HINWEISE AUF DIE URSACHEN FUR DIE ANREICHERUNG VON LEUCIN, ALANIN, PHENYLALANIN UND TYROSIN UNTER DEN FREIEN AMINOSÄUREN DES FERMENTIERTEN KAKAOS

Abstract

The composition of free amino acids in fermented cocoa beans and of cocoa seeds after fermentation-like incubations has been determined by RP-HPLC. Leucine, alanine, phenylalanine and tyrosine dominate by far. The total seed protein consists of significantly less of these four hydrophobic amino acids and contains more of the acidic amino acids. Three explanations are given which are supported by preliminary experimental results: 1. The vacuolar storage protein which is hydrolized during fermentation is enriched in these hydrophobic amino acids. 2. Free acidic amio acids are metabolized in the seed before onset of postmortem proteolysis. 3. Cocoa seed endopeptidases are aspartic acid proteinases. This type of enzyme gives rise to peptides with hydrophobic amino acids in the terminal positions which are the first to be attacked by exopeptidases.