Feeding Effect and Antioxidant Capacity of Fermentation Broths Based on Strain-Specific Utilization of Poria cocos Polysaccharide Derivatives.

This study investigated the prebiotic properties of the supernatant from gluconic acid-hydrolyzed alkali-soluble Poria cocos polysaccharide (s-GA-PCP). s-GA-PCP directly promoted the proliferation of Bifidobacterium and Lactobacillus strains. Among the s-GA-PCP-utilizing strains, strain L10 (Bifidobacterium pseudolongum) exhibited the broadest feeding capability, as its fermentation broth supported the growth of all six non-utilizing strains. Analyses revealed that L10 produced a more diverse oligosaccharide profile and accumulated higher levels of amino acid and peptide metabolites. Furthermore, all tested primary broths reduced ROS, with strain-specific effects on antioxidant enzymes in HepG2 cells. The broths from strains L10, LQ-GL, and L1 showed the most pronounced effects, significantly (p < 0.05) increasing superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities while decreasing malondialdehyde (MDA) content. Secondary fermentation with non-utilizing strains resulted in strain-pair-specific modulation of ROS scavenging capacity. Collectively, these findings indicate that s-GA-PCP exerts prebiotic effects through strain-specific feeding and that its functional outcomes not only depend on primary fermentation but are also dynamically regulated by sequential microbial metabolism. This study provides a scientific basis for screening and applying sequential fermentation strain combinations of P. cocos polysaccharides, thereby supporting precision prebiotic design.