Differences between the content of phenolic compounds in Criollo, Forastero and Trinitario cocoa seed (Theobroma cacao L.)

Phenolic compounds contribute to the quality of raw cocoa, the basis of all chocolate products. Detailed research is needed about the variability of these substances in unprocessed cocoa seed and during seed processing. For the present study, seed samples of Upper Amazon Forastero, Lower Amazon Forastero, Nacional, Criollo and Trinitario from different origins were compared in order to estimate the influence of genetic and site-specific features on the phenolics. Besides ripe, fresh cocoa seed, different fermentation stages of Criollo samples were analysed. Total polyphenols were examined using Folin-Ciocalteu reagent. RP-HPLC-PDA was adapted to analyse the monomeric cocoa polyphenols. Criollo seed contains no anthocyanins, but greater amounts of caffeic acid aspartate than samples of other cocoa types. No genetically determined differences in the amounts of total polyphenols and (-)-epicatechin were found. In contrast, soil fertilisation may lead to cocoa seed with significantly smaller amounts of total polyphenols, flavan-3-ols and anthocyanins, but larger quantities of caffeic acid aspartate than those from unfertilised locations. The diminution of catechins found during fermentation and drying is stronger in the Criollo seed samples than described for other genotype groups. This may be responsible for the mild flavour of Criollo chocolates. Caffeic acid aspartate turned out to be highly resistant to degradation, with an average of 33% of the original content remaining in fully fermented cocoa seed. The results could be used in trials to produce raw cocoa with specific contents of phenolics.