Tea processing shapes the structural characteristics and gut microbiota-modulating potential of polysaccharides from the fresh summer tea.

In this study, fresh summer tea leaves from the same cultivar and batch were processed into green, black, and dark (post-fermented) teas, and the corresponding polysaccharides (GTP, BTP, DTP) were subsequently extracted. Their digestive stability and gut microbial fermentability were evaluated. Simulated digestion of polysaccharides showed their strong resistance to enzymatic hydrolysis. In vitro anaerobic fermentation demonstrated GTP, BTP, and DTP could be effectively utilized by gut microbiota, resulting in increased production of short-chain fatty acids (SCFAs). Microbial analysis revealed that GTP exerted the strongest inhibitory effect on Escherichia-Shigella, while BTP most effectively suppressed Allobaculum. GTP significantly promoted the growth of Lactobacillus, BTP enriched Bifidobacterium, and DTP favored the proliferation of Bacteroides species. Furthermore, cultivation experiments confirmed that BTP significantly promoted the growth of Bifidobacterium. These findings collectively demonstrate that tea processing methods play a critical role in shaping the structural characteristics and prebiotic potential of polysaccharides.