Structural characterization and prebiotic activity of a novel polysaccharide from rice bran

The chemical structure and prebiotic activity of a novel rice bran polysaccharide (RBP) were elucidated in this study. RBP was determined to be a typical heteropolysaccharide composed of arabinose (6.95%), galacturonic acid (2.13%), glucose (82.93%), galactose (5.15%), xylose (2.07%), and glucuronic acid (0.78%). DSC, TG, and XRD indicated RBP to be thermally stable and predominantly in an amorphous form. Results from methylation analysis and NMR spectroscopy suggested the main backbone of RBP to be predominantly →4)-α-D-Glc p -(1→, and →4,6)-α-D-Glc p -(1→. Fecal fermentation experiments demonstrated that RBP promoted the production of short-chain fatty acids, facilitated the propagation of beneficial bacteria ( Bifidobacterium and Lactobacillus ), and suppressed the proliferation of harmful bacteria ( Fusobacterium ) and pathogens ( Escherichia-Shigella ), thereby exerting probiotic effects. This study comprehensively analyzed the structure and probiotic activity of RBP and highlights its potential as a functional food.