Mesona chinensis polysaccharides promote molecular crosslinking and gel formation of debranched waxy maize starch

Abstract

The effect of Mesona chinensis polysaccharides (MCP) on the gel, rheological, and structural properties of debranched waxy maize starch (DWMS) were investigated. The gel strength of DWMS-MCP gels first increased and then decreased with MCP concentrations. Addition of MCP (≤1 g/100 g) revealed higher dynamic modulus with a more solid-like behavior. However, an excess of MCP had the opposite effect. Inverted fluorescence microscopy showed that the network-like structure of DWMS became firmer and denser with addition of 0.5 and 1 g/100 g MCP, whereas it became weaker and more scattered at higher MCP concentrations. Fourier transform infrared spectroscopy and X-ray diffraction analysis showed that the appropriate amount of MCP (0.5 and 1 g/100 g of DWMS) could significantly increase the values of 1047 cm−1/1022 cm−1 and relative crystallinity, suggesting that the DWMS recrystallization was accelerated by MCP. Low-field nuclear magnetic resonance showed that a stronger gel network led to more strongly bound water. The effect of MCP on performance of DWMS gel mainly through the interaction with DWMS or the phase separation with DWMS at high MCP concentrations. Based on these measured results, a potential mechanism for the impacts of MCP on DWMS gel was proposed.