Enhancing yogurt quality with a high-EPS-producing space mutant Lactiplantibacillus plantarum LP-Wang25: integrated assessment of yogurt rheological behavior, flavoromics, and functional activities

Abstract

Exopolysaccharides (EPS) can serve as thickeners, emulsifiers, and gelling agents, and have been widely applied in the food industry. In situ production of EPS by lactic acid bacteria has emerged as a promising alternative to the addition of exogenous EPS, aligning with the growing demand for clean-label foods. The application potential of a space mutant of Lactiplantibacillus plantarum , designated LP-Wang25, as the adjunct starter culture was comprehensively examined via EPS quantification, carbon source utilization assays, whole-genome sequencing, antioxidant and anti-inflammatory activity assays, yogurt fermentation trials, sensory evaluation, and volatile flavor analysis. LP-Wang25 exhibited a shortened lag phase, 39.7% higher EPS production (161.95 mg/L), and enhanced antioxidant and anti-inflammatory activities compared with the parental strain. Whole-genome sequencing showed that EPS biosynthesis mainly proceeds through a conserved Wzx/Wzy-dependent pathway, indicating the increased EPS production is likely associated with transcriptional regulation and metabolic flux redistribution. When used as an adjunct starter, LP-Wang25 significantly improved yogurt quality by increasing EPS content and viscosity, reducing whey separation, enhancing milky aroma, acetoin concentration and sensory acceptability. LP-Wang25 represents a promising adjunct culture for producing clean-label yogurt with improved rheological and sensory attributes as well as enhanced antioxidant and anti-inflammatory activities. This study bridges space-induced microbial breeding with tangible dairy industry applications, paving the way for next-generation functional fermented products.