Digestibility of squash polysaccharide under simulated salivary, gastric and intestinal conditions and its impact on short-chain fatty acid production in type-2 diabetic rats.

In vitro digestive conditions were simulated to investigate the digestibility of polysaccharides prepared from squash (SPS). A small amount of free glucose monosaccharide was released after salivary and intestinal digestion due to the breakdown of α-(1 → 4)-glucose linkages and may form SPS or a starch impurity. At the same time, there was no obvious change in molecular weight distribution and reducing sugar content throughout this digestion period, demonstrating that the main structure of SPS was relatively stable under the simulated digestive conditions. Thus, most SPS can be transported intact to the large intestine. In addition, SPS alleviated type 2 diabetes (T2D) in rats. Moreover, the content of short-chain fatty acids (SCFAs) in the colon significantly increased after treatment with SPS. The present research provides insight into the non-digestibility of SPS, and suggests its utility to alleviate T2D by promoting the production of SCFA in the colon.