Cocoa beans

The name Theobroma cacao, food of the gods, indicating both the legendary origin and the nourishing quaUties of chocolate, was bestowed upon the cacao tree by Linnaeus in 1720. All cocoa and chocolate products are derived from the cocoa bean, the seed of the fmit of this tree. Davila Garibi, a contemporary Mexican scholar, has traced the derivation of the word from basic root words of the Mayan language to its adoption as chocolate in Spanish ( ) ... 

The terms cocoa and cacao often are used interchangeably in the Hterature. Both terms describe various products from harvest through processing. In this article, the term cocoa will be used to describe products in general and the term cacao will be reserved for botanical contexts. Cocoa traders and brokers frequendy use the term raw cocoa to distinguish unroasted cocoa beans from finished products this term is used to report statistics for cocoa bean production and consumption. 

The cocoa bean is the basic raw ingredient in the manufacture of all cocoa products. The beans are converted to chocolate Hquor, the primary ingredient from which all chocolate and cocoa products are made. Eigure 1 depicts the conversion of cocoa beans to chocolate Hquor, and in turn to the chief chocolate and cocoa products manufactured in the United States, ie, cocoa powder, cocoa butter, and sweet and milk chocolate. 

Significant amounts of cocoa beans are produced in about 30 different locaUties. These areas are confined to latitudes 20° north or south of the equator. Although cocoa trees thrive in this very hot climate, young trees require the shade of larger trees such as banana, coconut, and palm for protection. 

Fermentation (Curing). Prior to shipment from producing countries, most cocoa beans undergo a process known as curing, fermenting, or sweating. These terms are used rather loosely to describe a procedure in which seeds are removed from the pods, fermented, and dried. Unfermented beans, particularly from Haiti and the Dominican RepubHc, are used in the United States. 

The age-old process of preparing cocoa beans for market involves specific steps that allegedly promote the activities of certain enzymes. Various methods of fermentation are used to the same end. 

Table 1. Main Varieties of Cocoa Beans Imported into the United States...

Cocoa beans are sometimes evaluated in the laboratory to distinguish and characterize flavors. Beans are roasted at a standardized temperature for a specific period of time, shelled, usually by hand, and ground or heated slightly to obtain chocolate Hquor. The Hquor s taste is evaluated by a panel of... 

Blending. Most chocolate and cocoa products consist of blends of beans chosen for flavor and color characteristics. Cocoa beans may be blended before or after roasting, or nibs may be blended before grinding. In some cases finished Hquors are blended. Common, or basic beans, are usually African or BraziUan and constitute the bulk of most blends. More expensive flavor beans from Venezuela, Trinidad, Ecuador, etc are added to impart specific characteristics. The blend is deterrnined by the end use or type of product desired. 

Production. Worldwide cocoa bean production has increased significantly over the past 10 years from approximately 1.6 million t in the 1979—1980 crop year to over 2.4 million t in 1990. The production share by country has also changed dramatically in the last 10 years. The big gainers are Malaysia, Indonesia, and the Ivory Coast. The large gains in Malaysia and Indonesia have helped to diversify production and partially shield the market from adverse weather-induced supply shocks. The biggest losers in production share have been Brazil and Ghana. Table 2 Hsts production statistics for these countries. 

Consumption. Worldwide cocoa bean consumption has increased significantly over the past 10 years from approximately 1.5 million t in the 1979—1980 crop year to almost 2.3 million t today. This growth was uneven between East and West. North America and Western Europe increased grind by approximately 200% over this time period whereas Russia and Eastern Europe dropped 11%. Table 3 gives the aimual tonnage of cocoa bean grind by the United States and other leading countries. 

Marketing. Most of the cocoa beans and products imported into the United States are done so by New York and London trade houses. The New York Sugar, Coffee, and Cocoa Exchange provides a mechanism by which both chocolate manufacturers and trade houses can hedge their cocoa bean transactions. Additional information on the functions of the New York Cocoa Exchange is available (3). 

Chocolate Hquor is the soHd or semisohd food prepared by finely grinding the kernel or nib of the cocoa bean. It is also commonly called chocolate, unsweetened chocolate, baking chocolate, or cooking chocolate. In Europe chocolate Hquor is often called chocolate mass or cocoa mass. 

Gleaning. Cocoa beans are imported in the United States in 70-kg bags. The beans can be processed almost immediately or stored for later use. They are usually fumigated prior to storage. 

Although flavor precursors in the unroasted cocoa bean have no significant chocolate flavor themselves, they react to form highly flavored compounds. These flavor precursors include various chemical compounds such as proteins, amino acids, reducing sugars, tannins, organic acids, and many unidentified compounds. 

The natural moisture of the cocoa bean combined with the heat of roasting cause many chemical reactions other than flavor changes. Some of these reactions remove unpleasant volatile acids and astringent compounds, partially break down sugars, modify tannins and other nonvolatile compounds with a reduction in bitterness, and convert proteins to amino acids that react with sugars to form flavor compounds, particularly pyrazines (4). To date, over 300 different compounds, many of them formed during roasting, have been identified in the chocolate flavor (5). 

Table 4. Analyses of Cocoa Shell from Roasted Cocoa Beans...

