Theobromine cocoa

Theobroma cocoa Chocolate Cocoa Theobromine Epicatechin Bronchoddator Usmani et al. (2004) Sanno et al. (1993)... 

These two methylated xanthines are found in quite a number of plants and have been extracted and widely used for centuries. Indeed, they very hkely have been, and remain today, the predominant stimulant consumed by humans. Every time you make a cup of tea or coffee, you perform an aqueous extraction of plant material (tea leaves. Camellia sinenis, 1 %, or coffee beans, Coffea spp., 1-2%) to obtain a dose of 25-100 mg of caffeine. Caffeine is also the active substance (—2%) in mate (used in Paraguay as a tea) made from the leaves of Ilex paraguensis. In coffee and tea, caffeine is the dominant member of the pair, whereas in Theobroma cacao, from which we obtain cocoa, theobromine (1-3%) is the primary source of the biological response. Caffeine acts to stimulate the central nervous system with its main impact on the cerebral cortex, and as it makes one more alert, it is no surprise that it is the chief constituent in No-Doz pills. 

This experiment describes a quantitative analysis for caffeine, theobromine, and theophylline in tea, pain killers, and cocoa. Separations are accomplished by MEKC using a pH 8.25 borate-phosphate buffer with added SDS. A UV detector set to 214 nm is used to record the electropherogram. An internal standard of phenobarbital is included for quantitative work. 

Two other commonly found sources of caffeine (16) are kola Cold) from the seeds of, for example. Cola nitida (Vent.) Schott and Engl., which contains 1—4% of the alkaloid, but Httie theophylline or theobromine, and cocoa (from the seeds of Theobroma cacao L.), which generally contains about 3% theobromine and significantiy less caffeine. 

Caffeine was conceived for a wide range of readers interested in the effects on human health, nutrition, and physiological function of the methylxanthine beverages and foods—tea, coffee, mate, cola beverages, and cocoa and chocolate products. These products supply one or more of the dietary methylxanthines—caffeine, theobromine and theophylline— and are an integral part of the diet of many people in many countries. The interest in the health effects of both the methylxanthines in isolation and in the products containing them has grown rapidly in recent years. 

The methylxanthines of interest are caffeine (1,3,7-trimethylxanthine), theophylline (1,3-dimethylxanthine), and theobromine (3,7-dimethylxanthine) and they occur in coffee, tea, mate, cocoa products, and cola beverages. This chapter is an introduction to their chemistry, isolation, and biosynthesis. While the class of methylxanthines is large and comprised of more members than these three, this chapter will essentially be limited to caffeine, theobromine, and theophylline. 

While caffeine biosynthesis in coffee and tea has been reasonably well investigated, little information is available about the biosynthetic pathways of methylxanthines in cacao. Published studies34 35 have established the presence of 7-methylxanthine and adenine in cocoa. Since both coffee and tea exhibit similar pathways where theobromine is a direct precursor for caffeine, it is reasonable to assume that a similar mechanism is possible in cacao. 

The analysis of the methylxanthines (caffeine, theobromine, and theophylline) is important in the areas of nutrition and clinical chemistry. These three compounds compose the majority of the alkaloids present in coffee, tea, cocoa, cola nuts, and guarana. 

There are numerous methods in the literature for the determination of caffeine, theobromine, and theophylline in food matrices, including coffee, tea, and cocoa. Until recently, methods have emphasized the determination of the major methylxanthines in a commodity, for example, caffeine in coffee or theobromine in cocoa. Present methods range from being specific for one of the compounds in a single matrix to being an all-encompassing assay of major and minor methylxanthines in food products. 

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... 

Theobromine was determined by GC in various foods (bitter chocolate, milk chocolate, chocolate cake, cocoa powder, chocolate milk), and results are given in graphs and tables.27 Homogenized samples were boiled in alkaline aqueous media, then fat was extracted with n-hexane. The aqueous layer was acidified with diluted HC1 and NaCl was added. Theobromine was extracted from this treated aqueous solution with dichloromethane and the extract was evaporated to dryness. The residue was redissolved in dichloromethane containing an internal standard. GC analysis was performed on a column packed with 1% cyclohexane dimethanol succinate on Gaschrom Q, with FID. Average recoveries were 99 to 101%, coefficient of variation was less than 3% and the limit of detection for theobromine in foods was about 0.005%. 

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... 

Moores, R.G. and Campbell, H.A., Determination of theobromine and caffeine in cocoa materials, Anal. Chem., 20,40,1948. 

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

Franzke, C.L., Grunert, K.S., and Griehl, H., Estimation and contents of theobromine and theophylline in mate, cola and cocoa. Zeitschrift fuer Lebensmitteluntersuchung und Forschung, 139,85,1969... 

Kreiser, W.R. and Martin, R.A. Jr., High pressure liquid chromatographic determination of theobromine and caffeine in cocoa and chocolate products, JAOAC, 61,1424,1978. 

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. 

In live cocoa seeds, the methylxanthines are localized in polyphenolic storage cells. Bean death, which occurs 24 to 48 h after initiation of fermentation, triggers diffusion of the methylxanthines from the nib to the shell. The early studies of Humphries state that cacao cotyledons lose about 40% of their theobromine during fermentation.17 According to Knapp and Wadsworth, the loss of theobromine and caffeine becomes significant on the third day when the methylxanthines begin to diffuse into the shell.18 This migration continues until the concentration of the methylxanthines in nibs and shell are almost equal. 

