Digestive Property and Bioactivity of Blackberry Polysaccharides with Different Molecular Weights

In the present study, the digestion and fermentation of blackberry polysaccharides (BBPs) with different molecular weights (Mw) were investigated. The results showed that the Mw decrease rates of BBP, BBP-8, BBP-16, and BBP-24 were 77.48, 69.61, 56.87, and 52.89%, respectively. The antioxidant and α-glucosidase inhibitory activities of BBPs were decreased under gastrointestinal condition, which might be due to the variation of Mw during digestion. The bile acid-binding ability of BBPs showed an Mw-dependent manner for higher Mw polysaccharides with higher viscosity. Through fermentation, the BBPs affected the ecosystem of the intestinal tract by promoting the production of short-chain fatty acids, lowering the pH of colon, and decreasing the ratio of Firmicutes to Bacteroidetes. All BBPs showed almost a similar modulation effect on the gut bacteria, but the lower Mw polysaccharide was more easily utilized by bacteria.