Ultrasonic-assisted enzymatic extraction, physicochemical properties and prebiotic activities of polysaccharides from Saccharomyces cerevisiae spore wall

Yeast wall polysaccharides (YWPs) are a bioactive compound found in the vegetative cells of Saccharomyces cerevisiae, contributing to its applications in food and medicine. YWPs have been extensively studied because of their diverse biological activities. Although the yeast spore wall of S. cerevisiae also contains polysaccharides, the biological activities of the components of the spores have received limited attention. In this study, yeast spore wall polysaccharides (YSWPs) were extracted from chs3Δ spores with exposed β-glucan layers via an ultrasonic-assisted enzymatic extraction (UAE) method, and the optimal extraction process was determined through single-factor and orthogonal experiments. The physicochemical properties of YWPs and YSWPs were compared under identical extraction conditions, and the effects of YSWPs on the abundance of the intestinal microflora and short-chain fatty acids (SCFAs) production in vitro were investigated. The results revealed that the optimal UAE process for YSWPs involves an ultrasonic power of 300 W, an ultrasonic duration of 60 min, an enzyme concentration of 1 % (w/w), and an enzymatic hydrolysis time of 4 h. The total sugar content of the extract was found to be 89.20 ± 0.52 %. The primary monosaccharides present in YSWPs are mannose and glucose, which are consistent with those found in the vegetative cell wall polysaccharides. Both YWPs and YSWPs exhibit similar physical properties, however, YSWPs has a smaller particle size, resulting in superior water-holding and oil-holding capacities. In simulations of in vitro colon fermentation, YSWPs can increased the population of beneficial microorganisms in the human intestine while reducing the number of harmful microbial populations. Additionally, it can effectively produced propionate and butyrate. These findings suggest that YSWPs can help maintain the intestinal ecological balance and promote intestinal health.