Academia Journal of Agricultural Research 3(9): 176-183, September 2015 DOI: 10.15413/ajar.2015.0128 ISSN: 2315-7739 ©2015 Academia Publishing

Research Paper

Methods of cocoa harvesting to drying of bean in Ghana and polycyclic aromatic hydrocarbon concentration in the nib and shell of the cocoa bean

Accepted 19th May, 2015 ABSTRACT As cocoa and its products continue to attract high patronage due to its outstanding characteristics, prevention of contamination in all of its parts resulting from unapproved practices becomes imperative. This study was conducted to assess the primary practices adopted by cocoa farmers in Ghana during harvesting to storage of cocoa beans through personal and questionnaire interviews of cocoa farmers in five of the cocoa districts of Ghana and also to identify the concentrations of cocoa contaminating-compounds, Polycyclic aromatic hydrocarbons (PAH) including benzo[a]pyrane, in the nib and shell which are potential stores of PAH through mass spectroscopic analysis. Results indicated that although cocoa farmers adopted standard procedures, some practices, mainly drying of the bean in kitchen vicinity, which promote build-up of PAH in the beans occurred. Contamination occurred in higher concentration in the shell (63.03%) than in the nib (36.07%). Accumulation of PAH in the nib at over half that of the shell is quite worrisome, since it suggests that the extent at which the activities that may advance availability of PAH could be so high to overcome the protection offered to the nib. This calls for intensification of educational programmes on best practices in harvesting and processing of the bean. Key words: Cocoa, polycylic aromatic hydrocarbons, contamination, nib, shell

INTRODUCTION Cocoa, the dried and fully fermented fatty seed of the cacao tree, described as the food of the gods, is much treasured by people all over the world because of some outstanding characteristics which cannot be found in any other product. It has been termed "the food of the gods," literally, a translation of Theobroma cacao, the cacao bean. It was believed that the Mexican god Quetzalcoatl left the cocoa tree for the people. The extent of treasure may be exemplified in its products such as chocolate, which, in its many forms, has been enjoyed for over 2,000 years and its effects lauded. The Aztec emperor Montezuma is reported to have consumed fifty (50) goblets of chocolate in each

day. Many people consider chocolate as un-substitutable. Cocoa has many constituents and therefore exhibits very

complex chemical properties. Among these properties, those imparted by certain components mainly fat, Theobroma, caffeine, and salsolinol share the strongest desirous attribute by people. For instance, the body’s natural intense desire for fat and sugar and the addictive tendency which is promoted by caffeine are some of the attributes of components of cocoa. In spite of this, relatively low quantity of caffeine, a compound the consumption of which is strictly required to be moderated, is noted in cocoa products such as chocolate. The Theobroma in cocoa

G. Owusu-Boateng1* and S. K. Owusu2 1Faculty of Renewable Natural Resources, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. 2Akuafo Adamfo Marketing Company Limited, Ghana. *Corresponding author. E-mail: goow@aqua.dtu.dk

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generally weakens the stimulatory effects it exhibits.

The global importance of cocoa has been embraced by many countries including Ghana. In Ghana cocoa is a central cohesive source of support and stability for the economy, excelling through its hallmark of employment and foreign exchange generation since its introduction into the country several years ago. Ghana is rated among the major important cocoa-producing nations in the world together with countries such as Cote d’lvoire, Brazil, Malaysia, Indonesia, Nigeria and the Cameroon.

Cocoa continues to be a very important cash crop that has come under critical scrutiny in terms of the concentrations of its potential contaminating-compounds. Again, due to cocoa’s ability to drive national economies cocoa-producing nations continue the strive to gain greater acceptance in the world market. This underpins the dynamism of the standards set for its production. To gain international acceptance, cocoa-producing nations including Ghana have been developing strategies such as education to ensure maintenance of good quality standing. However, the industry is not without challenges. Prominent among these challenges are diseases and pests infestation, lack of policy framework to sustain production, processing, consumption and promotion and intensification of cocoa extension all of which do not only limit production quantity but also quality.

