The quality and flavor profile of fermented milk produced by ABT-T is influenced by the gene in the quorum sensing system.

The /AI-2 quorum sensing (QS) system of regulates strain acid tolerance, yet its impact on milk fermentation remains unclear. This study aimed to elucidate the mechanism of and gene overexpression in the /AI-2 system of ABT-T on fermented milk quality using metabolomics. Results showed that gene overexpression had a greater impact on milk quality than the wild-type strain or gene overexpression strain. Overexpression of the gene significantly enhanced AI-2 secretion, reducing fermented milk pH, increasing acidity, improving fermented milk protein hydrolysis, and altering texture and water-holding capacity. Nineteen volatile flavor compounds were identified, with decreased ketone compounds due to the gene overexpression. KEGG analysis suggested significant alterations in amino acid metabolism pathways due to the gene overexpression. This study provides insights into the role of QS in fermented foods.