Calcium ion-enhanced physically double-crosslinked starch-sodium alginate hydrogels: A sustainable approach for improving the quality of thermally sterilized rice noodles.

Thermal sterilization is an economical and eco-friendly method for extending the shelf-life of fresh rice noodles (RN). However, this process often leads to deterioration in extensibility and quality, adversely affecting both mechanical properties and eating quality. The aim of this study was to construct a dual physically cross-linked starch hydrogel using starch, sodium alginate (SA), and calcium chloride (CaCl2) to mitigate these issues. The physicochemical and structural properties of RN were characterized using texture analysis, contact angle measurements, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The addition of 1.33 % SA resulted in a 1.20-fold increase in tensile strain, a 41.89 % reduction in cook breakage rate, and a 0.76-fold decrease in cooking loss rate compared to the control. Hydrophilicity was enhanced by 13.57-43.65 %. SEM analysis revealed that the hydrogel network became denser, more uniform, and more organized. This study provides valuable insights for the development of green, high-quality, thermally sterilized rice noodles.