One of the quality-related issues of much concern is the production of cocoa with moderate concentration of polycyclic aromatic hydrocarbons (PAHs) also termed Polynuclear aromatic hydrocarbons, that is acceptable to both internal and external consumers (especially the European Union countries). PAHs, a very important compound in cocoa is a group of organic contaminants with two or more benzene rings (National Research Council, 1994), formed from incomplete combustion of hydrocarbons, such as coal and gasoline (Van Metre et al., 1996). They are usually by-products of petroleum processing or combustion. Many of these compounds are highly carcinogenic at relatively low levels (Eaton et al., 2005). They range in appearance from colourless to white or pale yellow-green. Although they are useful in areas of research, manufacture of dyes, plastics, pesticides and medicines, they do not burn very easily and therefore they can stay in the environment for long periods of time. This persistence, together with their omnipresence explains the cause of concern associated with their development. At excess dose beyond the body requirement, PAH may cause health disorders such as infertility, foetal damage retarded growth, low birth weight and disruption of endocrine systems.

Sources of PAHs are both natural and anthropogenic. The latter is by far the major contributor. Natural sources include forest fires (Blumer and Youngblood, 1975), volcanic eruptions (Ilnitsky et al., 1977), and degradation of biological materials, leading to the formation of these compounds in various sediments and fossil fuels (White

and Lee, 1980). Lesage and Jackson (1992) observed that burning of coal refuse dumps, production of coke, automobiles, commercial incinerators, and wood gasifers are other anthropogenic sources. Contamination by PAH is promoted through combustion of refined petroleum products (e. g. emission from train, vehicular traffic and industrial operations), natural and intentional burning of biomass fuels, uncontrolled and accidental input of unburned organics. Mediums and processes such as water, soil and air, and smoking and drying respectively provide routes for PAH contamination.

Chocolate addiction may cause negative effect such as craving, anxiety, and even depression (Tuomisto et al., 1999). The WHO (2005), reported symptoms including eye irritation, vomiting, convulsion and nausea as some of the results of occupational exposure to high levels of pollutant mixtures containing polycyclic aromatic hydrocarbon. SCF (2002) observed breakdown of red blood cells upon inhalation of or ingested in large amounts of PAH particularly Naphthalene. A genotoxic effects has been reported in the cells of humans and other mammals (WHO, 1998). The European Union countries form a major group of consumer of Ghana’s cocoa. To protect public health, the EU has set a maximum level for benzo[a]pyrene (B[a]P), the most toxic and carcinogenic (ATSDR, 1995) in foods (EC Regulation 208/2005). This maximum is 2 ppb in vegetable oil and fats, for direct consumption or used as an ingredient in food. The EU limit is not only applicable to EU produce but also to imports into the EU. The implication of this action by the EU is rejection of consumable cocoa products that have PAH level exceeding 2 ppb. As one of the product quality variables, PAH has been placed at the spotlight in recent times due to its heath concerns.

Given the background that various stages namely collection of pods, breaking of pods, fermentation of beans, drying of beans, bagging and storage and transportation for shipment cause various levels of contaminants into the products, it is essential to improve post-harvest practices to reduce PAH contamination and avoid a serious negative impact on the economies of producing countries. This will contribute to improving the quality of produced cocoa consumed internally and externally.

As the health concerns associated with PAH continues to rise amidst global expectation of increasing production of cocoa, the need for research into the various components of the bean that potentially serve as store of this contaminant. This will enable remediation efforts to be well directed hence achieve effective solution. METHODOLOGY The sample frame for the survey followed a multi-stage sampling procedure in which specific major domains were distinguished for tabulation of important characteristics. To achieve this, the cocoa regions and districts in Ghana were

Academia Journal of Agricultural Research; Boateng and Owusu. 178 first identified. The cocoa regions were designated as high, medium and low as defined by production levels. Five (5) of these cocoa regions were purposively selected based on stratified sampling design to reflect the three designations. The effects of sampling and non-sampling errors were not overlooked in determining the sample size. With such background knowledge, an operationally manageable sample size was taken for the study; a total sample of hundred (100) cocoa farming societies nationwide formed the actual study farm sample from 10 cocoa districts which were in turn carefully selected from the five cocoa regions of interest.

The communities, villages and cocoa farms in the selected sampled area were visited for a survey of cocoa processing and storage methods adopted by farmers. Personal and questionnaire interviews were the main survey tools employed. Personal observations were also made as a support to the above tools. Activities of interest included methods of harvesting of cocoa pods, transport and gathering of the pods to a central location, removal of the cocoa beans, fermentation and subsequent drying of the cocoa beans.

