Food Science and Technology Project Topics

Proximate Composition of Solar Dried Cocoa Bean Powder

Proximate Composition of Solar Dried Cocoa Bean Powder

Proximate Composition of Solar-Dried Cocoa Bean Powder

Chapter One

The Objective of the Study

Therefore the aim of this research is to evaluate the proximate composition of solar dried cocoa bean powder.



History of Cocoa Bean (Theobroma Cacao L)

The cacao tree is native to the Amazon Basin. It was domesticated by the Olmecs and Mokaya (Mexico and Central America). More than 4,000 years ago, it was consumed by pre-Columbian cultures along the Yucatán, including the Maya, and as far back as Olmeca civilization in spiritual ceremonies. It also grows in the foothills of the Andes in the Amazon and Orinoco basins of South America, in Colombia and Venezuela. Wild cacao still grows there. Its range may have been larger in the past; evidence of its wild range may be obscured by cultivation of the tree in these areas since long before the Spanish arrived (Kaufman and Justeson, 2006).

As of November 2018, evidence suggests that cacao was first domesticated in equatorial South America, before being domesticated in Central America roughly 1,500 years later (Kaufman and Justeson, 2006). Artifacts found at Santa-Ana-La Florida, in Ecuador, indicate that the Mayo Chinchipe people were cultivating cacao as long as 5,300 years ago (Kaufman and Justeson, 2006). Chemical analysis of residue extracted from pottery excavated at an archaeological site at Puerto Escondido, in Honduras, indicates that cocoa products were first consumed there sometime between 1500 and 1400 BC. Evidence also indicates that, long before the flavor of the cacao seed (or bean) became popular, the sweet pulp of the chocolate fruit, used in making a fermented (5% alcohol) beverage, first drew attention to the plant in the Americas (Bingham and Roberts, 2010). The cocoa bean was a common currency throughout Mesoamerica before the Spanish conquest (Wood and Lass, 2001).

Cacao trees grow in a limited geographical zone, of about 20° to the north and south of the Equator. Nearly 70% of the world crop today is grown in West Africa. The cacao plant was first given its botanical name by Swedish natural scientist Carl Linnaeus in his original classification of the plant kingdom, where he called it Theobroma (“food of the gods”) cacao.

Cocoa was an important commodity in pre-Columbian Mesoamerica. A Spanish soldier who was part of the conquest of Mexico by Hernán Cortés tells that when Moctezuma II, emperor of the Aztecs, dined, he took no other beverage than chocolate, served in a golden goblet. Flavored with vanilla or other spices, his chocolate was whipped into a froth that dissolved in the mouth. No fewer than 60 portions each day reportedly may have been consumed by Moctezuma II, and 2,000 more by the nobles of his court (Díaz-del-Castillo, 2005).

Chocolate was introduced to Europe by the Spaniards, and became a popular beverage by the mid-17th century. Spaniards also introduced the cacao tree into the West Indies and the Philippines. It was also introduced into the rest of Asia and into West Africa by Europeans. In the Gold Coast, modern Ghana, cacao was introduced by a Ghanaian, Tetteh Quarshie (Díaz-del-Castillo, 2005).

Varieties of Cocoa (Theobroma cacao L)

The three main varieties of cocoa plant are Forastero, Criollo, and Trinitario. The first is the most widely used, comprising 80–90% of the world production of cocoa. Cocoa beans of the Criollo variety are rarer and considered a delicacy (Díaz-del-Castillo, 2005).Criollo plantations have lower yields than those of Forastero, and also tend to be less resistant to several diseases that attack the cocoa plant, hence very few countries still produce it. One of the largest producers of Criollo beans is Venezuela (Chuao and Porcelana). Trinitario (from Trinidad) is a hybrid between Criollo and Forastero varieties. It is considered to be of much higher quality than Forastero, has higher yields, and is more resistant to disease than Criollo (Díaz-del-Castillo, 2005).