Grinding. The final step in chocolate Hquor production is the grinding of the kernel or nib of the cocoa bean. The nib is a cellular mass containing about 50 to 56% cocoa fat (cocoa butter). Grinding Hberates the fat locked within the cell wall while producing temperatures as high as 110°C. 

The FDA has not legally defined cocoa butter, and no standard exists for this product under the U.S. Chocolate Standards. For the purpose of enforcement, the FDA defines cocoa butter as the edible fat obtained from cocoa beans either before or after roasting. Cocoa butter as defined in the US. Pharmacopeia is the fat obtained from the roasted seed of Theohroma cacao Uinne. 

The Codex Committee on Cocoa and Chocolate Products defines cocoa butter as the fat produced from one or more of the following cocoa beans, cocoa nibs, cocoa mass (chocolate Hquor), cocoa cake, expeUer cake, or cocoa dust (fines) by a mechanical process and/or with the aid of permissible solvents (10). It further states that cocoa butter shall not contain sheU fat or germ fat ia excess of the proportion ia which they occur ia the whole bean. 

Siace cocoa butter is a natural fat, derived from different varieties of cocoa beans, no single set of specifications or chemical characteristics can apply. Codex has attempted to define the physical and chemical parameters of the various types of cocoa butter (14) (Table 5). 

Table 11. Composition of Cocoa Beans and their Products, Whole Weight Basis in %...

Table 12. Vitamin Content of Various Samples of Cocoa Beans and Chocolate Products, Whole Weight Basis, mg/100 g...

Table 14. Fatty Acid Composition of Raw Cocoa Beans and Cocoa Butter ...

Expression Dewaterings of Fibrous Materials. Fibrous materials are frequently dewatered in belt-filter, screw, disk, and roU presses and in batch pot and cage presses. Table 1 Hsts appHcations of screw, roU, and pot presses. Screw and high pressure belt presses are continuous and have replaced batch pot and cage presses in most appHcations. Traditionally, however, batch presses have been used for squee2ing cocoa butter from cocoa beans, which require pressures up to 41 MPa (6000 psi) (39). A description of many types of batch presses is included in Reference 40. 

Kakao, m. cacao cocoa, -baum, m. cacao, cacao tree, -bohne, /. cacao bean, cocoa bean, -butter, /. cacao butter, cocoa butter, -masse,/, cocoa i aste. -ol, n. cocoa (cacao) oil or butter, -pulver, n. cocoa powder. 

Li13 developed a method for the individual determination of caffeine and theobromine in cocoa beans. Cocoa bean samples are ground as finely as possible (less than 0.5-mm diameter particles), the powder is boiled in... 

HPLC allows a quantitative determination with relatively simple extractions. In many cases, extraction only involves a heating of the commodity with water, followed by filtration and injection onto an HPLC column. In the determination of caffeine, theobromine, and theophylline in cocoa, coffee, or tea, as well as in other foods, there is scarcely a month that passes without a new paper on this assay. Kreiser and Martin provide typical conditions for analysis.28 In their studies, samples were extracted in boiling water and filtered prior to injection onto the HPLC column. The HPLC conditions used a Bondapak reversed phase column and a mobile phase of water methanol acetic acid (74 25 1) with detection at 280 nm. This method is accurate, precise, and conserves time. It has also been adopted by the AOAC as an official method for the determination of theobromine and caffeine in cocoa beans and chocolate products.29... 

Li, S., Berger, J., Hartland, S., UV spectrophotometric determination of theobromine and caffeine in cocoa beans, Analytics Chimica Acta, 232,409,1990. 

Horwitz, W., Ed., Cocoa bean and its products, HPLC method, in Official Methods of Analysis of AOAC, 13th ed., AOAC, Washington, D.C., 1980, p 382. 

Foods derived from cocoa beans have been consumed by humans since at least 460 to 480 AD. The source of cocoa beans, the species Theobroma, contains a variety of biologically active components. These include the purine alkaloids theobromine, caffeine, and theophylline. Structurally, they are methylated xanthines and, thus, are often referred to as methylxanthines. Theobromine (3, 7-dimethylxanthine) is the predominant purine alkaloid in cocoa and chocolate. Caffeine (1, 3, 7-trimethylxanthine), the major purine alkaloid found in coffee and tea, is found in cocoa and chocolate at about one eighth the concentration of theobromine. Only trace amounts of theophylline (1, 3-dimethylxanthine) are detected in cocoa and chocolate products. 

The first important technical development in the chocolate manufacturing process occurred when water-powered mills superseded the use of manual labor to grind cocoa beans. This led to the establishment of many chocolate factories from 1804 to 1840. Early production consisted entirely of a type of chocolate beverage that was somewhat indigestible since none of the cocoa butter was removed during processing. In 1828, the Dutch firm of Van Houten invented the cocoa press, which facilitated the production of cocoa powder by partial removal of the cocoa butter from beans. 

With the death of the bean, cellular structure is lost, allowing the mixing of water-soluble components that normally would not come into contact with each other. The complex chemistry that occurs during fermentation is not fully understood, but certain cocoa enzymes such as glycosidase, protease, and polyphenol oxidase are active. In general, proteins are hydrolyzed to smaller proteins and amino acids, complex glycosides are split, polyphenols are partially transformed, sugars are hydrolyzed, volatile acids are formed, and purine alkaloids diffuse into the bean shell. The chemical composition of both unfermented and fermented cocoa beans is compared in Table 1. 

---