Determination of PAH levels in cocoa beans (nib and shell)

Samples of cocoa bean were taken for analysis of PAH concentration in the nib and shell. The method of analysis involved separation of the nib and hells of 10 g of the samples cocoa beans. This was followed by weighing of each component (nib and shell). Each component was crushed separately at low temperature and homogenised using Na2SO4 as drying agent. Soxhlet extracts using hexane was obtained and post extract cleaned with calcium gel. The extracts were concentrated using the rotary evaporator method and subjected to mass spectroscopic analysis. Results were subjected to the t-test (P < 0.05). Data collected was analyzed with the Statistical Package for Social Sciences (SPSS).

RESULTS AND DISCUSSION

Methods of primary processing and storage of cocoa beans

Sixty-seven (67) cocoa districts in the country from the seven (7) cocoa regions in Ghana (Ashanti, Brong Ahafo, Central, Eastern, Western North, Western South and Volta) were identified. The various broad stages and units of operations in the primary processing of the cocoa bean through which respondents (farmers) takes their cocoa, as identified in this study may be illustrated sequentially in a flow chart:

Harvesting and gathering of ripe pods

Pod opening

Fermentation of beans

Drying of beans

Storage of beans in bags

Dispatch for export. This is in conformity with standard practice (Mikkelsen, 2010).

Harvesting and gathering of ripe pods

Firstly, the cocoa pods were harvested from the various cocoa trees, loaded in baskets, transported and gathered at a central location. These activities were described by farmers as being labour-intensive. Harvesting and processing of cocoa beans are very delicate and also labour intensive processes. Only pods that are ripe, identified by their yellow or red colours, were harvested by farmers. Green pods indicated that they were not ripe and were therefore left on the trees unharvested. Farmers took special precautions to prevent possible damage to fruit-making flowers and buds that were close to targeted pods. Flowers and pods of plants are delicate and easy to break or become bruised. The tendency exists for injury to be caused to the cocoa pods which in turn promote fungi infestation (Vos et al., 2003; Mossu, 1992). The harvested pods were immediately collected from the floor to prevent damage by rodents and other animals and were grouped into the following classes: healthy, diseased and damaged. The processes through which the cocoa bean from healthy harvested pod were processed began with periodic (weekly during peak seasons) gathering of the pods using large baskets. Head-loads are carried to a designated destination where they were piled up and made ready for splitting of the pods to remove the beans. This identified procedure is very labour-intensive sometimes requiring involvement of whole families.

Pod opening

The gathered pods were opened to remove the wet cocoa beans (Plate 1). This was done not later than the fourth day. The process involved hand-splitting using a thick piece of wood or a wooden mallet to expose the white pulp or mucilage covered beans. Farmers (100%) explained that this facilitates fermentation, the next stage, which precedes

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Plate 1. Opening of harvested cocoa pods. drying of the cocoa beans and contributes to flavor development in the bean. Like the harvesting and gathering stage, this procedure is also very labour-intensive. Most often, farmers dwelled on whole family (sometimes including school children) together with friends and neighbours during this stage. Are and Gwynne-Jones (1974) observed that opening the pods is a slow and a labour-intensive process. Although this is a profitable step since the use of children may reduce cost, the possibility of promoting child labour as well as child slavery and child trafficking cannot be ruled out (WACAP, 2003). The average number of seed or beans in each opened cocoa pod was 40. Gu et al. (1990) observed a range of 30 to 40 beans per pod while Tan (2013) observed an average of 36.6 beans per pod (Plates 2 and 3). Farmers noted that the use of machetes and other sharp tool could cause damage to the cocoa bean. Ninety-eight (98%) of farmers discarded broken beans. They were then carried to the place designated for fermentation. Several studies have shown the beneficial use of empty cocoa pods e. g. for preparation of composting for making fertilizers or substrates on which mushrooms may be grown (Owusu-Boateng and Dzogbefia, 2005) and for making potash which is used for manufacturing of soap by the women in the community. This notwithstanding, most farmers left most of the pods on the farm. This may serve as suitable habitat for the

microorganisms which attach the cocoa trees. Fermentation Lehrian and Patterson (1983) noted that, there is no flavour in cocoa beans without fermentation. Wood and Lass (1985) noted fermentation as one of the major cocoa beans processing steps. The cocoa beans consisted of seed coat, a kernel and a germ. Farmers gather the fresh beans into heaps usually on banana leaves (Plates 4 and 5) at a dry place and covered (Plates 6) and left for 2 to 7 days a duration dictated by a number of factors including weather conditions such as temperature (Özdemir and Devres, 2000; Le, et al., 2001; Demir, 2002). Fermentation is affected by factors including the type temperature (Binh Phan Thanh (2003), quality and quantity of beans and pulp, degree of ripeness of the cocoa pods, storage practices, duration of fermentation, seasonality and climate. Mossu (1992) and Amoa-Awua (2007) recounted the difficulty and non-homogeneous nature of cocoa bean fermentation. Nielsen et al. (2007) indicated the inadequacy of understanding of microbial fermentation. Five or more days of fermentation may cause lowering of acidity and lower acidity results in better bean quality. Majority of farmers (88.1%) usually allowed 5-day fermentation, 16.5%

