Abstract: To explore the mechanism of the sol-gel transition of gelatin (GL)/modified starch (MS) blends in glucose syrup (GS) cosolute system, the evolving trend of viscoelastic modulus (G’ and G”) and the transition kinetics were investigated by dynamic rheology. Based on the first and second order derivatives of G’ versus t curves, there existed four characteristic temperatures for sol-gel (Tig, Tg, Tcg and Tmg) and gel-sol (Tis, Tcs, Ts and Tms) transition either separately, correspondingly dividing the phase transition process into five stages. During the phase transition process, the existing state of gelatin molecules was determined by these characteristic temperatures. With the increase of GS concentration (0%–60%, m/m), the initial sol-gel phase transition temperature (Tig) and gel point temperature (Tg) were increased, and the gel strength of GL/MS blend was decreased significantly. However, there was a downward trend in the sol point temperature (Ts). The activation energy (Ea) value of the phase transition process in the high temperature zone were decreased firstly and then increased with the increase of GS concentration, while the Ea value in the low temperature zone was not changed significantly. These results could provide a theoretical basis for the process optimization and quality control of GL/MS blend gel products.

Key words: glucose syrup, gelatin/modified starch blend system, rheology, phase transition, kinetics