Download - Nano edible coating of fruits and vegetables
Welcome
Ind
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Agric
ultu
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esea
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Insti
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, New
Del
hi Seminar (VSC 691)
Division of Vegetable Science ICAR-Indian Agricultural Research Institute
New Delhi-110012
Gajanan A.G.20594
Nano coatings : A novel approach for improving the shelf life of vegetables
India is the second largest producer of fruits (81.2 million
tonnes) and vegetables (162.1 million tonnes) in the world
(Horticulture data base, 2013)
But about 20 to 30% of the produce is lost annually due to lack
of adequate infrastructure and limited use of modern postharvest
technologies.
Fresh fruits and vegetables have short shelf life because of high
respiration rate, moisture content, bulky in nature and pathogen
attack.
Introduction
Critical factors involved in post harvest longevity
Maturity stage
Temperature
Water loss
Ethylene
Mechanical damage
Post harvest Diseases
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Methods to prolong shelf life
Shelf life
Pre cooling
Sorting, Grading
Post harvest
treatments
Packaging
MA/ CA Storage
Minimal Processing
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Nanotechnology
Nanotechnology ?..
“Design, Characterization, Production and application of structures, devices and systems by controlling the shape and size at the nanometer scale”.
Mousavi and Rezaei, 2011
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Ind
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Agric
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Insti
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, New
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Father of NanotechnologyNobel Laureate – 1965Richard Feynman, Physicist, America
The term ‘ Nanotechnology’ Coined in
1974 by Norio Taniguchi of the Tokyo.
Properties of Nanoparticles Nano-scale materials show unusual physical, chemical and biological
properties. (Li et al., 2001)
Nanoparticles have large surface to volume ratio (Kumar et al., 2010)
Magical changes takes place at Nano level
Physical Surface area, conductivity, charge capacityChemical Reactivity
Mechanical strength
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Why we need Nanotechnology ???
To enhance the efficiency of available post harvest technologies
To reduce the economics of additives.
Ethylene biosynthesis inhibitors – AVG,AOA : Expensive and
Phytotoxic
Many chemicals which we are using may be soon banned due to
their environmental impact
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Nano-coating
Nano-sensors
Nano-packaging
Post harvest Management
Nano technologies- Vegetable crops
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COATINGS
Conventional coating
Nano coating Nano particle coating
Nanoemulsion coating
Zinc oxide:
Titanium dioxide:
Silver nanoparticles
• Antimicrobials
• Anti-ethylene agents
• Extend shelf life in carrot , Asparagus ( Jianshen, 2008 )
Antibacterial activity
E.coli contamination in foods
Nano particles - Few Examples
“NS release Ag+ (Lok et al., 2007), which has been reported to interact with cytoplasmic components and nucleic acids, to inhibit respiratory chain enzymes and to interfere with membrane permeability” Russell and Hugo,1994; Park et al., 2005
NANOEMULSION COATING“ Nanoemulsion consist of an lipid nano droplets (between 10 – 100 nm diameter ) dispersed in an aqueous solution and each oil droplet surrounded by surfactant molecules with unique physicochemical and functional characteristics” - Acosta (2009).
Functions of Nano coating
• Acts as a Natural layer to prevent moisture loss.
• Selectively allow controlled exchange of O2 & Co2
• Prevent the loss of important components- vitamins & minerals.
• May impart functional components: Antimicrobial; ethylene scavengers.
Effect of Alginate/ nano-Ag coating on microbial and physicochemical characteristic of shitake mushroom (lentinus edodes)
Jiang et al. (2013)
Food Chemistry
Case Study 1
Objectives To determine the effect of the alginate/nano-Ag coating
on the microbial and physicochemical characteristics of shiitake mushrooms, during storage at 4° C for 16 days.
Mushroom• Second most cultivated edible mushroom
• Why mushrooms are Highly Perishable Higher moisture content Lack epidermal structure. Extremely High respiration rate Higher PPO activity Susceptible to microbial spoilage
Pseudomonas tolaasii & Pseudomonas fluorescens yeasts - Candida sake
• Sodium alginate 1.5 %• AgNO3 (0.1 M) – Anti-microbial agent • NaBH4 (0.01 M) - • PVP (0.01 M) - • Glycerol – Plasticizer • Calcium chloride – Cross linkage.