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Plate 2. Opened cocoa pods.

Plate 3. Fresh cocoa beans removed from their pods.

Plate 4. Freshly removed cocoa beans.

Plate 5. Cocoa bean being prepared for fermentation heaped on banana leaves.

Plate 6. A heap of cocoa beans covered to hasten fermentation.

allowed 6-day and 3.4 allowed 7-day.

Periodic stirring of the heaped beans boosts fermentation. In this, 84.3% of farmers stirred the heap on every third day while 15.7% stirred on every second day. During fermentation, micro-organisms mainly yeast transfer by insects such as Drosophila melanogaster or vinegar-fly grow on the pulp of the beans and convert the sugars in the pulp surrounding the beans to ethanol. This bacteria action causes temperature rise to between 40 and 45oC during the first two days. Acetic acid penetrates through the husk to initiate biochemical reactions in the bean. The elevated temperatures break cell walls or testa (husk) and disrupt internal cellular structure. This sets up a complex chemical changes in the bean to cause flavour (chocolate) and colour development. The content of water reduces from a range of 82-87% to 32-39%. Longer period

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Plate 7. Drying of cocoa beans near smoke, a possible source of PAH contamination.

of fermentation results in well-developed aroma (Liu et al., 2014). Drying of cocoa bean After fermentation, farmers dried the cocoa beans. Several methods of drying including natural and artificial methods may be used to dry the cocoa bean (Dano et al., 2013). They include fire under a tray and the use of rusty artificial dryers (Samoa type). The use of industrial artificial dryers namely; static, vertical and rotary dryers have also been adopted in various places but the study identified sun-drying, a natural method as the main method adopted by cocoa farmers. Temperature significantly influences most of the physical and chemical properties of the cocoa beans. The aroma and brown colour imparted to the bean, release of water, volatile acids and tannin compounds and the resistance to microbial attack are all attributes of roasting (Benz, 2002, Lee et al., 2001: Redgwell et al., 2003). Although sun-drying, a method that decreases acidity (Guehi et al., 2010) astringency and bitterness was the method employed by cocoa farmers, they occurred at different locations and distances from possible sources of cocoa bean contaminations such as kitchen vicinity (Plate 7).

The listed available drying methods have varying degrees of success and output in terms of quality of the product. The effectiveness and efficiency of the methods may be related to their respective abilities in drying the cocoa beans without introduction of potential contaminants mainly PAHs. In this study, it was observed that the beans were spread on special woven mat of plant origin mounted on a board at a height of about 1 m above the ground. The

effectiveness of drying was found also to be linked to the surface area exposed (Bharath and Bowen-O’Connor, 2007; Sukha, 2009). Although the beans were stirred periodically, thicker depths reduced effectiveness of drying of the bean. The number of days required for effective drying varied again, according to the weather conditions of the area. In the forest regions moist climate posed a great challenge during drying. In the Western Region where the atmosphere remains relatively humid for a longer period, six (6) days while in the Ashanti Region with relatively lower humidity 4 to 5 days were enough for effective drying. In protecting the drying cocoa beans against rains, especially in the night, farmers adopted precautionary measures. Farmers spread polyethylene material over the cocoa beans on days when rainfall appeared to be likely. PAH concentration of nib and shell of cocoa bean Although some uncertainties exist in relation to the accuracy of benzo[a]pyrane as a general indicator for overall PAH contamination and the selection of food groups specified in the regulation by the European Communities and the European Food Safety Authority, the compound has been used for such purpose with high degree of success. PAH contamination was higher in the shell than in the nib. The recorded PAH concentrations were (63.03%) and (36.07%) respectively (Figure 1) and differed significantly at (P< 0.05). This observation is not surprising since the orientation of the parts of cocoa bean is such that the shell is relatively more exposed, occurring at the external part of the nib and therefore might absorb most of the PAH-induced compound in the vicinity of the bean. Moreover, the shell may offer some degree of protection to the nib

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Figure 1. Mean concentrations of PAH components in the shell and nib of cocoa bean.

against PAH penetration (Eboua, et al., 2011; Lowor et. al., 2012).

