Cross-linked Arenga pinnata (Wurmb.) Merr. starch and chitosan with sodium trimetaphosphate: Structure, physicochemical properties and in vitro digestibility.

The inherent limitations of native starch considerably restrict its applications in the food industry. To enhance its processing properties, Arenga pinnata (Wurmb.) Merr. starch (APS) was subjected to dual modification with low levels of sodium trimetaphosphate (0%, 1%, and 3%) and chitosan (1%) to investigate its physicochemical, thermal, pasting, and in vitro digestibility. The dual modification of APS significantly increased the degree of cross-linked (CLD) to 84.69%, resulting in a rougher surface texture. This process led to the formation of phosphate bonds, the weakening of hydrogen bonds, and a decrease in relative crystallinity, all while preserving the starch's crystalline structure. Additionally, the modification impeded paste formation, reduced swelling power, and lowered pasting enthalpy, while increasing the content of slowly digestible starch and resistant starch. These findings provided a basis to enhance the functional properties of starch-based materials, which could be applied to improve the texture and stability of food products such as sauces, dressings, and desserts in the food industry.