference.All experiments were conducted in triplicate.One replicate of each sample was re-heatedafter cooling to check that denaturation wasirreversible.

SDS-polyacrylamide gel electrophoresisThe polypeptide composition of PPI sampleswas studied by SDS-polyacrylamide gel elec-trophoresis (SDS-PAGE) following the method

described by Laemmli (1970). Slab gels werecomposed of 4% (stacking) and 12% (separat-ing) gels (w/v) at pH 6.8 and 8.9, respectively.Protein content was adjusted to a final con-centration of 5 mg/mL in the sample buffercontaining 187 mM Tris-HCl at pH 8.9, 10%glycerol, 2% SDS, 0.05% bromophenol blue(all percentages are expressed in w/v), inthe absence (non-reducing (NR) conditions)or presence of 2% (w/v) dithiothreitol (DTT;reducing (R) conditions). Samples under Rconditions were heated for 10 min at 95 ◦C. Weloaded 20 µL samples in each well. Proteinstandards (wide range, molecular mass 6.5-200kDa, Sigma-Aldrich catalogue No. S-8445)were applied in separate lanes as molecularweight markers. Proteins were separated at 65V until bromophenol blue reached the bottomof the gel. Electrophoretic current was main-tained constant at 20 mA/gel. The gels werescanned using a Molecular Imager ChemiDocXRS + system (Bio-Rad, Hercules, CA, USA).Each sample was analysed in duplicate.

Protein SolubilityDispersions (1% w/w) of PPI samples wereprepared in 10 mM phosphate buffer pH 3, 5, 7and 9, and stirred magnetically overnight. pHwas adjusted after sample addition and afterstirring with 0.5 M HCl or 0.5 M NaOH. Sam-ples were centrifuged at 10,000 x g for 20 minat 4 ◦C. The protein content of the supernatantand the initial dispersion were determined by

59


the Kjeldhal method. Nitrogen soluble index(NSI) was calculated as indicated in Equation1.

(1)

Least gelation concentration (LGC)LGC was calculated by forming a thermic gel(LGC-T) and by forming an acidic gel (LGC-A). For LGC-T, dispersions of PPI samples (3ml) were prepared in 10 mM phosphate bufferpH 7 with concentrations between 6% and15% (w/w), and stirred magnetically overnight.Dispersions were placed in a temperature-controlled water bath previously equilibratedat 40 ◦C, then heated at 1 ◦C/min from 40to 90 ◦C, incubated at 90 ◦C for 60 min, andrapidly cooled on ice for 24h. After that thetubes were inverted. The lowest concentrationat which the sample did not fall down or slipfrom an inverted tubes was considered as theLGC-T (Laval et al, 2005).

For LGC-A, dispersions of PPI samples (10ml) were prepared in phosphate buffer 10 mMpH 7 with concentrations between 1% and10% (w/w), and stirred magnetically overnight.The acid-induced cold gelation was obtainedby adding glucono delta-lactone (GDL). Theconcentration of GDL added to the samplesto induce gelation were determined using theempirical relationship indicated in Equation 2(Munialo et al., 2014).

(2)

Acidification was considered finished whenpH reached stable values (3.8-4.5). In thatmoment, tubes were inverted. The lowest con-centration at which the sample did not falldown or slip from an inverted tubes was con-sidered as the LGC-A.

Interfacial tensionDispersions (1% w/w) of PPI samples were

prepared in 10 mM phosphate buffer pH 3, 5,7, 9. Interfacial tension between protein disper-sions and Miglyol 812 N (OIO Oleochemicals,Hamburg, Germany) oil was determined ac-cording to the Du Nouy ring method using atensiometer Kruss K100 (A.KRUSS OptronicGmbH, Germany); and was compared to theinterfacial tension in the same system withoutprotein (10 mM phosphate buffer pH 3, 5, 7, 9and Mygliol).

Foaming capacityFoaming capacity(FC) was determined as in-dicated by Adebiyi and Aluko (2011). Disper-sions (1% w/w) of PPI samples were addedto phosphate buffer 10 mM pH 7 and 9 andhomogenized at 20,500 rpm for 1 min using 20mm foaming generator on the Ultra-Turrax T25high-speed blender (IKA, Staufen, Germany).The foam was formedin a 50 ml graduated cen-trifuge tube, which enabled determination offoam volume (ml) at room temperature.FC (%)was calculated as indicated in Equation 3.

(3)

Where Vft0 is the volume of foam at t=0and Vl is the volume of liquid.


Differential scanning calorimetryThe study of the thermal behavior of the A,B and C samples by DSC showed that pro-teins were denatured since the obtained ther-mograms (Figure 1) did not show any endother-mic peaks corresponding to the denaturationtemperatures of pea globulins. These temper-atures should be around 68.5 ◦C for vicilinsand 76.6 ◦C for legumins (Mession et al., 2015)in similar measurement conditions. The ex-traction conditions used in industry would beresponsible of protein denaturation.

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SDS-polyacrylamide gel electrophoresisSamples were analyzed by denaturing SDS-PAGE electrophoresis under non-reducing (NR,without dithiothreitol DTT) and reducing (R,with dithiothreitol DTT) conditions. A widemolecular mass electrophoretic profile of sam-ples was observed ranging from 94 to 16kDa. No differences were observed in the elec-trophoretic profile as a result of microfluidiza-tion (Figure 2 a and b), nor between samples.Bands were identified as lipoxygenase (Lox),convicilins (CV), legumins (L), and vicilins (V)(Crevieu et al., 1997; Gatehouse et al., 1980;Shand et al., 2007).

Lox appeared in all samples at approxi-mately 94 kDa as reported by Crevieu et al.(1997) and Mession et al. (2013). CV appearedat about 71 kDa. The band corresponding tothe L polypeptide (Lα β, approximately 60kDa) was only observed under NR conditions.Under R conditions, Lα β was dissociated intoits acid (Lα, approximately 40 kDa) and itsbasic (Lβ1, approximately 24 kDa; and Lβ2,approximately 20 kDa) subunits, because thesesubunits are joined by a disulfide bridge (Gate-house et al., 1980). Four different polypeptides

have been identified as V fractions at about 50kDa (V1), 33 kDa (V2), 30 kDa (V3), and 19kDa (V4), respectively.

Protein SolubilitySolubility is one of the basic techno-functionalproperties of proteins since solubilized pro-teins would mainly affect the other techno-functional properties.

In general commercial isolates showed re-duced protein solubility as a result of the in-dustrial treatments undergone during extrac-tion and conditioning, even at pH far from theisoelectric point (Shen and Tang, 2012). Asexpected we observed that protein solubilitywas minimum close to the isoelectric point ofvicilins (pI 4.5) (Ezpeleta et al., 1996) and theacidic fraction of legumin (pI 4.7) (Krishina etal., 1979). Far from the pI, solubility increasedreaching the highest values at pH 9. Whenmicrofluidization at 100 MPa was applied, sol-ubility notably increased at all pH except atpH 5. In fact, solubility values at high pH val-ues increased 3-5 times after microfluidizationdepending on the kind of sample.

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62


The highest solubility values were obtainedat pH 7 and 9. Shen and Tang (2012) alsoobserved the improvement of native and heat-treated soy proteins solubility after microfluidi-sation at 120 MPa. It seems that microfluidiza-tion would be able to disrupt insoluble aggre-gates into smaller ones that would be soluble(Dissanayake and Vasiljevic, 2009). Differences

between the three samples would indicate thatthe effect of microfluidization is closely relatedto the nature of the applied proteins. Differ-ences in the extraction process such as ionicstrength and particular extraction conditionsinfluencing aggregated state of proteins wouldalso modify the effect of microfluidization.

Least gelation concentration (LGC)The least gelation concentration is the low-est concentration required to form a self-supporting gel. Gel was formed by thermaltreatment (LGC-T, Figure 4) and by acidic treat-ment (LGC-A, Figure 5). The obtained LGC-Tand LGC-A values were in the range of 6-18%as presented by Boye et al. (2010) for variouslegume proteins. In all cases microfluidizationat 100 MPa improved the gelling capacity, that

is, it decreased the LGC values. Differencesbetween samples would indicate the influenceof the sample characteristics and the extractionmethod on the gelling properties.The improve-ment of the gelling capacity would be relatedto improvement of solubility. However our re-sults confirmed the influence of other factorssuch as the ionic strength or the protein aggre-gate conformation, since protein solubility andLGC did not exactly follow the same behavior.

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Interfacial tensionInterfacial tension of protein gives an ideaabout their emulsifying properties. Thediminution of the interfacial tension would in-dicate the adsorption of protein molecules atthe oil/water interface improving the emulsify-ing capacity. Proteins when well dispersed andin solution, generally have good emulsifyingproperties as they can readily migrate to theoil/water interface (Sikorski, 2001). The emulsi-

fying properties of legume storage proteins areessentially determined by their physicochem-ical and conformational properties (Moure etal., 2006). Figure 6 showed the interfacial ten-sion of proteins at different pH. The lowestvalues of interfacial tension were obtained atpH 7 and 9, with slight differences betweenprotein samples. In general, microfluidizationdecreased the superficial tension of proteins.This effect was noticeable at pH 3 but almost

64


inexistent at pH 5. Shen and Tang (2012) alsoobserved the improvement of the emulsifyingability of soy proteins after microfluidization atpH 7 depending on the prior thermal treatmentapplied to samples. These authors indicatedthat the emulsifying properties of proteins de-pended not only on the solubility and surface

hydrophobicity, but also on the flexibility inthe tertiary conformation of legume proteins.Differences between samples A, B and C wereprobably related to differences in the process-ing route of samples as already indicated byAluko et al. (2009).

Foamingcapacity (FC)Foaming properties are decisive in the man-ufacture of foods such as ice cream or cakes.Microfluidization did not show a clear effect onFC of pea proteins: microfluidization increasedFC in one sample (sample A), it decreased FCin another one (sample C), and its effect de-pended on pH in the third one (sample C).However, other studies with soy proteins (Shenand Tang, 2012) evidenced an increase in FCafter microfluidization. These authors justified

their observations by the increase of proteinsolubility. Our results however indicatedthe ex-istence of other factors that modify the foamingbehaviour. Adebiyi and Aluko (2011) alreadyindicated the notable influence of pH on FC.Other factors such as the rapid unfolding at theair-water interface and limited intermolecularcohesion and flexibility of the protein could bealso responsible of FC changes (Chavan et al.,2001).

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III. Conclusions

Microfluidization at 100 MPa improved thetechno-functional properties of commercial PPIsamples. Protein solubility is clearly improvedwhat enhanced the thermal or acid gelationproperties and emulsifying capacity. Howeverthe effect of microfluidization depended on

sample characteristics influenced by the extrac-tion conditions of proteins, and on the envi-ronmental factors such as pH or ionic strength.Further studies about the effect of microflu-idization on the structure of protein aggregateswill allow understanding the role of proteinstructure on the resulting techno-functionalproperties of pea proteins.


This work was supported financially by European Funds for Regional Development (FEDER-FSEBourgogne 2014/2020), French Inter-Ministerial Unique Funds (FUI), and the Region of Burgundy(France) as part of project LEGUP Lot 3 2015 03 03.

References

[1] Adebiyi, Q.P., Aluko, R.E., 2011. Functional properties of protein fractions obtained fromcommercial yellow field pea (Pisum sativum L.) seed protein isolate. Food Chemistry, 128:902-908.

