Fresh cocoa beans contain about 32–39% water, 30–32% fat, 10–15% protein, 5–6% polyphenols, 4–6% pentosans, 2–3% cellulose, 2–3% sucrose, 1–2% theobromine, 1% acids and less than 1% caffeine. It is also a rich source of mineral components.
The polyphenols in cocoa beans could contribute to about 12-18% of the dry weight of the whole bean.
The content and composition of polyphenols differs depending on the genotype, origin, growth conditions, degree of ripeness of the cocoa fruit and the grain processing parameters.
Studies indicated that dark chocolate exhibited the highest polyphenol content, with 610 mg total catechins/kg of fresh edible weight. With advancements in technology, high performance liquid chromatography (HPLC) had been utilized in the determination of polyphenol compounds in cocoa.
Main classes of polyphenolic compounds identified are such as simple phenols, benzoquinones, phenolic acids, acetophenones, phenylacetic acids, hydroxycinnamic acids, phenylpropenes, coumarines, chromones, naphtoquinones, xanthones, stilbenes, anthraquinones, flavonoids, lignans and lignins. Three main groups of cocoa polyphenols can be distinguished namely the catechins (37%), anthocyanins (4%) and proanthocyanidins (58%).
The brown and purple color of the cocoa bean was attributed to the complex alteration products of catechin and tannin. Beside these compounds, cocoa was found to have leucoanthocyanins that are present as glycosides.
Phenolic antioxidants have been shown to inhibit the oxidation of low-density lipoprotein (LDL) cholesterol, and mounting evidence suggests that it is the oxidized form of LDL that leads to the buildup of fatty plaques in arteries.
Some other the beneficial effects of polyphenols are such as anti-carcinogenic, anti-atherogenic, anti-ulcer, anti-thrombotic, anti-inflammatory, immune modulating, anti-microbial, vasodilatory and analgesic effect.
Epicatechin and other flavonoids not only have a direct antioxidant effect, but they may also have a sparing effect on other antioxidants such as Vitamin C and E.
Organic compounds in cocoa -polyphenols 
