Preparation and Properties Characterization of Rice Protein-Sodium Alginate IPN Hydrogel

In order to meet the demand of high mechanical strength hydrogels in the food field, broken rice protein and sodium alginate were used as the main raw materials to prepare a food-grade broken rice protein (RP)-sodium alginate (SA) interpenetrating polymer network (IPN) hydrogels with high mechanical properties through heat treatment and ion cross-linking in this study. The mechanical properties of IPN hydrogels were adjusted by changing the concentration of rice protein (80, 100, 120, 140, 160 mg/mL) in the gel system of rice protein and sodium alginate, and the properties of the hydrogels, such as texture, rheological properties, whiteness, swelling and water content, were measured after the mixture was heated and Ca²⁺ cross linked. The results showed that: With the increase of the concentration of broken rice protein in the gel system, the storage modulus G', loss modulus G" and gel hardness of RP-SA IPN hydrogels increased. When the broken rice protein concentration was 140 mg/mL, the increase of gel hardness became smaller. The swelling property of hydrogels first decreased and then tended to be flat, but the water distribution was more uniform. Therefore, proper amount of broken rice protein could fill the RP-SA IPN hydrogels network very well, and the morphology of the hydrogel was not changed greatly. At the same time, the mechanical properties of hydrogels could be regulated by regulating the amount of protein added. This study provides a theoretical basis for the application of rice protein in the field of food.