Food Science and Technology Project Topics

Mineral Composition of Solar-Dried Cocoa Bean Powder

Mineral Composition of Solar Dried Cocoa Bean Powder

Mineral Composition of Solar-Dried Cocoa Bean Powder

Chapter One

The Objective of the Study

The aim and Objectives of this study are to determine the effects of solar drying on the mineral composition of the cocoa bean.



History of Cocoa (Theobroma cacao)

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.

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 (Binghamet al.,2010). Artifacts found at Santa-Ana-La Florida, in Ecuador, indicate that the MayoChinchipe people were cultivating cacao as long as 5,300 years ago (Binghamet al.,2010). 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 (Wood and Lass, 2001). 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°C 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 (Díazdel Castillo, 2005).

 Varieties of Cocoa

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 (Spadaccini, 2002).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(Spadaccini, 2002).

 Cultivation of Cocoa

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 lemonade-like taste enclosing 30 to 50 large seeds that are fairly soft and a pale lavender to dark brownish purple color.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 (Florence, 2011; Zipperer, 2002).



Materials and Methodology

Sample Preparation

Ripe 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.

Solar drying

Solar drying is the method in which the sun’s heat is managed and utilized for drying while protecting for the product. The samples, loaded into the dryer were 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. The traditional sun drying of some sample was also employed simultaneously, to provide for comparisons. Also, where possible, the experimental samples were evaluated against the International Standard for dried cocoa beans.




Table 4.1: Mineral Composition of Sundried Cocoa Bean





In conclusion, our findings indicate that cocoa bean is a good source of sodium, potassium, magnesium, phosphorus, and calcium, compared to iron, manganese, copper and lead, though the value of minerals depends on methods of drying. Solar-drying is an artificial method of drying, the sun’s heat is managed and utilized for drying while protecting for the product.


It is therefore recommended that the use of solar-drying method should be practice, as it helps to retain some essential mineral elements in cocoa bean.


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