[2] Aluko, R.E., Mofolasayo, O.A., Watts, B.M., 2009. Emulsifying and foaming properties ofcommercial yellow pea (Pisum sativum L.) seed flours. Journal of Agricultural and FoodChemistry, 57: 9793-9800.

[3] Barac, M., Cabrilo, S., Pesic, M., Stanojevic, S., Zilic, S., Macej, O., Ristic, N., 2010. Profile andfunctional properties of seed proteins from six pea (Pisum sativum) genotypes. InternationalJournal of Molecular Sciences, 11: 4973-4990.

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[5] Crevieu, I., Carre, B., Chagneau, A.M., Quillin, l., Gueguen, J., Berot, S., 1997. Identificationof resistant pea (Pisum sativum L.) proteins in the digestive tract of chickens. Journal ofAgricultural and Food Chemistry, 45: 1295-1300.

[6] Chavan, U.D., McKenzie, D.B., Shahidi, F., 2001. Functional properties of protein isolates frombeach pea (Lathyrus maritimus L.). Food Chemistry, 74: 177-187.

[7] Davis, J., Sonesson, U., Baumgartner, D.U., Nemecek, T., 2010. Environmental impact offour meals zith different protein sources: case studies in Spain and Sweeden. Food ResearchInternational, 43: 1874-1884.

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[12] Krishina, T.G., Croy, R.R.D., Boulter, D., 1979. Heterogeneity in subunit composition of thelegumin of Pisum sativum. Phytochemistry, 18: 1879-1880.

[13] Laemmli, U.K., 1970. Cleavage of structural proteins during the assembly of the head ofbacteriophage T4. Nature, 227: 680-685.

[14] Laval, O.S., Adebowale, K.O., Ogunsanwo, B.M., Sosanwo, O.A., Bankole, S.A., 2005. On thefunctional properties of globulin and albumin protein fractions and flours of African locustbean (Parkia biglobossa). Food Chemistry, 92: 6816691.

[15] Mession, J.L., Chihi, M.L., Sok, N., Saurel, R., 2015. Effect of globular pea proteins fractionationon their heat-induced aggregation and acid cold-set gelation. Food Hydrocolloids, 46: 233-243.

[16] Mession, J.L., Sok, N., Assifaoui, A., Saurel, R., 2013. Thermal denaturation of pea globulins(Pisum sativum L.)âATmolecular interactions leading to heat-induced protein aggregation.Journal of Agricultural and Food Chemistry, 61: 1196-1204.

[17] Moure, A., Sineiro, J., Dominguew, H., Parajo, J.C., 2006. Funcionality of oilseed proteinproducts: A review. Food Research International, 39: 945-963.

[18] Munialo, C.D., Martin, A.H., van der Linden, E., de Jongh, H.H.J., 2014. Fibril formation frompea protein and subsequent gel gormation. Journal of Agricultural and Food Chemistry, 62:2418-2427.

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[19] Shand, P.J., Ya, H., Pietrasik, Z., Wanasundara, P.K.J.P.K., 2007. Physicochemical and texturalproperties of heat-induced pea protein isolate gels. Food Chemistry, 102: 1119-1130.

[20] Shen, L., Tang, C.H., 2012. Microfluidization as a potential technique to modify surfacepropertis of soy protein isolate. Food Research International, 48: 108-118.

[21] Sikorski, Z.E., 2001. Functional properties of proteins in food systems. In Z.E. Sikorski (Ed.)Chemical and functional properties of food proteins (pp. 113-135). Boca Raton/CRC Press.

[22] Sirtori, E., Resta, D., Arnoldi, A., Savelkoul, H.F.J., Wichers, H.J., 2011. Cross-reactivitybetween peanut and lupin proteins. Food Chemistry, 126: 902-910.

[23] Tzitzikas, E.N., Vincken, J.P., De Groot, J., Gruppen, H., Visser, R.G.F., 2006. Genetic variationin pea seed globulin composition. Journal of Agricultural and Food Chemistry, 54: 425-433.

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Evaluation of Quality and Shelf-life ofPasteurized Goat Milk Produced Under

Smallholder Condition in a Farmer Group

Yuni Suranindyah∗, F.Trisakti Haryadi, Diah Triwidayati

Faculty of Animal Science, Universitas Gadjah Mada, Yogyakarta, Indonesia

Abstract

The purpose of the study was to evaluate the quality and shelflife of pasteurizedgoat milk that was processed by smallholders in the farmer group. The studywas doneinthe district of Sleman,Yogyakarta,Indonesia. Materials consisted of20 samples of fresh milk collected from farmers before and after implementationof extension program and 10 samples of pasteurized milk.The pasteurization wasdone followed high temperature short time method using batch pasteurizer. Theproduct was packaged in plastic cup and stored in a refrigerator at a temperatureof 4 ◦C. Samples were analyzed to examine milk composition, alcohol and clot onboiling tests, to measure acidity, number of bacteria estimated with MBRT, freefatty acid and sensory evaluation focused on flavor. Shelflife of pasteurized milkwas determined on 0, 3, 5, 8 and 10 days of storage. The results showed freshmilk had total solid, fat and protein contents as 15.26%, 5.70% and 4.83%,respectively. Milk acidity was 0.23% and number of bacteria was around1500000 CFU/mL.Composition of pasteurized goat milk was not different tothat of fresh milk, while number of bacteria decreased into around 100000 to500000/mL.Milk showed negative result of alcohol and clot on boiling tests, theaverage of acidity and free fatty acid were 0.23%, and 0.87%, respectively. In 10days of storage free fatty acid levels began to rise to 0.99% and appeared rancidas a sign of milk damage and unaccepted for consumption. The conclusion waspasteurized goat milk that was processed in smallholder had good quality shownby high level of composition and normal in quality assessment. Shelf life of milkwas 8 days, based on high FFA content and appearance of rancid flavor.

Keywords: Quality, shelf life, pasteurized goat milk, smallholder, farmergroup


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In many region of Indonesia the consump-tion of goat’s milk began to increase in thelast few years because the milk was consid-

ered to provide essential nutrient and healthyfood. The nutritional benefit of goat milk wasindicated by high content of protein and fat,as around 4.09% and 6.6%, respectively (Cyril-laet al., 2015),rich in vitamin A, niacin, choline,inositol, easy to digest (Park, 2010), and goodsource of potassium, an essential mineral formaintaining normal blood pressure and heartfunction (Getaneh et al., 2016). Therefore theneed to maintain goat milk nutritional value.In Indonesia there was no standard quality forgoat milk, in certain case use standard of cowmilk.

The recent situation, availability of goatmilk for consumption is still low, because mostof milk was produced by small farm with fewnumber of goat ownership, low productionand quality and small capital (Utami, 2016).Thelimited production caused farmers had diffi-culties to sell milk individually to consumerbecause of inefficient marketing. To overcomethe problem there was need an effort, for exam-ple by developing milk processing collectivelyin the group and related to the purpose ofmaintaining the nutritional value of goat milkit was necessary to select the type of processingthat minimized the damage of nutrient content.Pasteurization is known as a rapid heating andsubsequent cooling of milk to kill off causedisease microorganisms. Pasteurization has al-lowed dairy farmers to distribute their milkto wider markets (Lewis, 2010).Therefore im-plementation of pasteurization would be ben-eficial to provide healthy food from goat milkwith high selling price.

Efficiency of pasteurization could beachieved if it processed large amount of milk,insmallholder situation can be obtained by col-lecting milk from farmers in the group.Tosupport pasteurization process, there wasneed good quality milk production, improvingknowledge and farmers kill, which could beachieved by conducting extension program, in-cluded counseling and training to the farmers.An example was showed by Delgado-Pertinez

et al. (2014)improving sanitary managementin the farm gave result to reduce milk bacte-ria.The extension program in this study wasprepared to support implementation of pas-teurization process, in order to achieve goodquality milk production and skill in process-ing. Goat milk pasteurization in this study wascarried out in a rural condition, therefore needto evaluate the result of processing.The studyaimed to evaluate the quality and shelf life ofpasteurized goat milk that was processed un-der smallholder condition. Result of the studywas expected to determine whether the prod-uct acceptable for consumption or not.


The study was conducted in a group of farmerswho produced goat milk, which located in thedistrict of Sleman, Yogyakarta, Indonesia. Datawere collected during the implementation ofextension program, focused to improve milk-ing hygiene and develop milk processing.Theprogram was held by delivered knowledgepertaining to standards milk quality, imple-mented hygienic milking practice and trainingto process milk by pasteurization.

MaterialsMaterial of study consisted of 20 samples ofEtawah Crossed bred goat milk, collected fromfarmers during the existing condition and af-ter implementation of extension program, 10samples of pasteurized milk as representedproduct of pasteurization during the trainingprogram. The study used equipment for milk-ing (bucket, towel and clean bottle to collectmilk directly from nipple, plastic container andfilter),sanitation (brush and shovel), pasteur-ization (small batch pasteurizer), packaging(plastic cup and electric cup sealer), storage(showcase refrigerator LG brand with mini-mum temperature of 2 ◦C) and ice cool boxto carry samples from farm to laboratory.Thestudy used small batch pasteurizer producedby a training center, Malang, East Java, Indone-sia. The capacity was 10 L, made of stainlesssteel completed with mixer and gas stove as

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heater. The cup sealer was a local product fromYogyakarta. The equipment was operated man-ually supported by electric power.The studyused laboratory equipment and chemicals toanalyze milk composition and quality.

MethodsRaw milk samples were collected during twoperiods, namely before and after extension pro-gram. Before extension program,reflected theexisting condition of farmer in the group. Sam-ple was taken from goats that were milkedby hand as it is practiced by farmers everyday. There was no cleaning preparation priorto milking and no special container to collectmilk(most farmer used plastic bottle). Afterextension, sample was taken from goats withgood milking process. The procedure includedof cleaning the pen, washed and dried udder,discarded first flow milk before collected milk.Farmers used hygienic container (clean bot-tle) to collect milk directly drained from theteat. This manner was done torestrict odorcontamination from environment. Milk wasimmediately filtered and stored in 4 ◦C usedrefrigerator.

Pasteurization was done in the room pre-pared for processing. The room has concretefloor and wall and supported with water andelectric source. The placelocated about 25 me-ters from goat pens. Pasteurization followedhigh temperature short time (HTST) method.Milk washeated until reached temperature of76 ◦C, kept for 30 seconds and subsequentlycooled in the same batch by flowing waterthrough outside part of milk container. Pas-teurized milk was packaged in the plastic cup,sealed and stored in refrigerator in 4oC. Ex-amination was conducted in the Laboratory ofAnimal Product Technology, Faculty of Ani-mal Science Universitas Gadjah Madato mea-sure milk composition (percentage of total sold,protein and fat), alcohol test, clot on boiling(COB) test, acidity, methylene blue reductiontest(MBRT) to estimate number of bacteria, freefatty acid (FFA), and sensory evaluation (milkflavor). Alcohol test in this study was done byadded 45% ethanolin the same volume of milk

sample then examined the coagulation (Kim etal., 2013). Total acidity content was measuredby titration 10 mL sample added with 3 to 4drops of phenolphthalein indicator with NaOH0.1N. Acidity was expressed as percentage oflactic acid (Meheret al., 2015).Clot on boilingwas examined by boiling 10 mL of milk sam-ple, in a test tube for 5 minutes in the a waterbath and observed coagulation in the milk sam-ple(Lai et al., 2016). Methylene blue reductiontest (MBRT)was done by added 1 mL of methy-lene blue indicator, into 10 mL in a test tubeand mixed properly.The tube was placed intowater bath at 37 ◦C. The change of colour wasobserved at different time interval (Meheret al.,2015). Jenitta and Mohan (2014) cited from sev-eral references explained that methylene BlueDye Reduction Test used enzymatic reductionof methylene blue by a metabolically active or-ganism turning the Methylene Blue colourless.Microbial was assessed by measuring dissolvedoxygen in milk sample and its reduction overtime to relate the rate of change in dissolvedoxygen levels with the population of bacteriain the sample. According to Standard NationalIndonesia (2000)there is corresponding of re-duction time and the number of bacteria inmilk. Reduction time as less than 2 hours, 2 to6 hours, 6 to 8 hours, and more than 8 hours,corresponded to 20 x 106, 4 to 20 x 106, 1 to 4x 106,and 500000 CFU/mL, respectively. Milkshelf life was examined after 0, 3, 5, 8 and10 days in storage. Sample was transportedusing ice cool box to the laboratory for analy-sis of nutrient content, alcohol test, COB test,MBRT, FFA content and sensory test (flavor).Milk flavor was examined by 8 panel to de-scribe whether milk has appeared rancid flavoror not. Data were statistically analyzed usingT-test, to compare means between raw and pas-teurized milk quality, Completely RandomizedDesign (CRD) to compare storage time with 10replication of each variable.


