Colonic fermentation of longan pulp polysaccharides extracted with various pretreatments and their facilitation to Lactobacillus adhesion properties

Longan polysaccharides (LP) have been demonstrated to possess various health benefits related to gut microbial modulation. Herein, the effects of superfine grinding and enzymolysis pretreatments on the colonic fermentation characteristics of hydrothermal-extracted LP were investigated. LP extracted with combined superfine grinding and enzymolysis pretreatment (LP-SE) exhibited a greater degree of degradation (85.82%) than the untreated polysaccharides (LP-H) during fermentation. The enhanced degradation of LP-SE relative to LP-H was primarily attributed to a shift in molecular weight distribution toward a lower range (2.38-667.8 kDa) and a simpler glycosidic linkage composition, rather than to changes in the proportions of the major monosaccharides, including arabinose and galacturonic acid. The enrichment of Bifidobacterium , Desulfovibrio , and Lactobacillus during LP fermentation highlighted their involvement in polysaccharide metabolism and synthesis of short-chain fatty acids. Notably, LP fermentation products significantly promoted mucin-adhesion properties of representative Lactobacillus strains by upregulating mucBP expressions, particularly for LP-SE. These findings indicate that combined superfine grinding and enzymolysis serves as a potential strategy for enhancing polysaccharide bioactivities. Download: Download high-res image (433KB) Download: Download full-size image