Chocolate liquor is the solid or semiplastic food prepared by finely grinding the nib of the cacao bean. It is commonly called baking chocolate, unsweetened chocolate, or bitter chocolate and, in Europe, is frequently referred to as chocolate mass or cocoa paste. Chocolate liquor is essentially the starting point from which all chocolate products are produced. Table 5 lists the theobromine and caffeine content of 22 various chocolate liquor samples determined by high pressure liquid chromatography (HPLC). The liquors averaged 1.22% theobromine and 0.214% caffeine.27- 28 The ratio of theobromine to caffeine ranged from 2.5 1 to 23.0 1. 

According to Schutz, it is well known that cocoa contains about 2.5% by weight of theobromine and caffeine.29 Although the presence of theophylline has been demonstrated, its concentration is so low that it is generally ignored. In a summary of the literature values for 27 commercial cocoa powders and cocoa masses, Hadorn found that the mean total alkaloid content was 3.36 0.48%.23 Theobromine and caffeine content of several cocoa powders is shown in Table 6. HPLC analyses by DeVries et... 

Cocoa butter is the fat obtained from subjecting chocolate liquor to pressure. Since the alkaloids are sparingly soluble in fat, only trace amounts of theobromine and caffeine in cocoa butter have been reported. The theobromine and caffeine content of four cocoa butter samples averaged 0.008% and 0.038%, respectively.33... 

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. 

Two chocolate beverages made from unsweetened cocoa contained 228 and 284 mg theobromine per serving 32 Burg reported 272 mg theobromine and 6 mg caffeine per cup of beverage made from African cocoa, and 232 mg theobromine and 42 mg caffeine for a similar beverage made with South American cocoa.34 Both beverages were prepared according to manufacturer s directions. 

Bunker and McWilliams found that two beverages prepared from instant cocoa (with Dutch process cocoa) contained 10 to 17 mg caffeine per cup.37 Table 7 lists the theobromine and caffeine concentration of hot cocoa and chocolate milk prepared from instant mixes. Zoumas et al. analyzed five commercial hot cocoa mixes and reported an average of 65 mg per serving of theobromine and 4 mg per serving of caffeine.28 Similar results were reported by Blauch and Tarka.36... 

Chocolate milk samples prepared from sweetened cocoa powders averaged 58 mg per serving of theobromine and 5 mg per serving of caffeine.28 Analysis of a "home-style" recipe resulted in higher methylxanthine values — 94 mg theobromine and 10 mg caffeine per serving. However, the authors noted that this recipe also had a stronger chocolate flavor. The lower values reported by Zoumas et al. and Blauch and Tarka compared to others was attributed to the inability of older methods to separate theobromine and caffeine, and the lack of precision and accuracy of the older methods. A compendium of theobromine and caffeine values reported for chocolate beverages from both published and unpublished studies has been compiled in Table 8. 

Theobromine and Caffeine Concentration in Hot Cocoa and Chocolate Milk Prepared From Instant Mixes... 

Most chocolate is consumed in the form of chocolate confectionery. Sweet chocolate is produced from chocolate liquor with the addition of sugar and cocoa butter. Sometimes called dark chocolate, sweet chocolate must contain at least 15% chocolate liquor, but may contain as much as 50%. Semisweet or bittersweet chocolate consists of a minimum of 35% chocolate liquor. The chocolate liquor content results in sweet and semisweet chocolate containing the highest amount of theobromine and caffeine per serving of any type of chocolate confectionery (Table 9). Within brands of sweet chocolate, there is wide variation in the methylxanthine... 

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... 

The theobromine content of chocolate foods prepared from home recipes using common chocolate sources — cocoa, semisweet baking choco-... 

Significant scientific attention has focused on caffeine and its health effects. However, limited data are available for the actual dietary consumption of caffeine or theobromine from individual foods. Even less data exist on the contribution of cocoa and chocolate foods to methylxanthine intake. 

This chapter has compiled and evaluated information on the methylxanthine composition of cocoa and various chocolate foods and beverages, as well as the consumption pattern for these commodities. Cacao is the major natural source of the xanthine base theobromine. Small amounts of caffeine are present in the bean along with trace amounts of theophylline. Numerous factors, including varietal type and fermentation process, influence the methylxanthine content of beans. 

Chocolate liquor is a semifinished product commonly called "baking" or unsweetened chocolate. The average theobromine and caffeine content of liquors has been reported at 1.2% and 0.21%, respectively. Cocoa powder, which is prepared after partial removal of the cocoa butter, contains about 1.9 to 2.7% theobromine and 0.16 to 0.26% caffeine. Milk chocolate averages 0.168% theobromine and 0.022% caffeine, thus providing about 65 mg of theobromine and less than 10 mg of caffeine in a 40-g serving. The methylxanthine content of chocolate foods has received only slight attention in the literature, yet is necessary in order to obtain an accurate assessment of the total amount of theobromine and caffeine that is ingested via the diet. 

Significant scientific attention has focused on caffeine and its health effects. However, limited data is available for the actual dietary consumption of caffeine or theobromine from individual foods. Even less data exists on the contribution of cocoa and chocolate foods to methylxanthine intake. In children and teenagers, the major dietary source of caffeine was found to be tea, followed by soft drinks and coffee, respectively. Although chocolate foods and beverages ranked the lowest of these dietary sources to provide caffeine, they do constitute the major source of dietary theobromine. In order to gain a better insight into the amount of methylxanthines consumed via the diet, more studies on the methylxanthine content of chocolate foods, as well as beverages, are needed. 

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. 

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