Effect of the maturation process on fermented cocoa bean I: free amino acids and volatile carbonyls

The maturation step in cocoa processing was originally introduced to reduce acidity of the cocoa bean. This study shows that maturation causes a decrease in free amino acids except glutamic and aspartic acid. Maturation also showed an increase in volatile carbonyls. The main increases were in diacetyl, formaldehyde, acetone, acetaldehyde. butyraldehyde (normal plus iso-) and valeraldehyde ( normal plus iso-) levels. Although there appears to be a relationship between these two trends, the appearance of carbonyls appears to be caused not only by degradation of amino acids but also other processes for example the oxidative degradation of fatty acids. Roasting caused a further decline of amino acids and increase of carbonyls presumably due to the Strecker reaction.