Jiangshui-derived lactic acid bacteria with high hypoglycemic potential: functional properties and fermentation performance of Sonchus oleraceus Jiangshui

This study investigated the probiotic properties of Lactobacillus paracasei (LAB 815) isolated from Gansu Jiangshui and Saccharomyces cerevisiae (SC 8(3)), along with their functional activities and fermentation performances in Sonchus oleraceus L. ( S. oleraceus ) Jiangshui . Both LAB (815) and SC 8(3) had good gastrointestinal tolerance and auto-aggregation ability, and neither strain showed hemolytic activity. The functional activity assays showed that the fermented S. oleraceus Jiangshui (F2) produced through co-fermentation with LAB 815 and SC 8(3) exhibited superior biological activities, including α -glucosidase and α-amylase inhibitory effects, ACE inhibitory activity, strong antioxidant capacity, and significant antimicrobial activity against pathogenic bacteria. The results of simulated gastrointestinal fluid test showed that the inhibition rates of α -glucosidase, α-amylase and ACE decreased in all groups (F1, F2, F3 and F4), indicating a partial loss of these enzyme inhibitory activities after gastrointestinal transit. However, the F2 group maintained relatively higher activity compared to the other groups and maintained inhibition rates of approximately 50%. The fermentation performance results showed that the F2 produced acid more rapidly and achieved a greater pH reduction compared to other groups (F1, F3, F4). Metabolite analysis showed that F2 resulted in a significant increase in the major metabolites such as amino acids (+339.954 mg/100 mL), alcohols (+29.118%), esters (+25.295%) and organic acids (+15.12%). The sensory evaluation results showed that the overall acceptability of the S. oleraceus Jiangshui was significantly improved. The present findings could confirm the key role of co-fermentation of LAB 815 and SC 8(3) in improving the taste quality and potential health functions of S. oleraceus Jiangshui .