Quality of fresh goat milk from smallholderComposition and quality of fresh goat milk are

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presented in Table 1.The percentage of totalsolid (TS) and fat of milk sample after imple-mentation of extension program was higherthan those from the existing condition (P<0.05).The value of TS and fat content was at-tributable to the change of feeding practise,since during the extension program the goatswere given extra concentrates. The additional

concentrates was intended to increase goatmilk production but in fact also affected milkcomposition. Similarly reported by Soryalet al.(2004) that high level of concentrate in-creased fat, protein and total solids in milk ofgoats that were grazing on pasture. The re-sult did not show significant change of proteincontent.

Overall, the composition of goat milk in thisstudy were higher than that in several breedsof tropical goat showing the value of TS, fatand protein as 11.53 to 12.62%, 4.14 to 4.77%,and 2.54 to 3.52%, respectively (Lai et al., 2016;Zahraddeen et al., 2003). The composition wasalso higher than standard quality of premiumgoat milk of minimally 13.0%, 4.0% and 3.7%,respectively for TS, fat and protein (Thai Agri-cultural Standard, 2008). Malau-Aduli et al.,(2001) reported that yield and composition ofgoat milk were affected by breed, stage of lacta-tion, and plane of nutrition.Goat milk composi-tion in this study showed that milk of EtawahCrossed bred goat has specific characteristic,apart from the effect of feeding.

The negative result of alcohol and COB testsin milk samples both from the existing condi-tion and after extension program, indicatedthat milk was fresh and no lactose decompo-sition by bacteria in milk, so that milk aciditydid not increase and therefore no precipitation.Lai et al. (2016) explained that abnormal milkdeveloped precipitation due to the result ofdissociation of calcium caseinate salt. Basedon the result of alcohol and COB tests, goat

milk in this study was could stand the heattreatment and eligible to be processed. Alcoholtest was done by added 45% ethanol, followedGuoet al. (1998) explained that precipitationof fresh goat milk occurred with addition ofan equal volume of 44% ethanol. Low ethanolstability of goat milk may be related to the ratioof sodium to potassium, which is in goat milkwas much lower than cow’s milk (0.20 to 0.22versus 0.31).

Milk acidity in this study has the samevalue of 0.23 to 0.24% as reported by Nurliyaniet al. (2014) in Etawah Crossed bred goat milkand similar to acidity of cross dairy goat milkreported by Abdalla et al., (2007) with averageof 0.231%. There was a significant changedof the MBRT reduction time from 2.33 hoursto 5.25 hours in milk sample after extensionprogram. The result indicated an improvementin milk quality. Milk was classified into goodquality if the reduction time was 5 to 8 hour(Standard National Indonesia, 2000; Jenittaetal., 2014). According Muhammad et al., (2009)the reduction time of 2.33 hours equal to 1.5 x107CFU/mL, while 5.25 hours was the sameas 1.5 x 106 CFU/mL. Number of bacteria in

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raw goat milk after extension program wasabove maximum number required by Stan-dard National Indonesia for cow milk as 1.0x 106 CFU/mL (SNI, 2000) but less than thatin Etawah Crossed bred goat milk as 1.92 x106CFU/mL (Nurliyaniet al., 2014. Accordingto Hayes et al. (2001) standard plate countreflected the animal health status, sanitationefficiency, milking practices, and milk storagetemperature. Wanjekecheet al., (2016) showedno undesirable odour in goat milk which washandled under clean conditions. The resultsof laboratory examination, especially thoserelated to number of bacteria showed thatgoat milk quality in this study was affected byimprovement of sanitation in milking processand subsequently achieved good grade level.Based on the quality, milk could be sold asraw material or fresh milk,however, to supportincreasing farmer income, there is need to gethigher selling price by processing milk.

Quality, shelflife of pasteurized goat milkThe average of total solid, fat and protein con-tent of pasteurized milk were 14.70%, 5.50%and 4.83%, respectively (Table 2). There wasno significant change of major milk componentafter pasteurization process. Similarly Lund(1988)explained that pasteurization resulted alower nutrient content in foodstuff. Milk qual-ity as seen on Table 2, showed negative resultof alcohol and COB tests in all milk samples af-ter pasteurization and during storage.Alcoholtest useful to assess quickly the level of acidityand examine milk condition. The data showedthat pasteurized goat milk in this study wasnormal and stable until 10 days of storage.There was found no significant different in thereduction time of MBRT of milk during storage,the value ranged from 5.58 to 7.9 hours. Thosetime interval indicated that milk classified ingood grade, immediately after pasteurizationthe value even close 8 hours. The number ofbacteria in milk was less than 500000 CFU/mLfor reduction time of longer than 6 hours and15000 to 100000 CFU/mL for that in 8 hours orlonger (Muhammad et al., 2009).Based on theMBRT reduction time data (Table 2) there was

effect of pasteurisation on number of bacteriain milk. There reduction number was fromaround 4 x 106 CFU/mL in raw milk to around100000 to 500000 CFU/mL after process. Thedecline in the number of bacteria indicatedthat pasteurization effective to eliminate mi-croorganisms in goat milk. Anonymous (2014)explained that pasteurization destructs certaindisease-carrying germs and the prevention ofsouring milk. Number of bacteria in pasteur-ized goat milk in this study was higher than30000 CFU/mLas required by Standard Na-tional Indonesia (2000) but similar to the valueof 2.36 to 3.71 log CFU/mL or 370000 to 569400CFU/mL found in pasteurized goat milk asreported by Cupakova et al., (2012).During10 days storage, the MBRT reduction time in-dicated no significant change, therefore alsono different in number of bacteria. Accord-ing Beyene and Seifu (2000) microbial countsof raw and pasteurized goat milk started toincrease after 12 hours up to 96 hours under4 ◦C incubation. This study showed differentpattern of change in bacteria number, withslowly decreased during storage and in 10days it was estimated reached 4 to 20 x 106

CFU/mL.This amount was considered veryhigh number of bacteria in milk, therefore theshelf life should be determined in the periodbefore 10 days. In comparison with commonlypasteurized milk, shelf life of milk in this studywas shorter, since normally was around 2 to 3weeks (Spiegel, 2016). Low aseptic conditionof processing room has possibility to causecontamination and short storage time.

Free fatty acid (FFA) in pasteurized goatmilk increased significantly in 10 days of stor-age. At the same time milk started to ran-cid. According to Ecknes et al.(2006) the totalconcentration of free fatty acids is a measureof the degree of lipolysis in the milk, and ishighly correlated to the frequency of rancidand flavour. The FFA level(Table 2) was higherthan that reported by Nurliyani et al. (2014) infresh milk as 0.72% andSaputra (2015) 0.82%.High level of FFA could be affected by pro-cessing such as heating, mixing.According toPereira et al.(2007) the high shear stresses im-

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posed on milk during stirring, pumping andheat treatment may cause damage to the mem-brane that protects the milk fat globule fromthe action of lipases. Disruption of this mem-

brane facilitates the hydrolysis of triglycerides,which could lead to an excessive accumulationof FFA in milk.

Strzakowska et al., (2010) reported that un-der unfavourable conditions goat milk is sub-jected to lipolysis in which the FFA are pro-duced.This study considered shelf life of milkwas 8 days, because there was rising of FFAcontent and milk started to be rancid at 10 daysof storage.

III. Conclusion

Pasteurization process in smallholder condi-tion could produce good quality milk indicated

by high nutritional composition, normal valueof chemical assessment and number of bac-teria in milk and considered acceptable forconsumption. Shelf life of pasteurized goatmilk was determined to be 8 days based on theincreasing of FFA and appearance of rancidflavor. Implementation good milking practiceimproved the quality of raw milk which sub-sequently give benefit to provide material ofpasteurization.

References

[1] Abdalla, M.E.M,. and Zubeir, E.M., 2007. Effects of Different Management Practices on MilkHygiene of Goat Farms in Khartoum State of Suda. International Journal of Dairy Science (2):23-32.

[2] Anonymous, 2014. Raw Milk VS.Pasteurized Milk. A Campaign for real milk

[3] Beyene, F., Seifu, E., 2000. Variation in quality and fermentation properties of milk from localgoats. Agricultural Research and Extension Program. Langston University.

[4] Cyrilla, L., Purwanto, B.P., Atabany, A., Astuti, D.A., Sukmawati, A.,2015. Improving MilkQuality for Dairy Goat Farm Development. Media Peternakan 38(3): 204-211.

[5] Cupakova, S., Pospisilova, M., Karpiskova, R., Janstova, B., Vorlova, L., 2012. Microbiologicalquality and safety of goat’s milk from one farm. Acta Universitatis Agriculturae et SilviculturaeMendelianae Brunensis 44(6): 13-37.

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[6] Delgado-Pertifiez, M., Alcade, M.J., Guzman-Guerrero, J.L., Castel, J.M., Mena, Y., Caravaca, Y„2014. Effect of higiene-sanitary managementon goat milk quality in semi-extensive systems inSpain. Journal of Nutrition and Health Science 3: 2393-9060.

[7] Eknes, M., Kolstad, K., Volden, H., Hove, K., 2006. Changes in body reserves and milk qualitythroughout lactation in dairy goats. Small Ruminant Res. 63: 1-11.

[8] Getaneh, G., Mebrat, A., Wubie, A., Kendie, H., 2016. Review on Goat Milk Composition andIts Nutritive Value. J Nutr Health Sci 3(4): 401.

[9] Guo, M.R., Wang, S., Li, Z., Qu, J., Jin, L., Kindsted, P.S., 1998. Ethanol stability of goat’s milk.Int. Dairy J 8(1): 57-60.

[10] Hayes, M.C., Ralyea, R.D., Murphy, S.C., Carey, N.R., Scarlett, J.M, Boor, K.J., 2001. Identifica-tion and characterization of elevated microbial counts in bulk tank raw milk. J Dairy Sci. 84(1):292-8.

[11] Jenitta, M.B., Sherly, J., Mohan, K., 2014. Studies on Microbial Quantity and Dissolved OxygenContent of Raw Chilled Milk Samples Based On Methylene Blue Reduction Test and OxidationReduction Potential. International Journal of Engineering and Technical Research (IJETR) 2 (9):2321-0869.

