Analysis of Amino Acids in Cocoa Beans Produced during Fermentation by High Performence Liquid Chromatography (HPLC)

Abstract

Fermentation is a very vital stage of cocoa processing to obtain high quality chocolate product. This study was conducted to obtain an optimal result of chocolate fermentation by determining the concentration and types of amino acid of lindak clone cacao beans using HPLC. Pre-conditioned process was done in order to get water content to 15% in pulp the same level as the traditional process from farmer. Before fermentation dried cocoa beans were rehydrated to obtain a water content of pulp at the same level as fresh cocoa bean pulp. The fermentation, was conducted for 120 h. The fermentation the three level treatments an control without inoculum, mixed with culture of microbies add and the begining of fermentation. The fermentation was started using Saccharomyces cerevisiae, Lactobacillus lactis and Acetobacter aceti was added the fermentation and finally, treatment gradually microbies added during fermentation. The analysis of amino acids was conducted using HPLC separation method based on the procedure at outlined earlier. The measurement of amino acid was performed in two phases, liquid hydrolysis, and derivatization proceeded by chromatographic analysis. Condition of HPLC was measured at 37°C. Mobile phase contains of 60% acetonitril-AccqTag Eluent A, gradient system and the flow rate was 1.0 ml per minute. Fluorescence detector had 250 nm excitation and 395 nm emission. Injecting volume was 5 uL. The results of this study showed that cocoa beans 120 h fermentation has higher products of aspartic acid, glutamic acid, hydrophobic amino acids (Alanine, leucine, proline, valine, isoleucine) and amino acids such as serine, glysine, histidine, treonine and lysine, while local clones of cocoa beans with 3-days fermentation produce more amino acids such as aspartic, glutamic, hydrophobic (isoleucine, leucine, valine) and amino acids such as histidine, threonine, glysine, serine and lysine.