Identification of Volatile compounds from Pure Culture fermentation of African Oil Bean Seed using Lactobacillus fermentum and Bacillus subtilis

Abstract This study investigates the fermentation process of African oil bean seed ( Pentaclethra macrophylla ) into Ugba , focusing on the roles of Bacillus subtilis and Lactobacillus fermentum in flavour development. Fermentation is a traditional method that enhances food safety and quality, and Ugba is a culturally important condiment in Southeast Nigeria. The research employed a systematic approach, the interaction between boiling and soaking durations on microbial activity and the resultant compounds that are volatile produced during fermentation. Samples of the seeds of African oil beans were subjected to different boiling and soaking times before fermentation with both single and co-cultures of the selected microorganisms. The volatile components were examined using a gas chromatography-mass spectrometry; i.e. (GC-MS), revealing 24 distinct compounds, with co-culture fermentation yielding a more diverse profile compared to single cultures. Notably, 2-nonen-1-ol was identified in co-culture fermentation, indicating enhanced flavour complexity. In naturally fermented Ugba , 14 volatile compounds were produced with methyl stearate, n-hexadecanoic acid, methyl ester, and oleic acid being more consistent and predominant. However, Bacillus subtilis pure culture fermentation produced 27 volatile compounds with methyl stearate, methyl ester and n-hexadecanoic acids being more prominent while Lactobacillus fermentum fermentation produced 34 compounds with hexadecanoic acids, methyl esters, and 9- octadecanoic acids being more prominent. Co-culture fermentation produced 24 volatile compounds including 2-nonen-1-ol which was not prominent as found in single/pure form fermentation. The main flavour components may be Methyl esters of different long-chain fatty acids depending on their stability and consistency in both single-culture and co-culture fermentation. This research not only contributes to the understanding of Ugba fermentation but also presents opportunities for standardizing production processes to achieve consistent flavour profiles. The insights obtained from this study have potential applications in the food industry, particularly in enhancing the sensory attributes of fermented products and expanding their culinary uses.