[12] Kim, H.R., Jung, J.Y., Cho, I.Y., Yu, D.H., Shin, S.S., Son, C.H., Ok, K.S., Hur, T.Y,. Jung, Y.H.,Cho, iC.Y., Suh, G.H., 2013. Characteristics of dairy goat milk positive reaction of the alcoholprecipitation test in Korea. Korean J Vet Serv. 36(4): 255-261.

[13] Lai, C.Y., Fatimah, A.B., Mahyudin, N.A., Saari, N., Zaman, M., 2016. Physico-chemicaland microbiological qualities of locally produced raw goat milk. International Food ResearchJournal 23(2): 739-750.

[14] Lewis, P., 2010. Pasteurizing milk. Backwoods Home Magazine. May/June 123

[15] Lund, D., 1988. Effects of Heat Processing on Nutrients. in: Nutritional Evaluation of FoodProcessing, E. Karmas and R. S. Harris (Eds) (Online) pp. 319-354

[16] Malau-Aduli, B.S., Eduvie, L.O., Lakpini, C.A.M., Malau-Aduli, A.E.O., 2001. Effect ofsupplementation on the milk yield and composition of Red Sokoto does. Proc. of 26 thAnnualConference of Nigerian Society for Animal Production, p 353-356.

[17] Meher, R.K., Sethy, S., Nayak, N., 2015. Qualitative Analysis and Microbial Test of PasteurizedMilk. International Journal of Pharmacy and Biological Science 5(2): 215-219.

[18] Muhammad, K., Altaf, I., Hanif, A., Anjum, A.A., Tipu, M.Y., 2009. Monitoring hygienicstatus of raw milk marketed in Lahor city Pakistan. The Journal of Animal & Plant Sciences19(2): 74-77.

[19] Nurliyani, Suranindyah, Y., Pretiwi, P., 2014. Quality And Emulsion Stability Of Milk FromEttawah Crossed Bred Goat During Frozen Storage. Procedia Food Science 3:142-149

[20] Park, Y.W., 2010. Goat Milk Products: Quality, Composition, Processing, Marketing. In: W.G.Pond & N. Bell (Eds). Encyclopedia of Animal Science. 2nd Edition. Taylor and Francis. CRCPress. Boca Raton, FL

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[21] Pereira, R.N., Martis, R.C., Vicente, A., 2008. Goat milk free fatty acid characterization duringconventional and ohmic heating pasteurization. J. Dairy Sci. 91(8): 2925-37.

[22] Soryal, K.A., Zeng, S.S., Min, B.R., Hart, S.P., Beyene, F.A., 2004. Effect of feeding system oncomposition of goat milk and yield of Domiati cheese. Smal Ruminant Research 54: 121-129.

[23] Spiegel, A., 2016. Pasteurized vs. Homogenized milk: What’s the difference?

[24] Standard Nasional Indonesia, 1995. Susupasteurisasi’ Badan Standarisasi Nasional

[25] Strzalkowska, N., Jozwik, A., Bagnicka, E., Krzyzewski, J., Horbanczuk, K., Pyzel, B.,Sloniewska, D., Horbanczuk, J.O., 2010. The concentration of free fatty acids in goat milkas related to the stage of lactation, age and somatic cell count. Animal Science Papers andReports 28(4): 38-395.

[26] Thai Agricultural Standard 2008. Raw Goat Milk. National Bureau of Agricultural Communityand Food Standard Ministry of Agriculture and Cooperatives, Chatuchak, Bangkok p 2

[27] Utami, S.N., 2016. The Development of Ettawa Cross breeds at Turi Sub district, Sleman,Yogyakarta’ Agronomika 11:

[28] Wanjekeche, E., Macorosore, Z., Kiptanu, A., Lobeta, T., 2016. Quality and consumer ac-ceptability of goat milk with respect to goat breed and lactation stage. African Crop ScienceJournal 24: 95-99.

[29] Zahraddeen, D., Butswat, I.S.R., Mbap, S.T., 2007. Evaluation of some factors affecting milkcomposition of indigenous goats in Nigeria. Livestock Research for Rural Development 19:

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Mercury Level in Tissues of European Badger(Meles meles L.) from Eastern Slavonia, Croatia

Sinisa Ozimec1∗, Svjetlana Milin Radic2, Tihomir Florijancic1, Ivica Boskovic1,Andrea Gross-Boskovic3

1Josip Juraj Strossmayer University of Osijek, Faculty of Agriculture in Osijek,Vladimira Preloga 1, HR 31000 Osijek, Croatia D

2Ministry of Agriculture, Veterinary Inspection,Branch Office in Split, HR 21000 Split, Croatia

3Croatian Food Agency, ulica Ivana Gundulica 36b, HR 31000Osijek, Croatia

Abstract

Wild free-ranging mammals are important sentinels of environmental heavymetal pollution due to their permanent exposure in various habitats. The con-centrations of total mercury (Hg) was determined in samples of liver, kidneyand muscle of European badger, Meles meles L. (Carnivora, Mustelidae) fromeastern Slavonia region, north-eastern Croatia. Total of 29 badgers were col-lected at 20 localities by regular hunt or found killed in road traffic accidents, inthe period 2009-2011.Determination of mercury concentration was performedby atomic absorption spectrophotometry (AAS). Mean Hg concentration washigher in kidney (0.1833 mg kg−1) compared to liver (0.1401 mg kg−1) andmuscle (0.0381 mg kg−1). The highest concentrations were measured in adult,seven year old female (2.002 mg kg−1 in liver; 1.813 mg kg−1 in kidney;0.255 mg kg−1 in muscle). Higher mercury accumulation in kidney than liver,suggests an inorganic form of mercury which is excreted mainly by kidney.Assumed sources of heavy metals are geological ground, sediments and water inthe floodplain, dust emissions from the road traffic, improper waste disposal anduse of agricultural chemicals.

Keywords: Mercury, heavy metal, badger, pollution.

Anthropogenic activities can give rise tohigher environmental concentrations oftoxic elements, as the widespread con-

taminants of terrestrial and aquatic ecosystems.Heavy metals are very persistent in the envi-

ronment and by transferring through the foodchain can accumulate in various living organ-isms. Terrestrial vertebrates absorb mercuryvia food, water, air and through the skin (Bradl,2005). Organic mercury is strongly absorbed


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from the gastrointestinal tract and accumulatesin internal organs, mainly in the liver, kidneyand in the brain. Metallic and organic mer-cury are considered as neurotoxicants (Basu etal., 2005) while inorganic mercury is consid-ered as nephrotoxicant (Diamond and Zalups,1998). The presence of mercury is an indicationof environmental pollution from natural andanthropogenic sources such as industry, mu-nicipal waste incineration and agriculture. TheEuropean badger (Meles meles Linnaeus, 1758)is a member of the weasel family (Mustelidae)from the mammalian order Carnivora. Adultsmeasure up to 40 cm in shoulder height, 75-90cm in body length and 15-20 cm in tail length.Average body weight is 10 kg and it variesduring the year, reaching a peak just beforethe winter. Two black bands pass along thehead, starting from the upper lip and passingupwards to the whole base of the ears (Woods,2010). Badgers tend to live in areas with a mix-ture of agricultural habitats, deciduous wood-land or hedgerows, where they have access topermanent and plentiful food supply. The bad-gers are opportunistic omnivores, feeding onearthworms, insects, snails, small vertebratespecies, grasses, maize, cereals and soft fruits(Lanszki and Heltai, 2011). European badger iswidely distributed in Croatia, in the continen-tal part(Ozimec et al., 2014, 2015), and along

the Adriatic Coast,with exception of the upperAdriatic islands (Griffiths and Thomas, 1997).The aim of the study was to determine con-centration of mercury as toxic environmentalcontaminant in the muscle, liver and kidneyof European badger living in eastern Slavoniaregion (north-eastern Croatia).


Study areaSlavonia is a geographical region located in thenorth-eastern part of the Republic of Croatia,and on the southern rim of the Pannonian Plain.It is bordered by the Drava River in the north,the Sava River in the south and the DanubeRiver in the east (Figure 1). According to reliefcharacteristics, eastern Slavonia is mainly theflatland, consisting of the riverine floodplains,elevated loess plateaus and hills, with an alti-tudinal range from 78 m to 294 m.The climateis moderately warm.In the period 1993-2013,mean annual air temperature is 11.6 ◦C; min-imum in January (0.4 ◦C), maximum in July(22.3 ◦C). Absolute minimum temperature isâAS 25.1 ◦C, and absolute maximal tempera-ture is 40.3 ◦C. Annual precipitation is 703 mm;maximum in June (83 mm), minimum in Febru-ary (39 mm). Mean number of days with snowis 29 days.

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In the habitat composition, cultivated landis dominant with share of 62%, and includesagricultural fields with various crops, as wellas patchy distributed agricultural land withnatural vegetation, such as hedgerows andfield boundaries.Deciduous forests of willows(Salix spp.), poplars (Populus spp.), pedun-culate oak (Quercus robur) and common horn-beam (Carpinus betulus) make 26%. Grasslands(meadows and pastures) make 1.4%, whileinland freshwaters and wetlands make 4%.Constructed and industrial habitats (urbanizedareas, traffic infrastructure and industrial facil-ities) make 6.2% in the habitat composition.

Sampling and analysesSamples of muscle, liver and kidney were takenfrom 29 animals, legally hunted in the huntinggrounds or found killed in road traffic acci-dents in the period between 2009 and 2011.Location of 20 sampling sites is shown in Fig-ure 1. Upon collection, all samples were placedinto labelled plastic bags and stored at −20 ◦Cto avoid tissue degradation. All tissue sampleswere homogenized prior to laboratory analy-ses, done at Laboratory for Residue Controlof the Croatian Veterinary Institute in Zagreb

(Croatia).Sample tissues (2 g) were digestedwith 5 mL of HNO3 (65% v/v), 1 mL of H2O2(30% v/v) and 4 mL of H2O (Milli-Q grade)with a microwave closed system Multiwave3000 (Anton PaarMultiwave 3000).

Digested samples were diluted to a final vol-ume of 50 mL with Milli-Q H2O.Mercury wasanalysed using the cold vapour technique witha flow injection system coupled to an atomicabsorption spectrometer FIAS-100 equippedwith an autosampler. All specimens were runin batches that included blanks, a standard cal-ibration curve, two spiked specimens, and oneduplicate. All statistics were performed usingthe 8.0 Statistica Software Package (StatSoft,Inc., USA). Data were grouped according totissue and concentrations, given in wet weight,were expressed as arithmetic mean standarddeviation (SD), with minimum and maximumvalues.


The mercury concentrations determined inmuscle tissue, kidney and liver of Europeanbadger from the study area are presented inTable 1.

Mean Hg concentration in kidney washigher than those measured in liver and muscletissue. The highest Hg concentrations:2.002 mgkg−1 in liver; 1.813 mg kg−1 in kidney; 0.255mg kg−1 in muscle, were measured in adult,seven year old female.

Results obtained in the present study werecompared to those reported for European bad-ger in Gorski kotar area, located in mountain-ous, Dinaric region in western Croatia:0.084mg kg−1 in kidney; 0.037 mg kg−1 in liver

and 0.005 mg kg−1 in muscle (Bilandzic et al.,2012). Mean mercury concentrations in Eu-ropean badger from eastern Slavonia were 2times higher in kidney; 3.8 times higher in liverand 7.6 times higher in muscle than those mea-sured in animals from Gorski kotar. These tworegions of Croatia significantly differs in bio-geographical characteristics, anthropogenic im-pact and urbanization rate, as well as in habitatcomposition and distribution.

