Mesona chinensis polysaccharide on the thermal, structural and digestibility properties of waxy and normal maize starches

The Mesona chinensis polysaccharide (MCP) was compounded with waxy maize starch (WS) and normal maize starch (NS) to obtain composite gels. The effects of MCP on the digestibility, the thermal and structural characteristics of WS and NS were determined by simulating gastrointestinal digestion, differential scanning calorimetry (DSC), particle size distribution analysis, low-field nuclear magnetic resonance (LF-NMR) and confocal laser scanning microscopy (CLSM). Results showed that MCP reduced the endothermic enthalpy, spin relaxation time, and migration of free water, but increased the gelatinization temperature, median diameter, and starch granule size of all starch-MCP gels. MCP also increased the content of the resistant starch of starch-MCP gels, especially for WS-MCP gels. The inhibitory effects of MCP on water activity, the coating effect on the starch granules, and the promotion of starch granule swelling and aggregation were responsible for the reduced starch digestibility.