Gelatinization, rheological and retrogradation behaviors of waxy rice starch affected by gelatin emulsion and regulation mechanism

The influences of various gelatin emulsion additions on gelatinization, rheology, retrogradation and structural properties of waxy rice starch (WRS) were investigated. The gelatin emulsion was uniformly dispersed in the starch pastes, which increased the particle size through agglomerating around the starch powder particles. As gelatin emulsion content increased, the pasting viscosity of WRS pastes significantly increased (P < 0.05), whereas its setback value, gelatinization and retrogradation enthalpy decreased. Rheological measurements indicated that the addition of gelatin emulsion did not change the shear thinning behavior of WRS pastes blends, and the storage modulus and loss modulus were positively correlated with gelatin emulsion content. During the heating stage of the pasting process, the interfacial organization consisting of gelatin undergoes disintegration and melting, reconfiguring the emulsion system. Gelatin dispersed in the interfacial and continuous phases interacts with starch to form hydrogen bonds and inhibit starch rearrangement. The starch-lipid complex formed by the interaction between lipids released from emulsion and starch is capable of destroying the crystalline region. Therefore, after 14 d of storage at 4 °C, the relative crystallinity of WRS decreased by 72.4 % as the gelatin emulsion addition was increased from 0 % to 14 %. The addition of gelatin emulsion induced the formation of steric hindrance effects, which impeded the mobility of water molecules and improved freeze-thaw stability. These results may contribute to the creation of high-quality and innovative water-oil-starch mixture food products that remain fresh for a longer period.