In Gorski kotar region forests make 80% of

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habitat types and the most widespread are Di-naric beech and fir forests and sub-alpine beechforests on limestone substrate. Mountain grass-lands make 15.5%, and cultivated land about1% (Ozimec et al., 2014). Oppositely, in easternSlavonia region, dominates cultivated agricul-tural land(62%), lowland forests make 26%;grasslands 1.4%, while urbanized areas, cities,villages, traffic infrastructure and industrialfacilities make 6.2% in the habitat composition.

In area of eastern Slavonia, the badgerprefers deciduous forests as the natural habi-tat. The forest soil and groundwater along thefloodplains can be contaminated by the loadof heavy metals from agricultural land and bythe pollution of watercourses. Another sourceof soil contamination which may cause harm-ful effect on living organisms is traffic-relatedheavy metals emissions. The number of roadvehicles in operation increased during the re-cent past, resulting in the emissions of heavymetals originating from brake, tire and roadwear, which are deposited with particles inroad dust.

High mercury concentrations in tissues of

badger may pose a threat for consumers ofvenison, particularly hunters and their fami-lies who consume game meat more often thanthe general populations. Nowadays, the bad-ger’s meat is very rarely consumed by peoplein Croatia.

III. Conclusions

Free-ranging population of European badger(Meles meles L.) in eastern Slavonia region maybe a suitable sentinel organism of environmen-tal heavy metal pollution due to its permanentexposure in various natural and semi-naturalhabitats, and specific role near the top of thefood chain in ecosystems. The bioaccumulationof mercury in the kidney of badger was higherthan those found in the liver and muscle tis-sue.Further studies are recommended and theyshould address the sources of contaminationand factors such as age, seasonal variations,food preferences and diet composition. Thestudy was supported by a grant from the Croa-tian Food Agency.

References

[1] Basu, N., Klenavic, K., Gamberg, M., O’Brien, M., Evans D., Scheuhammer, A.M., Chan, H.M.,2005. Effects of mercury on neuro chemical receptor-binding characteristics in wild mink.Environmental Toxicology and Chemistry, 24(6): 1444-1450.

[2] Bilandzic, N., Dezdek, D., Sedak, M., Dokic, M., Simic, B., Rudan, N., Brstilo, M., Lisicin,T., 2012. Trace elements in tissues of wild carnivores and omnivores in Croatia. Bulletin ofEnvironmental Contamination and Toxicology,88(1): 94-99.

[3] Bradl, H., 2005. Heavy Metals in the Environment: Origin, Interaction and Remediation.Elsevier/Academic Press

[4] Diamond, G.L., Zalups, R.K., 1998. Understanding renal toxicity of heavy metals. ToxicologicPathology, 26(1): 92-103.

[5] Griffiths, H., Thomas, D.H.,1997. The conservation and management of the European badger(Meles meles). Council of Europe Publishing.

[6] Lanszki, J., Heltai, M. 2011. Feed in habits of sympatric Mustelids in an agricultural area ofHungary. Acta Zoologica Academiae Scientiarum Hungaricae, 57: 291-304.

[7] Ozimec, S., Padavic, J., Florijancic, T., Boskovic, I., 2014. Monitoring of wild life habitatsin Dinaric karst region of Croatia. Journal of Environmental Protection and Ecology, 15(3):889-896.

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[8] Ozimec, S., Florijancic, T., Milin Radic, S., Bilandzic, N., Boskovic, I., 2015. Bio accumulation ofcadmium and lead in the European badger (Meles meles L.) from the Croatian Danube Region.Journal of Environmental Protection and Ecology, 16(2): 637-642.

[9] Woods, M., 2010. The Badger, 2nd edition, The Mammal Society.

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Removal of Tetracycline byCandida utilis-Polyacrylonitrile Biocomposites

Feray Kip∗, Unsal Acikel

Cumhuriyet University, Department of Chemical Engineering, Sivas, Turkey

Abstract

In this study, tetracycline adsorption by Candida utilis on immobilized poly-acrylonitrile (PAN) was investigated. The characterization of Candida utilison immobilized polyacrylonitrile (PAN) biocomposite and tetracycline adsorbedbiocomposite was performed by the FTIR and SEM analysis. To find the opti-mum operating parameter values, temperature was changed between 22 and55 ◦C, pH as 2-7, concentration as 10-100 mg/L. The maximum capacity ofPAN-Candida utilis biocomposite for tetracycline adsorption was obtained at pH4.0 and at 25 ◦C. Under these experimental conditions, the amount of adsorbedtetracycline per unit weight of adsorbent was determined to be 1.01 mg/g. Theadsorption equilibrium data were represented by the Freund lich isotherm modelwhile tetracycline kinetic data showed consistency with the pseudo-second-orderkinetic model. The adsorption enthalpy, entropy and Gibbs free energy changewere determined and the physicochemical nature of tetracycline adsorptionby PAN-Candida utiliswas observed to be exothermic and spontaneous. Theenthalpy, entropy and Gibbs free energy changes were found to be -14.79kj/mol,-1.54 j/mol, -10.14 kj/mol, respectively. This study proved that the novel PAN-Candida utilis biocomposite can be effectively used for tetracycline removal frombiomedical wastewaters.

Keywords: Wastewater, polyacrylonitrile (PAN), Candida utilis, tetracycline,adsorption

Blood lipid regulators known as drugresidues in wastewater are anti-inflammatories, antiepileptics, sedatives

and antibiotics (Drewes, 2007). Antibioticsare used to treat human, animal and plantdiseases (Martinez, 2009). Antibiotics whichare organic microcontaminants in wastew-ater unit processes are divided into seven

separate groups according to their biodegra-dation and physicochemical characteristics:(1) aminoglycosides, (2) amphenicols, (3) β-lactams, (4) macrolides, (5) antibiotic peptides,(6) polyethers or ionophores and (7) tetracy-clines (TCs). TCs are among the most usedones (Sarmah et al., 2006). TC is an amphotericmolecule (C22H24N2O8) and tricarbonyl-mid


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(C-1; C-2; C-3), phenolic diketone (C-10; C-11;C-12), dimethylamine (C-4) groups are multi-functional groups of binding carbon atomsthat can be ionized (Parolo et al., 2008). TCmay undergo protonation-deprotonation in theacidic environment as cationic (pH<3.3), hy-brid ionic (3.3<pH<7.68) and anionic (pH>7.68)in aqueous solutions (Zhao et al., 2013). Theadsorption method is also used for drug wastesin wastewater in addition to biodegradationand chemical degradation. Caroni et al. (2009),Brigante et al. (2011), Godos et al. (2012) usedthe adsorption method to remove TC withchitosan particles, composite materials con-taining titanium-silica, and adsorbents such asalgae, respectively. Cells can be immobilizedon natural or synthetic supports with the im-mobilization method (Mattiason, 1983). Hunget al. (2011) found out in the study they car-ried out that immobilized cellulose displayeda higher hydraulic activity with the immobi-lization of cellulose to electrospun polyacry-lonitrile (PAN). In this study, the adsorptionof TC with biocomposite materials preparedwith PAN and Candida utilis was examined.Itwas proved as a result of the SEM and FTIRanalysis that the biocomposite created withPAN-Candida utilis with the immobilizationmethod was higher than PAN in the removalof TC.


ReagentsThe chemicals used in the experiments areof Sigma-Aldrich brand, and Candida utilisATCC 9950 ferment strains obtained fromAnkara University, Department of Biology.TC hydrochloride was purchased from Merck(Darmstadt, Germany) and 1000 mg/L of TCstock solution prepared was diluted into 10-100 mg/L concentrations.

Immobilisation of Candida utilis on PAN1 g of PAN was added to 1 g of dryCandida utilis microorganism and they weremixed. After keeping the mixture at roomtemperature for 12 hours, batch system experi-

ments were performed.

Batch Reactor ExperimentsThe adsorbents used in the experiment arethe biocomposite material formed with PANand immobilization of Candida utilis on PAN.The optimum reproduction conditions ofCandida utilis were determined to be 25 ◦Cand pH 4. Candida utilis was left for repro-duction at 95 rpm mixing speed for 4 days.Candida utilis obtained afterwards was cen-trifuged and stored in the fridge. Experimentalstudies were examined in the batch system. Af-terwards, a specific amount was taken fromthe samples and centrifuged and the adsorp-tion values were measured by using the UVspectrometer at 460 nm. The adsorption of theTC solutions prepared in 10-100 mg/L concen-tration was examined for 10-240 minutes. Themaximum adsorption effect of the TC solutionin 100 mg/L concentration between 25 − 50 ◦Cwas measured to determine thermodynamicparameters and the adsorption amount wascalculated (Equation 1).

(1)

Where is the adsorption of TC solutionsbiocomposite, C0 ve Ce is the initial and equilib-rium concentration (mg/L), qe is the amountof the substance adsorbed on the unit adsor-bent (mg/g), v is the solution volume (L) ve mis the amount of biocomposite (g).

Adsorption IsothermsMathematical adsorption isotherms which de-fine the TC ion dispersion between the liquidand solid phase in adsorption processes canbe explained bythe Langmuir isotherm model(Equation 2) and Freundlich isotherm model(Equation 3)

(2)

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(3)

Where qe is the amount of TCadsorbed atequilibrium(mg/g), Qmax is the maximumadsorption capacity of the adsorbent (mg/g),KL is the Langmuir consttant related to affinityof TC to the adsorbent (L/mg), KFis the Fre-undlich constant [(mg/g) (L/mgl/n)] relatedto the bonding energy, Ce is the equilibriumconcentration of TC in the solution (mg/L), nis the adsorption degree(Cheung et al., 2003).

Adsorption KineticsThe equations used to determine adsorptionkinetics are as follows. The pseudo-first-orderkinetic model:

(4)

The pseudo-second-order kinetic model isexpressed as follows and given with the follow-ing formula:

(5)

Where qe is the equilibrium adsorptioncapacity (mg/g), qt is the certain t time in-stant adsorption capacity (mg/g), k1 is thefirst-order rate constant (dk−1), k2 is the econd-order rate constant (g/mgdk) (Bayat, 2002).

Adsorption ThermodynamicsThe thermodynamic parameters of enthalpy,entropy and free energy change for the adsorp-tion process are given in Equation 6 (Khesamiand Capart, 2005).

(6)

Where ∆G0 is the free energy change(kJ/mol), ∆H0 is the enthalpy change (kJ/mol),∆S0 is the Entropy change (kJ/mol K), T is theabsolute temperature (Kelvin).


Adsorption KineticThe contact time for TC adsorption was exam-ined in the stationary initial TC concentrationfor PAN and PAN-Candida utilis biocomposite.When Log (qe-qt) versus t is displayed in agraph, figure 1-a line is obtained; and whent/qt versus t is displayed in a graph, figure1-b line is obtained. Although TC adsorptionwas rapid at the beginning, it decelerated overtime.

When the experimental qe and correlationvalues were examined (Table 1), it was ob-served that PAN-Candida utilis biocompositewas consistent with the pseudo-second-orderkinetic model. The constants for the adsorp-tion kinetic model are presented in Table 1 for100 mg/L TC concentration.

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Adsorption IsothermsR2 values determine the isotherm type andif R2>1, it signifies that it is unfavorable foradsorption, if 0<R2<1, it signifies that the con-dition of favorability for adsorption has beenensured. When the adsorption isotherms wereexamined, it was observed that PAN and PAN-Candida utilis biocomposite is consistent with

the Freundlich isotherm for TC (Figure 2-a).This condition indicates that the energy isdispersed on the biocomposite surface het-erogeneously and that an interaction existsbetween specific regions and TC functionalgroups (Chang et al., 2009). PAN-Candida utilisbiocomposite showed a higher removal for TConly in comparison with PAN (Table 2).

