Physicochemical characterization and enteroprotective activity of triple-helix Gleditsia seed polysaccharides prepared by the probiotic fermentation method

To address the scarcity of natural plant-derived triple-helix polysaccharides, Gleditsia seed polysaccharides (GSPs) with intestinal benefits have been used as raw materials. Fermentation converts naturally disordered polysaccharide structures into triple helices. We applied the Drosophila intestinal inflammation model to assess polysaccharide activity. After 3-h fermentation with Bacillus subtilis, triple-helix GSPs were prepared. GSP-f exhibited a 31.83 % higher yield and a 1.66-fold improved solubility compared to GSP-u, with an optimized molecular weight (1.48 × 10⁵ g/mol) and a 2: 1 mannose/galactose ratio. In Drosophila models, GSP-f showed 30.50 % enhanced intestinal epithelial protection, 13.17 % improved barrier repair, 19.97 % lifespan extension, and a 40.4 % elevated Firmicutes/Proteobacteria ratio compared with GSP-u. Correlation analysis revealed that the triple-helix structure was correlated with the Firmicutes abundance. Notably, GSP-f and GSP-f-2 exhibited equivalent bioactivity. The fermentation-produced triple-helix polysaccharides achieved optimal functionality without purification. These findings highlight the potential of probiotic fermentation for the efficient production of high-performance triple-helix polysaccharides.