These may suggest that the nib has stronger structures and mechanism of protection of cocoa against PAH contamination than the shell (Lowor et al., 2012). The cocoa flavour precursors are developed into chocolate flavour by roasting the dried, deshelled beans or nibs, in particular through Maillard reactions (Ziegleder and Biehl, 1988: Ziegleder, 1991). In-spite of the ability of the shell to protect the nib to some extent, from contamination the influence of effective drying practice remains a pre-requisite. In situations where no adequate attention is given the chosen drying method and practices, poor quality bean have been reported, although the quality of the raw cocoa may primarily influence the product. Conclusion Cocoa farmers in the study area generally adopted standard procedures during harvesting of cocoa and processing of the cocoa beans in spite of the improper citation of drying destinations which promote contamination of the bean, mainly the shell and especially the nib to an unusually high degree. The generally labour-intensive nature of harvesting and processing of the cocoa beans could contribute to some of the improper practices adopted.

REFERENCES

Amoa-Awua W, Madsen M, Takramah JF, Olaiya A, Ban-Koffi l, Jakobsen M

( 2007). Quality manual for production and primary processing of

cocoa. Unpublished MSc Thesis Department of food science, University of Copenhagen.

Are LA, Gwynne-Jones DRG (1974). Cacao in West Africa. Chapter 10: Harvesting and processing of Cocoa. IBADAN, Oxford University Press, Oxford, England.

Agency for Toxic Substances and Disease Registry (1995). Toxicological profile for polycyclic aromatic hydrocarbons (PAHs). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Benz K (2002). Debacterization of cocoa beans gains increasing acceptance. http://www.buhlergroup.com/sc/en/publikationen.asp

Bharath S, Bowen-O’Connor C (2007). Assessing drying rates of cacao beans using small samplets. Annual report (2007). Cocoa Research unit. U. W. I. St. Augustine, Trinidad. pp. 52 – 58.

Thanh BP (2003). Research on some factors affecting fermentation and bean quality in small fermentation, The Western Highlands Agro-Forestry Scientific and Technical Institute

Blumer M, Youngblood WW (1975). Polycyclic aromatic hydrocarbons in soils and recent sediments. Science, 188, p. 53.

Dano, SD, Manda P, Dembélé A, Abla AMK, Bibaud, JH, Gouet JZ, Sika CBZ (2013). Influence of Fermentation and Drying Materials on the Contamination of Cocoa Beans by Ochratoxin A. Toxins, 5, 2310-2323; doi:10.3390/toxins5122310

Demir AD, Celayeta JMF, Cronin K, Abodayeh K (2002). Modelling of kinetics of colour change in hazelnuts during air roasting. Journal of Food Engineering, 55(4): 283-292.

Eaton AD, Clesceri LS, Rice WE, Greenberg AE, Franson MAH (2005). Standard methods for the examination of water and wastewater, 21st edition. Washington (DC): American Public Health Association, American Water Works Association, Water Environment Federation.

Guehi TS, Bi Zahouli I, Ban-Koffi L, Fae MA, Nemlin JG (2010). Performance of different drying methods and their effects on the chemical quality attributes of raw cocoa material. International Journal of Food Science and Technology. 45, 1564–1571

Eboua NW, Elleingand EF. Ndouba AM (2011). A screening for benzo[a]pyrène in cocoa beans subjected to different drying methods during on farm processing. International Journal of Engineering Science and Technology, 3(5): 3621-3630

Gu F, Tan L, Wu H, Fang Y, Xu F, Chu Z, Wang Q (2013). Comparison of Cocoa Beans from China, Indonesia and Papua New Guinea. Foods, 2013, 2, 183-197.

Ilnitsky AP, Gvildis VY, Myshchenko VS (1977). Of the volcano role in the

Academia Journal of Agricultural Research; Boateng and Owusu. 183 formation of natural background of carcinogens. Addresses of Academy of

Sciences USSR 234(3), 717-719 (Ru). Lee SY, Yoo SS, Lee MJ, Kwon IB (2001). Optimization of nibs roasting in

cocoa bean processing with Lottebetter taste and color process. Food Sci. Biotechnol. 10, 286-293.