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pH value in aqueous solutions plays an im-portant role in adsorption processes. When thepH range of experimental studies is examined,it is observed that as pH increases the removalof TC ions decreases in the range between 3.85and 4.3 as in figure 3 because while H+ ion

in the medium causes the increase in concen-tration, the adsorbent surface gains (+) chargewith the adsorption of H+ ions. Thus, electro-static interaction between TC ions begins todecrease (Chen and Huang, 2010).

Thermodynamic ParametersThe change of the Gibbs free energy, enthalpyand entropy equilibrium constant with tem-perature was calculated with the ∆G versus Tgraph as seen in figure 4. The negative ∆Gvalues indicate that TC was adsorbed by PANand PAN-Candida utilis biocomposite sponta-

neously. The negative ∆S value ensured themore regular transition of liquid moleculesbetween solid and liquid on the solid phasesurface during adsorption. The negative ∆Hvalue (Table 3) in this spontaneous event dueto the equilibrium condition showed that theinteraction on the surface was exothermic.

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FTIR and SEM AnalysesThe chemical functional vibration character-istics of PAN on the groups display theFTIR spectrum for pre-adsorption and post-

adsorption in figure 5-a and figure 5-b. Thepeaks which show the bonds of CH2, C≡N,C=O, C-O and C-H are present in the FTIRspectrum of PAN.

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If the adsorption peak is in the range of3153-3216 cm−1, the presence of C-H bonds inCH, CH2 and CH3 molecules has also been ob-served (Feldmann, 2010). Another peak showsnitryl groups (C≡N) in polyacrylonitrile chainin the range of 2148-2176 cm−1. The peaks inthe range of 1118-1272 cm−1 are due to thebond between C-O, the peaks in the range of1561-1532 cm−1 and 1684-1668 cm−1 originatefrom the vibrations observed in different situa-tions.

After adsorption, the peak severity of PANis observed to decrease. This situation indi-cates that the bonds are weakened and thatsome replacements occur between the bonds.It is considered that before adsorption (fig-ure 5-b) for Candida utilis-PAN biocomposite,3546 cm−1 peak originates from hydroxyl (-OH) bond, 2715.99 cm−1 peak originates fromthe C-O bond in carboxyl groups, 2115.99cm−1 and 1133.41 cm−1 peaks originate fromprimary and secondary amines and amides(Coleman and Petcavich, 1978). When the

FTIR spectrum is examined, it is seen that thepeak severity observed after adsorption forPAN (figure 5-a) and for Candida utilis-PANbiocomposite (Figure 5-b) has increased com-pared to pre-adsorption and produced higherpeaks. This situation has originated from theinteraction of the multi-functional group withTC ions due to adsorption process.

Thermodynamic ParametersSEM images are presented in figure 6 inorder to examine the pre-adsorption andpost-adsorption morphological characteristicsofCandida utilis-PAN biocomposites. As under-stood from the experimental results, the TCadsorption values for Candida utilis-PAN bio-composite turned out to be higher. It wasobserved that due to the porous structureof Candida utilis-PAN biocomposite before ad-sorption, the surface area which increased withthe pore size after adsorption was completelyfilled with TC ions (Ahmad et al., 2003).

III. Conclusion

In this study, TC adsorption was examinedwith the biocomposite material prepared withPAN and Candida utilis. The adsorption skills

of Candida utilis on their own increased the ad-sorption capacity of a newly-developed bio-composite material. The experimental datawere observed to be compatible with the Fre-

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undlich isotherm model in different concen-trations. Kinetic parameters were calculatedby using the pseudo-first and second-order ki-netic models under optimum conditions. TheTC removal was higher only in comparisonto PAN for PAN-Candida utilis biocomposite.The Gibbs free energy, enthalpy and entropyequilibrium constant were calculated accord-

ing to the temperature change for thermody-namic parameters. The negative ∆G valuesshowed that TC was spontaneously adsorpedby PAN and PAN-Candida utilis biocomposite.With this study carried out, it is considered thatnew biocomposite materials will become an al-ternative for the removal of drugs containingTC in wastewater.

References

[1] Ahmad, M.F., Haydar, S., Quraishi, T. A., 2003. Enhancement of biosorption of zinc ionsfrom aqueous solution by immobilized Candida utilis and Candida tropicalis cells. InternationalBiodeterioration & Biodegradation, 83: 119-128.

[2] Bayat, B., 2002. Comparative study of adsorption properties of Turkish fly ashes, The case ofnickel(II), copper(II) and zinc(II). J. Hazard. Mater., 95(3): 251-273.

[3] Brigante, M., Schulz, P.C., 2011. Remotion of the antibiotic tetracycline by titania and titania-silica composed materials. J. Hazard. Mater., 192: 1597-1608.

[4] Caroni, A.L.P.F., Lima, C.R.M.. Pereira, M.R., Fonseca, J.L.C., 2009. The kinetics of adsorptionof tetracycline on chitosan particles. J. Colloid Interface Sci. 340: 182-191.

[5] Chang, P., Li, Z., Yu, T., Munkhbayer, S., Kuo, T., Hung, Y.., Jean, Lin, J. K., 2009. Sorptiveremoval of tetracycline from water by palygorskite. J. Hazard. Mater., 148.

[6] Chen, W.R., Huang, C.H., 2010. Adsorption and transformation of tetracycline antibiotics withaluminum oxide. Chemosphere, 79: 779-785.

[7] Cheung, W.H., Ng. J.C.Y., McKay. G., 2003. Equilibrium studies for the sorption of lead fromeffluentsusing chitosan. Chemosphere, 1021-1030.

[8] Coleman, M.M., Petcavich, R.J., 1978. Fourier transform infrared studies on the thermaldegration of polyacrylonitrile. J. of Polymer Science, 821-832.

[9] Drewes, J.E., 2007. Removal of pharmaceutical residues during wastewater treatment, in: M.Petrovic, D. Barcelo (Eds.), Analysis, Fate and Removal of Pharmaceuticals in the Water Cycle,vol. 50, Wilson & Wilson’s, Elsevier, Amsterdam, pp. 427-447.

[10] Feldmann, H., 2010. Horst Yeast, Molecular and Cell Bio, Wiley-Blackwell, Germany.

[11] Godos, I., Munoz, R., Guieysse, B., 2012. Tetracycline removal during wastewater treatmentin high-rate algal ponds. J. Hazard. Mater., 229-230, 446-449

[12] Hung, T.C., Fu, C.C., Su, C.H., 2011. Immobilization of cellulase onto electrospun polyacry-lonitrile (PAN) nanofibrous membranes and its application to the reducing sugar productionfrom microalgae. Enzyme and Microbial Technology, 30-37.

[13] Khesami, L., Capart, R., 2005. Removal of Chromium (VI) from aqueous solutions by activatedcarbons: kinetic and equilibrium studies. J. Hazard. Mater., 123: 223.

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[14] Martinez, J.L., 2009. Environmental pollution by antibiotics and by antibiotic resistancedeterminants. Environ. Pollut., 2893-2902.

[15] Mattiason, B., 1983. In immobilized cells and cellular organelles Vol. I & II. Bo Mattiason(Ed.), CRC Press Inc.

[16] Parolo, M.E., Savini, M.C., Valles, J.M., Baschini, M.T., Avena, M.J., 2008. Tetracycline adsorp-tion on montmorillonite:pH and ionic strength effects. Appl. ClaySci., 179-186.

[17] Sarmah, A.K., Meyer, M.T., Boxall, A.B.A., 2006. A global perspective on the use, sales, expo-sure pathways, occurrence, fate and effects of veterinary antibiotics (VAs) in the environment.Chemosphere., 725-759

[18] Zhao, Y. Tan, Y. Guo, Y. Gu, X, Wang, X., Y. Zhang, Y., 2013. Interactions of tetracycline withCd(II), Cu (II) and Pb (II) and their cosorption behavior in soils. Environ. Pollut., 206-213.

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Investigation of Acid Orange 74 DyeAdsorption with Anaerob Activated Sludge

Gamze Topal Canbaz1∗, Unsal Acikel 1, Yesim Sag Acikel 2

1Cumhuriyet University, Engineering Faculty,Department of Chemical Engineering, 58140 Sivas, Turkey

2Department of Chemical Engineering, Faculty of Engineering,Hacettepe University, 06800, Beytepe, Ankara, Turkey

Abstract

In this study, anaerob activated sludge obtained from Sivas Wastewater Treat-ment Plant was used for the removal of Acid Orange 74 (AO74) dye. Theadsorptive properties of the anaerob activated sludge were tested as a functionof pH (2-5), contact time (10-240 min) and initial dye concentrations (25-750mg/L). Maximum adsorption of AO74 by activated sludge was obtained at pH4 and optimum contact time was determined as 240 minute. It was observedthat the amount of adsorbed AO74 per unit weight of adsorbent increased withthe increase of AO74 dye concentration. The data were fitted to the Langmuirand Freundlich isotherm models. With respect to the Langmuir model, when thesurface of the activated sludge was saturated with AO74 as a complete layer, themaximum adsorbed amount of AO74 per unit weight of activated sludge, Q,was142.85 mg/g and adsorption energy constant K was 0.0036 mg/L. Freundlichconstant KF showing adsorption capacity was determined as 0.706 L/g, theadsorption intensity parameter indicating favourable adsorption, n, was 1.063.According to the results obtained; activated sludge can be used as an adsorbentfor AO74 removal effectively from waste-water.

Keywords: Wastewater, acid orange 74 (AO74) dye, adsorption, activatedsludge

Dyes are a kind of organic compoundswhich are highly visible and can becarcinogens and toxic to aquatic life in

water. They have been widely used in differ-ent industries, such as textile, leather, paper,and plastics (Li et al, 2011). Most of the syn-thetic dyes and their degradation products are

of great environmental concern due to theirwidespread usage, toxic and carcinogenic andtheir low removal rate during aerobic wastew-ater treatment (Robinson et al., 2001; Khan etal., 2015; Gupta et al., 2015). The discharge ofcoloured wastes into receiving streams causesserious environmental problems such as affect-


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ing photosynthetic activity in aquatic life dueto reduced light penetration because of per-sistent and recalcitrant nature of various dyes.The dyes in waterways can be detected easilyeven though in small concentrations. Thereare more than 100,000 commercially availabledyes with 7 x 105 tons of dyestuff productionannually (Tunc et al., 2009). Due to their chem-ical structure, the paints are resistant to fadingwhen exposed to light and chemicals. Decol-orize of the dyes is quite difficult because of thecomplex molecular structures (Robinson et al.,2002, Mishra and Tripathy, 1993). Many meth-ods such as ion exchange, membrane technol-ogy, oxidation or ozonation, coagulation andadsorption are employed to remove dyes fromindustrial effluents (Chinwetkitvanich et al.,2000, Petzold et al., 2007). Adsorption systemwhich is a one of the methods and it has rapidlyattracted attention due to the high quality ef-fluents with low concentration of dyes (Walkerand Weatherley, 1998). Activated sludge is themost effective and commonly used adsorbentfor the treatment of dye wastewater (Liu etal., 2010) and it is a well-known biomass usedfor the purification of some industrial effluentsand domestic wastes. Probably the most abun-dant source of mixed microbial biomass is theactivated sludge wastewater treatment process(Aksu and Akin, 2010).

