Enhanced off-flavor compounds biotransformation by microbial interaction between Saccharomyces cerevisiae and Lactobacillus plantarum assisted by physical excitor and yeast quorum sensing

Abstract

This study explored the mutualistic effects of yeast and Lactobacillus co-culture fermentation on degrading off-flavor compounds in duck liver (DL) like trimethylamine (TMA), dimethylamine (DMA), and histamine (HA). Ultrasonication (US) stimuli were applied to adjust microbial interactions and assess their impact on off-flavor metabolism. Degradation rates of TMA, DMA, and HA in single-strain fermentations reached 33 %, 24 %, and 60 %, respectively. In contrast, co-culture fermentation improved these rates to 39 %, 39.7 %, and 75 %. After US pretreatment (40 kHz, 400 W, 30 min), degradation rates further increased to 56 %, 54.7 %, and 90 %, respectively. Non-targeted analysis revealed that co-culture fermentation achieved the highest off-flavor removal, as evidenced by increased esters and decreased aldehydes. Key metabolites, including phenylacetaldehyde, phenylethanol, and D-limonene, were linked to fermentation patterns. US also elevated phenylethanol levels, a yeast quorum sensing (QS) signaling molecule, suggesting that QS-mediated interactions influenced off-flavor compound degradation. Enhanced yeast QS signaling molecules (phenylethanol, tryptophan, tyrosol) contributed to further off-flavor metabolism in US-stimulated fermentation, improving TMA degradation by 18 %-53 %, DMA by 16 %-30 %, and HA by 17 %-53 %. These findings demonstrate that US enhances the biodegradation of fishy substances by modulating yeast-Lactobacillus interactions, offering new insights into biotransformation processes.