    Cultivation of Cocoa (Theobroma cacao L)

A cocoa pod (fruit) has a rough, leathery rind about 2 to 3 cm (0.79 to 1.18 in) thick (this varies with the origin and variety of pod) filled with sweet, mucilaginous pulp (called baba de cacao in South America) with a lemon like taste enclosing 30 to 50 large seeds that are fairly soft and a pale lavender to dark brownish purple color (Zipperer, 2002).

During harvest, the pods are opened, the seeds are kept, and the empty pods are discarded and the pulp made into juice. The seeds are placed where they can ferment. Due to heat buildup in the fermentation process, cacao beans lose most of the purplish hue and become mostly brown in color, with an adhered skin which includes the dried remains of the fruity pulp. This skin is released easily by winnowing after roasting. White seeds are found in some rare varieties, usually mixed with purples, and are considered of higher value (Fabricant, 2011).

 Harvesting of cocoa

Cocoa trees grow in hot, rainy tropical areas within 20° of latitude from the Equator. Cocoa harvest is not restricted to one period per year and a harvest typically occurs over several months. In fact, in many countries, cocoa can be harvested at any time of the year (Woodand Lass, 2001). Pesticides are often applied to the trees to combat capsid bugs, and fungicides to fight black pod disease (Abenyega and Gockowski, 2003).

Immature cocoa pods have a variety of colours, but most often are green, red, or purple, and as they mature, their colour tends towards yellow or orange, particularly in the creases (Wood and Lass, 2001; Hui, 2006). Unlike most fruiting trees, the cacao pod grows directly from the trunk or large branch of a tree rather than from the end of a branch, similar to jackfruit. This makes harvesting by hand easier as most of the pods will not be up in the higher branches. The pods on a tree do not ripen together; harvesting needs to be done periodically through the year (Wood and Lass, 2001). Harvesting occurs between three and four times weekly during the harvest season (Wood and Lass, 2001).

The ripe and near-ripe pods, as judged by their colour, are harvested from the trunk and branches of the cocoa tree with a curved knife on a long pole. Care must be used when cutting the stem of the pod to avoid damaging the junction of the stem with the tree, as this is where future flowers and pods will emerge (Wood and Lass, 2001; Dand, 1999). One person can harvest an estimated 650 pods per day (Abenyega and Gockowski, 2003; Gockowski and Oduwole, 2003).




 Sample Preparation

Riped cocoa pods (mixed hybrids) were obtained from the Cocoa Research Institute in Akure, Ondo State. Cocoa pods of uniform ripeness were harvested by traditional methods (under ambient temperature during the day; 28-30°C) and transported to a fermentary (on the cocoa plantation) where they were stored. The respective pods were then split to remove the seeds and fermented using the traditional basket fermentation method. About 30 kg of extracted cocoa beans were placed in woven baskets lined with banana leaves. The surface were also covered with banana leaves and fermented for six days with consecutive opening and turning every 48 hrs (Bartley, 2005)

Drying cocoa bean using solar dryer

The samples were loaded into the dryer and weighed on a top pan balance with a precision of 0.1g. The drying was conducted for 72 hours with rest periods at nights, from 6 pm to 6 am. Traditionally, cocoa beans are dried for 5-6 days and the product is often infested with mould and slate. The moisture content of the beans was measured every six hours during the drying process. Also, where possible, the experimental samples were evaluated against the International Standard for dried cocoa beans.




Table 4.1: Proximate Composition of Solar dried Cocoa bean Powder





The study was based on the effects of solar dryer on proximate composition of cocoa beans, it observed in the study that solar dried cocoa bean contain quality amounts of fat and crude fibre, the ash content as shown in the table above is low (1%) this might be attributed to the effects of solar on cocoa bean quality during drying. Cocoa bean has been revealed by researchers to contain less protein compared to other sources of protein.


Based on the study above it is therefore recommended that researcher should be carried out on how to prevent the nutritional quality of cocoa bean during solar drying especially protein and ash content of the cocoa bean.


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