Comparative Study on the In Vitro Fermentation Characteristics of Three Plant-Derived Polysaccharides with Different Structural Compositions

This study aimed to elucidate the structure–activity relationship between the structural characteristics of three plant-derived polysaccharides, Lycium barbarum polysaccharide (LBP), citrus pectin (CP) and peach gum polysaccharide (PGP), and their prebiotic functionalities. Structural analysis indicated that LBP exhibited a medium molecular weight and was rich in galactose and rhamnose, which contributed to its high uronic acid content, strong antioxidant activity, and sustained fermentation profile with enhanced butyrate production. In contrast, CP, with its low molecular weight and neutral linear glucan backbone, was rapidly utilized by gut microbiota, leading to accelerated propionate accumulation. Meanwhile, PGP, characterized by an ultra-high molecular weight and a highly branched arabinogalactan configuration, acted as a specific substrate that promoted mid- to late-stage fermentation and significantly increased butyrate yield, highlighting its prebiotic property driven by structural complexity. The functional differences among these polysaccharides were determined by their monosaccharide composition, molecular weight distribution, and chain conformation. These findings provide a scientific basis for the targeted development of plant-derived prebiotics aimed at specific metabolic functions.