In this study, the activity of activated sludgewas investigated as a function of pH, contacttime and initial dye concentration. The acti-vated sludge is preferred because of its lowcost, easy and abundant availability. Accord-ing to the literature, it has been determinedthat activated sludge is used for the adsorptionof many dye species, but no adsorption stud-ies have been found with AO74 dye. In thisstudy, optimum conditions for the activatedsludge and AO74 adsorption process were de-termined.


The activated sludge used in the experimentalstudies was obtained from the Sivas Wastew-ater Treatment Plant It was performed three

processes such as washing, drying and milling.First, the activated sludge was washed withdistilled water several times in order to elim-inating the impurities. Second, the activatedsludge was dried at 60 ◦C until all the waterwas removed. Third, the fully-dried activatedsludge was milled and maintained at 60 ◦C foruse in experiments.

The stock solution of AO74 (C16H11CrN5NaO8S;MW = 508.34 g/mol, λ max = 455 nm,Sigma-Aldrich) was prepared 1 L at 1000 mg/ L by taking the required amount of AO74dye (1 g). Different AO74 dye concentrationswere obtained from the stock dye solution bymaking the necessary dilutions. Batch sorp-tion experiments were carried out understandsthe effects of solution pH, contact time, andinitial dye concentrations. Experiments weredone in Erlenmeyer flasks with 100 mL dyesolution in temperature-controlled shakers at200 rpm. The experiments were performedunder variable solution pH (2, 3, 4, and 5), ini-tial dye concentration (25-750 mg/L), contacttime (10-240 min). Solution pH was adjustedwith HCl or NaOH. After reaching equilibrium,the adsorbent was separated with a centrifugeand the concentration of AO74 in supernatantliquid was measured by a spectrophotometer(Shimadzu UV-1201 V) to be λ max 455 nm. Theadsorption isotherm was determined for themono sorption experiments. The average val-ues of experimental measurement results wereused in the calculations. The amount of dyesadsorbed (qe; mg/g) and the percent dye ad-sorption (%) were determined by Eqs. (1) and(2), respectively;

(1)

(2)

Where Co and Ce are the initial and finaldye concentration (mg/L), V is the volume ofthe dye solution (L) and m is the mass of ad-sorbent (g).

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Effect of solution pHIt was reported that the solution pH playedan important role on adsorption (Zhang et al.,2011). Therefore; the effect of different solu-tion pH on AO74 adsorption with the anaerobactivated sludge was investigated. For this pur-pose, the pH of the AO74 solution is adjusted

to be 2-5. At room temperature, 5 g / L anaerobactivated sludge concentration was constant.The results obtained are presented in Fig. 1.The amount of adsorbed AO74 increased up topH 4 and the maximum adsorption of AO74was observed at pH 4 as 64%. However, a de-crease was observed in the amount adsorbedAO74 at pH 5. According to this results, pH 4was chosen as the optimum adsorption value.

Contact time experimentsThe contact time experiments were carried outfor 10-1440 minutes in order to investigatethe effect of contact time on the adsorptionof AO74 dye on anaerob activated sludge andto determine the maximum adsorption time

of adsorption capacity. It was observed thatthe amount of adsorbed dye reached to theequilibrium after 240 minutes. For this reason,optimum contact time for AO74 dye adsorp-tion was chosen as 240 min (Figure 2).

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Effect of initial dye concentrationThe effect of initial dye concentrations from 25to 750 mg/L are presented in Fig. 3. It canbe seen that an increase in the initial dye con-centration causes an increase in the amountof AO74 adsorbed dye. According to initial

dye concentrations 25mg/L and 750 mg/L, theamount of adsorbed AO74 was 2.58 mg/g and107.76 mg/g respectively. T The amount ofadsorbed dye increases because of retardationof resistance of dye uptake (Mittal et al., 2010)

Adsorption isothermsThe Langmuir model was used to evaluatemaximum adsorption capacity on a mono-layer in which all adsorption sites are identicaland energetically equivalent (Khan et al., 2015;Kaur et al., 2014). The Langmuir equation inthe non-linear form can be expressed as follows(Eq. 3) (Khan et al., 2015):

(3)

where qe and Qo are the amount of equilib-rium adsorption capacity and the maximum

adsorption capacity (mg/g), respectively; Ce isthe equilibrium solution concentration (mg/L);b is the Langmuir constant (L/mg).

In contrast, the Freundlich isotherm as-sumes a heterogeneous surface with a non-uniform distribution for heat adsorption overthe surface (Ozcan et al., 2009). The isothermparameters were calculated using the non-linear form of the Freundlich equation (Eq. 4):

(4)

Where kF is the Freundlich adsorption con-stant (L/g), n is the empirical parameter.

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In this study, the correlation coefficients (R2)obtained in both isotherms were close to eachother and the study is compatible with bothisotherms (Table 1).

III. Conclusions

In this study, the anaerobic activated sludge ob-tained from wastewater treatment plants wasused as an adsorbent in AO74 dye removal.Adsorption was analyzed at different condi-

tions of pH, contact time and initial dye con-centrations. Maximum adsorption of AO74by activated sludge was obtained at pH 4 andoptimum contact time was determined as 240minute. It was observed that the amount ofadsorbed AO74 per unit weight of adsorbentincreased with the increase of AO74 dye con-centration. The Langmuir adsorption capaci-ties for AO74 dye was 142.85 mg/g. The re-sults show that the cheap and abundant activesludge is an effective adsorbent for AO74 re-moval.

References

[1] Aksu, Z., Akin, A.B., 2010. Comparison of Remazol Black B biosorptive properties of live andtreated activated sludge. Chemical Engineering Journal 165: 184-193.

[2] Chinwetkitvanich, S., Tuntoolvest, M., Panswad, T., 2000. Anaerobic decolorization of reactivedye bath effluents by a two-stage UASB system with tapioca as a cosubstrate. Water Res. 34:222-232.

[3] Gupta, V.K., Khamparia, S., Tyagi, I., Jaspal, D., Malviya, A., 2015. Decolorization of mixtureof dyes: a critical review. Global J.Environ. Sci. Manage. 1(1): 71-94.

[4] Kaur, S., Rani, S., Mahaj, R.K., Asif, M., Gupt, V.K., 2014. Synthesis and adsorption prop-erties of mesoporous material for the removal of dye safran in: kinetics, equilibrium, andthermodynamics. J. Ind. Eng. Chem. 22: 19-27.

[5] Khan, T.A., Khan, E.A., Shahjahan, 2015. Removal of basic dyes from aqueous solution byadsorption onto binaryiron-manganese oxide coated kaolinite: non-linear isotherm and kineticsmodeling. Appl. Clay Sci. 107: 70-77.

[6] Liu, F., Teng, S., Song, R., Wang, S., 2010. Adsorption of methylene blue on anaerobic granularsludge: Effect of functional groups. Desalination 263: 11-17.

[7] Mishra, G., Tripathy, M.A., 1993. A critical review of the treatment for decolourization of textileeffluent. Colourage 40: 35-38.

[8] Mittal, A., Mittal, J., Malviya, A., Kaur, D., Gupta, V.K., 2010. Decoloration treatment ofa hazardous triarylmethane dye,Light Green SF (Yellowish) by waste material adsorbents.J.Colloid Interface Sci. 342: 518-527.

[9] Ozcan, A.S., Gok, O., Ozcan, A., 2009. Adsorption of lead(II) ionsonto 8-hydroxy quinolineimmobilized bentonite. J. Hazard.Mater. 161: 499-509.

[10] Petzold, G., Schwarz, S., Mende, M., Jaeger, W., 2007. Dye flocculation using polyampholytesand polyelectrolyte-surfactant nanoparticles. J. Appl. Polym. Sci. 104: 1342-1349.

[11] Robinson, T., Chandran, B., Nigam, P., 2002. Removal of dyes from an artificial textile dyeeffluent by two agricultural waste residues, corncob and barley husk, Environ. Int. 28: 29-33.

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[12] Robinson, T., McMullan, G., Marchant, R., Nigam, P., 2001. Remediation of dyes in textileeffluent: a critical review oncurrent treatment technologies with a proposed alternativeBioresour. Technol. 77: 247-255.

[13] Tunc, O, Tanaci, H, Aksu, Z., 2009. Potential use of cotton plant wastes for the removal ofRemazol Black B reactive dye. Journal of Hazardous Materials 163: 187-198

[14] Walker, G.M., Weatherley, L.R., 1998. Fixed bed adsorption of acid dyes onto activated carbon.Environ. Pollut. 99: 133-136.

[15] Li, W.H., Yue, Q.Y., Gao, B.Y., Ma, Z. H., Li, Y.J., Zhao, H.X., 2011. Preparation and utilizationof sludge-based activated carbon for the adsorption of dyes from aqueous solutions. ChemicalEngineering Journal 171: 320-327.

[16] Zhang, D., Niu, H., Zhang, X., Meng, Z., Cai, Y., 2011. Strong adsorption of chlorotetracylineon magnetite nanoparticles. J.Hazard. Mater. 192: 1088-1093.

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Impact of Pulsed Electric Fields and HeatTreatment on Quality of Licorice Drink: A

Comparative Study

Sibel Uzuner, Gulsun Akdemir Evrendilek∗

Department of Food Engineering Faculty of Engineering and Architecture,Abant Izzet Baysal University Bolu Turkey

Abstract

Licorice (Glycyrrhiza glabra) drink (sherbet) is one of the most consumed tradi-tional drinks especially in south and south eastern cities in Turkey. However, ithas very short shelf-life due to spoilage by the yeast and bacteria. Processing oflicorice drink by PEF (upto 30 kV/cm electric field strength for 148 µs treatmenttime), heat (upto 90 ◦C for 3 min) and combination of mild heat+PEF (40 ◦Cfor 3 min + 23 kV/cm electric field strength) processing with measurement ofphysical and sensory properties as well as microbial inactivation revealed thatPEF processing was superior to heat for the preservation of most of the impor-tant properties with reasonable amount of microbial inactivation. However,combination of mild heat+ PEF processing also provided significant amount ofmicrobial inactivation without adversely affecting important properties of thedrink. It is suggested that either PEF or mild heat + PEF can be used to processlicorice drink.

Keywords: Pulsed electric fields (PEF), licorice drink, microbial inactivation,sensory properties

Traditional drinks -in most of thecountries- have an important place forcenturies, but due to their low produc-

tion volume and short shelf-life, they areprone to diminish because they are not pro-cessed by proper processing technologies thatdo not cause changes in physical and sen-sory properties. Licorice drink (sherbet) pre-pared by the immersion of the dried licorice(Glycyrrhiza glabra) in the form of hairy rootsfor couple hours at room temperature, removal

of roots from liquid part and cooling it downfor couple hours is one of the most consumedtraditional drinks especially in south and southeastern cities in Turkey. The main sweet com-pounds called glisirizin fifty times sweeter thanthe normal sugar is the main distinct com-pound in licorice drink. However, it has veryshort shelf-life due to the spoilage by yeastand bacteria (Al-Balawnih et al., 2017). Cur-rent efforts made to extend shelf-life of licoricedrink by heat processing resulted in deteriora-


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tion of physical and sensory properties; thusalternative technologies are in search to pro-cess licorice drink with preservation of physicalproperties as well as its bioactivity.

Pulsed electric field (PEF) processing in-volving 20-80 kV/cm electric field strengthapplication in a matter of microseconds havegained increasing attention in the food indus-try (Sampedro et al., 2014) due to the supe-rior benefits over most of the processing tech-nologies for the inactivation of microorganismsand enzymes (Agcam et al., 2016; Zhao et al.,2012), preservation of colour, flavor (Barba etal., 2012), aroma compounds and nutritionalproperties (Evrendilek et al., 2016) of fruits andvegetables juices.

