Physicochemical Properties and Food Born Peptide Bioactivities of Fermented Cocoa Beans

Abstract

This study examined the physicochemical properties and bioactive peptides of fermented cocoa beans from the Indonesian regions of West Java, Yogyakarta, East Java, and Bali. Samples were analyzed for fermentation index, pH, free amino acids, total phenolic content (TPC), fat, and protein content. After the fat and polyphenol were removed, the remaining material was separated according to its solubility. The molecular weights were then evaluated using SDS-PAGE. The ACE inhibitory activity was evaluated by the hippuryl-L-histidyl-leucine (HHL) assay, and the antioxidant activity was analyzed by the di-phenyl-picryl-hydrazine (DPPH) radical scavenging activity (DRSA) assay. All samples showed full fermentation (FI 1.0-1.6; pH 5.1-5.8) with various contents of TPC, fat, and protein. Free amino acid profiles from different regions were not significantly different. Identified protein fractions included albumin (21 kDa), globulin (31-45 kDa), prolamin (27 kDa), and glutelin (75-200 kDa). All fractions exhibited bioactivity, with albumin showing the strong antioxidant and ACE inhibitory effects. Albumin might act as an ACE inhibitory activity through competitive mechanisms, whereas other protein fractions might exert their effects through noncompetitive pathways. This study highlights the value of fermented cocoa for future product development.

Keywords: angiotensin-converting enzyme; antioxidant; cocoad bean; fermentation; peptides.