Materials And Methods
(1) Control – simply Dissolved in water (2) Alginate coating(3) Alginate/nano-Ag coating
Treatment
Microbial count of nano-coated shitake mushrooms during storage
Modes of action of silver nanoparticles on bacteria
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Sukumaran Prabhu and Eldho K Poulose., 2012
Weight loss of nano-coated shitake mushrooms during storage
4.1%
< 2.5%
Firmness of nano-coated shitake mushrooms during storage
Loss of firmness is due to degradation of cell wall by bacterial enzymes and hence alginate acts as antibacterial compound
Reducing sugar (A), Total sugar (B), Total soluble solids (C), and Electrolyte leakage rate (D) in coated shitake mushroom
31.7
Coated sample maintain high membrane integrity hence less electrolyte leakage
16.5
Inference • Alginate/nano-Ag coating had beneficial effects on the physicochemical and physiological quality
compared to the control treatment.
• Weight loss, softening, and browning in the alginate/nano-Ag coated mushrooms were significantly inhibited after 16-days storage.
• Lower microbial counts, including mesophilic, psychrophilic, pseudomonad, and yeasts and moulds, in treated mushrooms during storage
• Reducing sugar (5.4%), total sugar (34.9%) for nanocoated mushrooms while total soluble solids (19.04% and electrolyte leakage rate (12.04%) for the alginate/nano-Ag coating comapred to control mushroom over 16 days storage.
• Slightly lower CO2 and higher O2 concentrations were recorded for nano-coated mushrooms indicating lower rate of respiration.
• Therefore, the alginate/nano-Ag coating could be applied for preservation of the shiitake mushroom to expand its shelf life and improve its preservation quality.
Antibacterial and physical effects of modified chitosan based-coating containing nanoemulsion of mandarin essential oil and three non-thermal treatments against Listeria innocua in green beans
Severino et al.(2014)
International Journal of Food Microbiology
Case Study 2
Objective- • To evaluate the antibacterial effects of modified chitosan-based coating
incorporating mandarin EO nanoemulsions in combination with three non-thermal treatments against Listeria innocua inoculated in green beans during storage at 4 °C.
Treatments-• Coating UV-C – 0.8 j/cm2• Ozone – 7ppm , 2.5 min γ-Ray 0.25 kGy
Materials & Methods:• Fresh green beans (Phaseolus vulgaris L.)• Stock cultures of L. innocua• Mandarin essential oil• Modified chitosan (MC, 3% N-palmitoyl chitosan, degree of palmitoylation
47%)
Parameters
• Microbial analysis• Relative Inactivation value• Texture• Colour
Relative inactivation value (RIV) for the different combined non-thermal treatments tested.
Pyrimidine dimers formation in DNA
RIV
control coating UV-c ozone Ƴ ray UV-C + coating Ozone + coating γ-Ray + coating0
1
2
3
4
5
6
7
8
9Day 1 2 5 8 12 15
Micr
obia
l cou
nt (L
og cf
u/g)
Effect of coating formulation in combination with non-thermal treatments on population of L. innocua on green beans samples during storage at 4 °C.
2.3
UV-C 2.83 log cfu reduction 1 st day & 5 log cfu during 15th day of storage
control coating UV-C Ozone Ƴ ray UV-C + coating Ozone + coating γ-Ray + coating0
100
200
300
400
500
600 Day 1 5 9 12 15
Firm
ness
(N)
Effect of coating formulation in combination with non-thermal treatments on firmness of green beans samples during storage at 4 °C.
in firmness is bcz PG,cellulae
Inference
• γ-irradiation and coating combined treatment exhibiting a strong synergistic antimicrobial effect.
• UV-C combined treatment with the bioactive coating, represent an effective approach to control the growth of L. innocua on vegetable foods.
Future prospects
• The efficiency and the economic benefits of applying various techniques in combination with nanotechnology needs to be evaluated in the different vegetable crops.
• Focused research is required in use of nanoparticles to improve the quality and the post harvest life of vegetables.
Ind
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Method of preparation