Effect of mulberry leaf polysaccharides on the physicochemical, rheological, microstructure properties and in vitro starch digestibility of wheat starch during the freeze-thaw cycles

Abstract

Temperature fluctuation damages the quality of starch-based foods, and the freeze-thaw cycle (FTC) can simulate this process. This study investigated how Mulberry leaf polysaccharides (MLP) affect the freeze-thaw stability and digestibility of wheat starch (WS). During FTC, MLP reduced the syneresis and retarded the water migration of WS gel. Meanwhile, MLP delayed the recrystallization of starch, which reduced the enthalpy value and crystallinity of WS gel during FTC. The addition of MLP significantly reduced the hardness of WS gel. Furthermore, MLP could prevent the deterioration of the rheological characteristic and preserve the network structure of the WS gel. In addition, MLP boosted the resistant starch and decreased the fast-digesting starch content in the freeze-thaw gel. Our findings suggested that MLP could enhance the freeze-thaw stability of WS gel, decrease the starch digestibility, and be an effective component in improving the quality of wheat starch-based frozen food.