Study of the Volatile Compounds and Amino Acid Profile in Bacillus Fermented Castor Oil Bean Condiment

Abstract

Bacillus subtilis was used as a monoculture starter for the production of three different fermented castor oil bean condiments: B 1 ( 0% NaCl/Lime), B 2 (2% NaCl), B 3 (3% Lime). The volatile components of the three samples were determined using Gas –Chromatography / Mass Spectrometry (GC-MS) while High Performance Liquid Chromatography (HPLC) was used in the study of the amino acid contents. A total of seventeen volatile constituents were identified in the fermented castor oil bean samples using GC-MS. The compounds identified were of various types: acids, esters, alcohols, furans, ketones and others. However, acids were found to be the dominant constituent group followed by esters. Results from the amino acid analysis shows the three fermented castor oil bean samples contained sufficient amount of amino acids. The essential amino acids were in the range of 42.22 – 54.17% for EAA 7 and 63.76 – 73.82% for EAA 10 of total Free Amino Acids with the most abundant being tryptophan, isoleucine and phenyalanine. Bitter taste was observed as the predominant taste followed by sweet taste and tasteless amino acids. MSG-like taste was slight with B 1 :1.624 µg/ml, B 2 : 1.069 µg/ml and B 3 : 0.881 µg/ml. It is suggested that the desirable taste of ogiri from castor oil bean is formed by interactions between the amino acid and volatile components analyzed in this study.