Cocoa beans, theobromine

Theobromine (3,7-dimethylxanthine), which is 1.2% in cocoa, provides a stimulating effect, which is less than that of caffeine in coffee. Therefore, it is of physiological importance. Caffeine is also present, but in much lower amounts (average 0.2%). A cup of cocoa contains 0.1 g of theobromine and 0.01 g of caffeine. Theobromine crystallizes in the form of small rhombic prisms which sublime at 290 °C without decomposition. In cocoa beans theobromine is often weakly bound to tannins and is released by the acetic acid formed during fermentation of the beans. Part of this theobromine then diffuses into the shell. 

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. 

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. 

Although low levels of methylxanthines have been detected in the leaves and flowers of T. cacao, the primary storage location is within the seed or bean.16 The cocoa bean is the major natural source of the methylxanthine theobromine, but contains only small amounts of caffeine. Theophylline has been detected in cacao beans, but at such low concentrations that its presence generally is ignored. Together, theobromine and caffeine account for up to 99% of the alkaloid content of T. cacao beans. Alkaloid content is affected by genetic makeup, maturity of beans at harvest, and fermentation process. Analytical methodology also is partially responsible for some of the disparity in methylxanthine values since many early methods were unable to separate theobromine and caffeine. 

The combination of ground cocoa beans and sugar produces a very hard substance with an unpleasant mouthfeel. However, the addition of extra cocoa butter results in a product that melts easily in the mouth. Additionally, the production of cocoa butter results in a lower fat cocoa powder which can be used more readily in both beverages and foods. As the amounts of cocoa butter and other fats, milk solids, sugar, and other ingredients increase, the amount of theobromine and caffeine in the final product decreases. 

Consumption of sweet chocolate in the U.S. is low. The majority of chocolate consumed is milk chocolate produced from chocolate liquor, sugar, cocoa butter, and milk solids. Because most milk chocolate produced in the U.S. contains 10 to 12% chocolate liquor, differences in methylxanthine content among commercial milk chocolate are due more to the varieties and blends of cocoa bean (Table 9). Based on analytical data from seven brands of commercial milk chocolate, a typical 40-g milk chocolate bar contains approximately 65 mg theobromine and less than 10 mg caffeine.28 Milk chocolate bars containing other ingredients, such as peanuts, almonds, and confectionery fillings, obviously contain less methylxanthines. In a survey of 49 marketed chocolate and confectionery products, theobromine concentrations ranged from 0.001 to 2.598% and caffeine content from 0.001 to 0.247%.33... 

Humphries, E., Changes in fat and theobromine content of the kernel of the cocoa bean during fermentation and drying, Rep. Cocoa Res. Trinidad, 8, 34, 1939. 

Timbie, D., Sechrist, L., Keeney, P., Application of high pressure liquid chromatography to the study of variables affecting theobromine and caffeine concentrations in cocoa beans, J. Food Sci., 43, 560, 1978. 

Alkaloids such as caffeine and theobromine were obtained from cocoa beans and guarana seeds (Saldana and others 2002a,b). 

Mohamed RS, Saldana MDA, Zetzl C, Mazzafera P and Brunner G. 2002. Extraction of caffeine, theobromine, and cocoa butter from Brazilian cocoa beans using supercritical CO2 and ethane. Ind Eng Chem Res 41(26) 6751-6758. 

Extracts of coffee bean and cocoa bean have been produced experimentally that contained about 3% of caffeine and 3% theobromine respectively without the disadvantage of flavour concentration typically associated with those raw materials. These are potentially alternative natural sources of effective stimulants to guarana and kola. Other supplementary herbs that have a place in energy... 

Chocolate has antioxidant properties for low-density lipoproteins and hence could prevent heart disease. Foods and beverages derived from cocoa beans have been consumed by humans since 460 a.d. Cocoa pods from the cocoa tree (Theobroma cacao) are harvested and the beans removed and fermented. Dried and roasted beans contain about 300 chemicals including caffeine, theobromine, and phenethylamine. Chocolate liquor is prepared by finely grinding the nib of the cocoa bean and is the basis for all chocolate products. Cocoa powder is made by removing part of the cocoabutter from the liquor. Bittersweet chocolate, sometimes called dark chocolate, contains between 15 and 60% chocolate liquor, the remainder being cocoa butter, sugar, and other additives. Milk chocolate is the predominant form of chocolate consumed in the U.S. and typically contains 10 to 12% chocolate liquor. 

Roasting cocoa beans results in the production of volatile and non-volatile compounds which contribute to the total flavor complex. 5-Methyl-2-phenyl-2-hexenal, which exhibited a deep bitter persistant cocoa note, was reported in the volatile fraction (53). It was postulated to be the result of aldol condensation of phenylacetaldehyde and isovaleraldehyde with the subsequent loss of water. The two aldehydes were the principal products of Strecker degradation products of phenylalanine and leucine, respectively. Non-volatiles contained diketopiperazines (dipeptide anhydride) which interact with theobromine and develop the typical bitterness of cocoa (54). Theobromine has a relatively stable metallic bitterness, but cocoa bitterness is rapidly noticed and disappears quickly. 