Lehrian DW, Patterson GR (1983). Cocoa fermentation, in Biotechnology, a Comprehensive Treatise, 5, ed. by Reed G.

Lesage S, Jackson R E (1992). Groundwater contamination and analysis at hazardous waste sites: Marcel Dekker, Inc., 552 p.

Liu X, Liu J, Yang Z, Song H, Liu Y. Zou T (2014). Aroma-active compounds in jinhua ham produced with different fermentation periods Molecules, 19, 19097-19113.

Lowor ST, Jacquet M, Vrielink T, Aculey P, Cros E. Takrama J. (2012). Post-harvest sources of polycyclic aromatic hydrocarbon contamination of Cocoa beans: A simulation. International Journal of AgriScience, 2(11): 1043-1052.

Mossu G (1992). Cocoa. Chapter 6: Harvesting and preparation of commercial cocoa. The Macmillan press ltd. London, United Kingdom.

National Research Council, 1994. Alternatives for Groundwater Cleanup, National Academy Press, Washington, DC.

Nielsen D.S, Teniola OD, Ban-Koffi L, Owusu M, Andersson TS. Holzapfel WH (2007). The microbiology of Ghanaian cocoa fermentations analysed using culture-dependent and culture-independent methods. Int J Food Microbiol 114, 168–186.

Owusu-Boateng, G. Dzogbefia VP (2005). Establishing optimum parameters for the cultivation of oyster mushrooms on cocoa pod husk. J. Ghana science association 7 (1) 1-7.

Özdemir M, Devres YO (2000). Analysis of colour development during roasting of hazelnuts using response surface methodology. Journal of Food Engineering, 45(1): 17-24.

Redgwell RJ, Trovato V, Curti D (2003). Cocoa bean carbohydrates: roasting-induced changes and polymer interactions. Food Chem. 80, 511-516.

Scientific Committee on Foods of EC (2002). Opinion of the Scientific Committee on Food in the risk to human health of PAHs in food. Brussels: SCF.

Sukha DA (2009). Innovations in solar drying of the fine or flavour cocoa bean. The cocoa research unit. Presentation from “Cocoa sector Technical forum”, Kingston and St. Mary, Jamaica,

Tan GY ( 2013). Combining Ability Analysis of Yield and Its Components in Cacao. J. Amer. Soc. Hort. Sci., 115(3):509-512. 1990.

Tuomisto JT, Viluksela, M, Pohjanvirta R, Tuomisto J (1999). The AH receptor and a novel gene determine acute toxic responses to TCDD:

segregation of the resistant alleles to different rat lines. Toxicol. Appl. Pharmacol., 155 pp. 71–81.

Vos JGM, Ritchie BJ, Flood J (2003). Discovery learning about cocoa. An inspirational guide for training facilitators. CABI Bioscience, UK

WACAP (2003). West Africa Cocoa and Commercial Agriculture, Project Report, 2003

White CM, Lee ML (1980). Identification and geochemical significance of some aromatic components of coal: Geochimica et Cosmochimica Acta, 44, p. 1825.

Wood GAR, Lass, RA (1985). Cocoa, 4th edn. Longman Inc., New York. World Health Organization (2005). Summary and Conclusions of the Sixty-

Fourth Meeting of the Joint FAO/WHO Expert Committee on Food Additives, World Health Organization: Rome.

World Health Organization (1998). Environmental health criteria 202, selected non-heterocyclic PAHs, Geneva

Mikkelsen L (2010). Quality assurance along the primary processing chain of cocoa beans from harvesting to export in Ghana. Unpublished MSc Thesis. University of Copenhagen.

Ziegleder G (1991).Composition of flavor extracts of raw and roasted beans. Z Lebensmitt Unters-Forsch 192:521–525

Ziegleder G, Biehl B (1988). Analysis of cocoa flavour compounds and precursors, in Modern methods of plant analysis, 8, ed. by Linkskens H.F & Jackson J.F. Springer, Berlin, pp. 361–393.

Cite this article as: Owusu-Boateng G, Owusu SK (2015). Methods of cocoa harvesting to drying of bean in Ghana and polycyclic aromatic hydrocarbon concentration in the nib and shell of the cocoa

bean. Acad. J. Agric. Res. 3(9): 176-183. Submit your manuscript at http://www.academiapublishing.org/journals/ajar