Although different juices were processedsuccessfully by PEF, studies related to process-ing of traditional drink are limited.

Therefore, processing of licorice drink byPEF, heat and mild heat+PEF with the mea-surement of physical and sensory propertiesin addition to inactivation of both natural mi-croflora and inoculated foodborne pathogensare in search in this study.


Licorice drink preparationLicorice roots fringes of 30 g was immersedin five L of drinkable water and waited for 12h at refrigeration temperature. After removalof the roots by sieving, the drink was kept inrefrigeration until use.

Test microorganismsEscherichia coli O157:H7 (EDL 931 04054) cul-ture was obtained from Refik Saydam Hifzissi-hha Research Center Culture Collection Labo-ratory (Ankara, Turkey) and Salmonella Enteri-tidis (OSU 799) culture was obtained from theculture collection of Department of Microbiol-ogy of the Ohio State University (Columbus,OH).

Activation and inoculation of the culturesinto licorice drink was performed according toprocedure explained by Evrendilek (2017).

PEF processing unitA laboratory-scale PEF OSU-4A systemequipped with six co-field flow treatmentchambers in 0.23 cm chamber diameter and0.292 cm gap distance that provide squarewave bipolar pulses, a trigger generator (Model9310 Pulse Generator, Quantum Composer Inc.,Bozeman, MT, USA), an oscilloscope (Model9310 TDS-320, Tektronix Inc., Beaverton, OR,USA), and a peristaltic pump with dual pumpheads (Model 7519-15, Cole Palmer, VernonHills, IL, USA) was used to process licoricedrink samples. K type dual channel digitalthermocouples (Fisher Scientific, Pittsburgh,PA, USA) were used for the monitoring of PEFtreatment temperature during the processingbefore and after each pair of PEF treatmentchamber.

PEF processing parameters were 17 (PEF1),23 (PEF2) and 30 kV/cm (PEF 3) electric fieldstrength, 3 microsec pulse duration with 500pps frequency and 148 is total treatment time.

Heat treatment of licorice drinkHeat processing of licorice drink samples wereperformed at water bath adjusted to 70 (H1),80 (H2) and 90 (H3) ◦C for 3 min, and thesamples were cooled down to refrigerationtemperature by immersing them in ice.

Combination of mild heat and PEF pro-cessingFresh drink samples were heated at 40 ◦C for 3min and then PEF processing (MH+PEF) at 23kV/cm, 3 µs pulse duration, 500 pps frequencyand 148 µs total treatment time was applied.

Measurement of physical propertiespH, total soluble solid (TSS), and conductivitymeasurements were performed by an OrionperpHectlogR meter (Inolab WTW, Germany),a digital refractometer (Nippon Optical WorksCo. Ltd, Japan), and a hand held conductivitymeter (Sension 5 model, HACH, CO, USA),respectively. Results for titratable acidity werecalculated as g/100mL citric acid. Color pa-rameters of L*, a* and b* values were measuredusing a Hunter ColorFlex spectrophotometer

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(Hunter Associates Laboratory Inc., Reston VA,USA). Total antioxidant capacity (TAC) mea-surement was conducted by DPPH method(Evrendilek, 2017); whereas total phenolic sub-stance content (TPCS) expressed in milligramsper mL gallic acid equivalents (mg GAE/mL)was conducted by Folin-Ciocalteu method (Ab-dullakasim et al., 2007).

Enumeration of microbial reductionAppropriate dilutions of both control and PEF-treated samples were plated into McConkeysorbitol agar (MCSA), xylose deoxycholate dex-trose (XLD) agar, plate count agar (PCA), andpotato dextrose agar (PDA) for E. coli O157:H7,S. Enteritidis, total aerobic mesophilic bacteria(TMAB) and total mold and yeast (TMY) bythe surface plating method, respectively. WhileMCSA, XLD and PCA plates were incubatedat 35 ± 2 ◦C for 24-48 h, PDA plates wereincubated at 22 ± 2 ◦C for 3-5 days; and theresults were expressed in log cfu/mL.

Sensory analysesBoth control and PEF-treated samples wereevaluated using a 9-point hedonic scale forthe sensory properties of color, taste, clarity,sweetness and sourness. The samples wereassigned with 3-digit numbers and served atroom temperature. Sensory analyses wereconducted in two phases. Panelists (30 people)were asked to evaluate the samples first byappearance and then by drinking. They werealso asked to consume the unsalted cracker,and drink the water in-between evaluations ofeach sample to clean their palate.

Data analysesStatistical data analyses were performed usingMinitab 16.1 (Minitab, Inc., State College, PA).Tukey’s multiple comparison tests followingone-way analysis of variance (ANOVA) wereperformed to determine significant mean dif-ferences in the response variables.


Measurement of physical properties revealedthat no significant difference was observedamong control, PEF1, PEF2, PEF3 andMH+PEF samples for pH, conductivity andTAC (p ≤ 0.05). Although heat treated sampleshad higher TA values than the rest of the sam-ples, no significant difference was observedamong the other samples (p > 0.05). While TSSof the samples among the treatments showedsome fluctuations revealing that TSS valuesof PEF processed samples were more closerto both control and MH+PEF treated samples;no significant difference was detected themexcept for H3 samples. TSS value for H3 sam-ples was significantly lower than the rest of thesamples, but it was not significantly differentfrom both H1 and H2 (p > 0.05). Except forH2 and H3 samples for color L* value, andH1, H2 and H3 samples for color a* value; nosignificant difference was observed among thesamples (p > 0.05). Color a* value, on the otherhand, showed no significant difference amongthe samples (p > 0.05). Increased temperaturecaused more degradation on the initial TPSC,and thus, both H2 and H3 samples had signifi-cantly lower TPSC than that of the rest of thesamples (p ≤ 0.05) (Table 1).

Comparison of PEF and heat pasteuriza-tion on physicochemical properties and flavourcompounds of apple juice revealed that PEFwas superior over heat processing for thepreservation of measured properties (Aguilar-Rosas et al., 2007). Similarly, PEF provided bet-ter pH preservation than HTST as the thermaltreatment showed an increase in this physico-chemical property. Moreover, some variabilitywas observed in terms of color for all the treat-ments (Charles-Rodriguez et al., 2007).

All applied processes were effective to re-duce initial number of TMY, TMAB and inoc-ulated cultures of E. coli O157:H7 and S. En-teritidis. Initial number of TAMB bacteria oflicorice drink was 6.3±0.42 log cfu/mL, andthis number significantly reduced to 3.8±0.24,2.6±0.48, 0.88±0.16, 3.9±0.36, 2.3±0.26, and0.00±0.00 log cfu/mL by PEF1, PEF2, PEF3,

99


H1, H2, H3 and MH+PEF process, respec-tively (p ≤ 0.05) (Fig. 1). Similar resultswere also obtained on the inactivation of initialTMY count. Initial TMY number of 6.9±0.62

log cfu/mL reduced to 2.6±0.22, 2.00±0.18,0.1±0.02, 3.2±0.16, 2.12±0.32, 0.00±0.00 and0.00±0.00 log cfu/mL by PEF1, PEF2, PEF3,H1, H2, H3 and MH+PEF, consequently (p ≤0.05) (Fig. 1).

100


Inactivation of E. coli O157:H7 cells re-vealed that initial number of 6.8 log cfu/mLdecreased to 5.23±0.38, 4.32±0.40, 1.27±0.22,6.32±0.50, 5.16±0.35, 2.08±0.32 and 0.3±0.08log cfu/mL by PEF1, PEF2, PEF3, H1, H2,H3 and MH+PEF, respectively (p ≤ 0.05) (Fig.1). Initial number of S. Enteriditis (6.42±0.28log cfu/ml) reduced to 4.94±0.22, 4.24±0.33,0.86±0.08, 5.32±0.49, 4.46±0.40, 1.54±0.18 and0.24±0.08 log cfu/mL by the same processes(p ≤ 0.05) (Fig. 1). It was revealed that bothPEF3 and H3 were effective for microbial in-activation; however some physical propertiesof licorice drink were affected adversely by H3treatment.

Fruit juices and fermented drinks, due totheir high acidity, are generally accepted as safebecause foodborne pathogens cannot survive.However, unlike most foodborne pathogenicbacteria, E. coli O157:H7 is able to survive inacidic foods including juices such as apple

juice, and thus, The National Advisory Com-mittee on Microbiological Criteria for Foods(NACMCF) of the United States Department ofAgriculture (USDA) reported that non-thermalpreservation technologies including PEF to en-sure the scientific criteria for pasteurization ofjuices is a 5-log reduction of the microorgan-ism(s) of public health significance (NACMCF,2006). PEF3 processing of licorice drink pro-vided 5.53 and 5.56 log reductions on the initialnumber of E. coli O157:H7 and S. Enteriditis;whereas H3 process provided 4.72 and 4.88 logreductions on both bacteria. Combination ofMH+PEF, on the other hand, provided 6.5 and6.18 log cfu/mL reductions on E. coli O157:H7and S. Enteriditis even though applied heatand electric field strength were lower than thatof H3 and PEF3 (Fig 1). Similar results werealso reported by Evrendilek (2017) that combi-nation of MH+PEF provided more inactivationon bacterial load on pomegranate juice.

Sensory properties of color, taste, clarity,sweetness and sourness are less affected byPEF processing, and thus, no significant dif-ference was observed between the control andPEF processed (PEF1, PEF2 and PEF3) samples

(p > 0.05), on the other hand, as the tempera-ture of heat treatment increased sensory scoresof the samples decreased (p ≤ 0.05). Samplestreated by MH+PEF had sensory scores closerto control samples, and therefore, no signif-

101


icant differences was detected (p> 0.05) (Fig.2).

Due to the differences in processing param-eters, changes in sensory properties of PEF-treated juice have had inconsistent results ofinsignificant and significant differences. Whileeither significant enhancement or no significantchanges in the sensory properties for peachnectar was observed (Evrendilek et al., 2016);PEF treatment (34 kV/cm for 60 µs at 55 ◦Coutlet temperature) did not significantly differfrom thermal treatment under combined mildheat and PEF in terms of sensory quality whenapplied to the fruit smoothie (50% pineapple,28% banana, 12% apple, 7% coconut, 3% or-ange juice) (Walkling-Ribeiro et al., 2010).

III. Conclusions

Processing of licorice drink by PEF and heatprovided significant amount of reduction not

only on endogenous microbial load but alsoon inoculated pathogenic bacteria of E. coliO157:H7 and S. Enteritidis important for micro-bial safety of licorice drink. On the other hand,heat treatment with increased processing tem-perature caused significant changes on somephysical as well as sensory properties. Combi-nation of mild heat much lower than the H1,H2 and H3 processes and PEF with lower elec-tric field strength than PEF1, PEF2 and PEF3resulted in better preservation of physical andsensory properties and significant degree ofmicrobial inactivation revealing that PEF aloneor combination of mild heat with PEF are bothviable options to process licorice drink. Thisstudy revealed that licorice drink can success-fully be processed by PEF, but future studiesneed to be performed with shelf-life extensionof licorice drink processed by PEF or MH+PEF.


The authors would like to thank General Directorate of Agricultural Research and Policies (TAGEM)for supporting the project entitled Application of Innovative Food Processing Technologies forFood Quality and Safety on Traditional Drink (Project no: TAGEM/16/AR-GE /35).

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ISSN: 2408-0675

Vol4 (1) International Journal of Foods and

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