Cocoa organisms found

Of the organic acids (1.2-1.6%), citric, acetic, succinic and malic acid contribute to the taste of cocoa (Table 21.23). They are formed during fermentation. The amount of acetic acid released by the pulp and partly retained by the bean cotyledons depends on the duration of fermentation and on the drying method used. Eight brands of cocoa were found to contain 1.22-1.64% total acids, 0.79-1.25% volatile acids and 0.19-0.71% acetic acid. 

Many organic compounds are obtained from natural sources through extraction. This method takes advantage of the solubility characteristics of a particular organic substance with a given solvent. In the experiment here, caffeine is readily soluble in hot water and is thus separated from the tea leaves. Caffeine is one of the main substances that make up the water solution called tea. Besides being found in tea leaves, caffeine is present in coffee, kola nuts, and cocoa beans. As much as 5% by weight of the leaf material in tea plants consists of caffeine. 

In modem medicine, mily the purified opium alkaloids and their derivatives are commonly employed. Although the ripe poppy capsule can contain up to 0.5 % total alkaloids, opium represents a much concentrated form and up to 25 % of its mass is composed of alkaloids. Of the many (>40) alkaloids identified, some six represent almost all of the total alkaloid content. Actual amounts vary widely, e.g., morphine (4-21 %), codeine (0.8-2.5 %), thebaine (0.5-2.0 %), papaverine (0.5-2.5 %), noscapine (narcotine) (4—8 %), and narceine (0.1-2 %). A t3q>ical commercial sample of opium would probably have a morphine content of about 12 %. Powdered opium is standardized to contain 10 % of anhydrous morphine, usually by dilution with an approved diluent, e.g., lactose or cocoa husk powder. The alkaloids are largely combined in salt form with meconic acid, opium containing some 3-5 % of this material. Meconic acid is invariably found in opium but, apart from its presence in other Papaver species, has not been detected elsewhere. It gives a deep red-colored complex with ferric chloride, and this has thus been used as a rapid and reasonably specific test for opium. Of the main opium alkaloids, only morphine and narceine display acidic properties, as well as the basic properties due to the tertiary amine. Narceine has a carboxylic acid function, while morphine is acidic due to its phenolic hydroxyl. This acidity can be exploited for the preferential extraction of these alkaloids (principally morphine) from an organic solvent by partitioning with aqueous base (Table 15.6). 

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