Caffeine occurs in both tea (3.5%) and coffee and is normally manufactured from coffee and tea dust and similarly theobromine is the main purine of the cocoa bean from which it may be prepared. Caffeine has also been manufactured from guanine by hydrolysis to xanthine followed by methylation with methyl acetate or dimethyl sulfate (46USP2509084). 

Methylxanthine is the major purine constituent of human urine (3.1 g in 1000 L). 3- and 7-Methylpurines are also minor constituents of urine, especially following large doses of caffeine or other methylated xanthines. 1,3-Dimethylxanthine (theophylline) occurs with caffeine in tea leaves and is a powerful diuretic. It has been used clinically in the treatment of asthma. The main purine constituent of the cocoa bean is 3,7-dimethylxanthine (theobromine). 1,2,7-Trimethylxanthine (caffeine) is the major purine of the coffee bean and also occurs in tea leaves (3.5%). It acts as a cardiac and respiratory stimulant. Caffeine can be extracted from the natural source by extraction with hot water. ... 

The two alkaloids theobromine and theophylline are isomeric, theobromine being the 3-7-di-methyl xanthine and theophylline the I-3-di-methyl xanthine. Theobromine is the principal alkaloid of the cocoa bean. Cacao theohroma. It occurs also in small amounts in kola nuts and tea leaves. Theophylline is present in small amounts in tea. They both resemble caffeine in being crystalline, weak bases. 

Other key derivatives, xanthine (2,6-dihydroxypurine, 4) and hypoxanthine (6-hydroxypurine, 5), are formed by the hydrolytic decomposition of nucleic acids. As their systematic names indicate, the well-known CNS stimulants caffeine (1,3,7-trimethylxanthine, 6), theophylline (1,3-dimethylxanthine), and theobromine (3,7-dimethyl-xanthine), found in coffee, tea, and cocoa beans, respectively, are all derived from xanthine. 

The amount of theobromine in cocoa beans varies widely, ranging from to 40 milligrams of theobromine per gram... 

Theobromine is usually obtained from the hulls of cocoa beans left over after the production of chocolate. The hulls... 

The natural products theophylline 34 (1,3-dimethylxanthine), theobromine 35 (3,7-dimethylxanthine) and caffeine 36 (1,3,7-trimethylxanthine) are derived from the lactam form of xanthine. Theophylline occurs in tea leaves and is a diuretic and a coronary vasodilator. Cocoa beans contain ca. 5% theobromine, which is a stronger diuretic than theophylline or caffeine. 

Triacanthine (17) has been isolated from Holarrhena mitis Details on the structure and total synthesis of eritadenine (18), a hypocholesterolemic alkaloid from Lentinus edodes, have been reported.An unsuccessful attempt to improve the imidazole ring-closure reaction in a total synthesis of eritadenine, which has been previously discussed, was also reported in this study. Concentrations of both caffeine and theobromine in the cocoa bean were shown to increase most markedly in the time period from flowering to harvest. ... 

Caffeine is also found in tea leaves from Camellia sinensis (up to 5 %) and in the seeds of cola nuts (Cola nitida, up to 2 %). Mat6 (Paraguay tea. Ilex para-guariensis, with 0.3-1.5%) and the seeds of the cocoa plant (Theobroma cacao, with 0.05%) show a significantly lower content. The main alkaloid in cocoa beans is theobromine. 

Fig. 2.36 The coffee shrub and its berries, cocoa beans and tea flowers. Shown below are the 3D molecular models of caffeine, theobromine and theophylline. The difference between the chemical structures is the number and position of methyl groups (highlighted by dark shacMng). (Authors own work and copyright-free pictures from the book Bessette, Alan E., Chapman, William K. (eds.) Plants and flowers. 1761 Illustrations for artists and designers. Dover Publications, Inc., New York, 1992)...

These three alkaloids are well-known compounds, as they are present in everyday foods and beverages, such as cocoa, drinking chocolate, tea, and cola, as well as in pharmaceutical products. In cocoa products, theobromine is the major alkaloid, followed by caffeine, which is found in small quantities. Slight traces of theophylline have been identified therefore, it is not considered relevant and is not reviewed in the cocoa products [22,23], The range of methylxanthines also depends on variables such as the origin of the cocoa beans, the fermentation process, and the cocoa production process. Thus, for instance, defatted cocoa beans may contain about 4% and 0.2% of theobromine and caffeine, respectively [24], Regarding their physiological effects in humans, methylxanthines have been related to various body systems, mainly the central nervous system, but also the cardiovascular, renal, and respiratory systems [25,26],... 

Senanayake UM, Wijesekera ROB (1971) Theobromine and caffeine content of the cocoa bean during its growth. J Sci Food Agric 22 262-263... 

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