Fate of proanthocyanidins and anthocyanins along fermentation of cocoa seeds (Theobroma cacao L.)

Abstract

Condensed tannins, also called proanthocyanidins, play a substantial role in the sensory characteristics of chocolate. Little is known about their fate along fermentation. In the present study, location and behavior of tannins in the cotyledons and testae of cocoa seeds are studied during fermentation by light and transmission electron microscopy. Tannins along with anthocyanosides were also measured. Tannins are located in special tanniferous cells from both cotyledons and testae of native seeds. The most striking phenomena occurring during fermentation are an almost complete disappearance of the testa tannins and, in the cotyledons, a translocation without losses of the tannins from the tanniferous cells towards surrounding tissues. Quantitative analyses confirm these observations and show that little oxidation of the cotyledonary tannins occurs. The anthocyanosides from the cotyledons completely disappear. It is assumed that this translocation could hinder proteolysis of the cotyledon proteins by formation of resistant tannin-protein complexes.