Effect of Heat Curing of Film-forming Solution on the Properties of Soy Protein Films

This study aimed to investigate the impact of heat treatment on the properties of soy protein isolate film-forming solutions. The solutions, consisting of soy protein isolate, glycerol, and phosphate buffer solution (pH 7.4), were subjected to heat treatment at 65, 75, and 85°C for 2, 4, or 6 h. The resulting films were then analyzed for tensile strength, elongation at break, film solubility, color parameters, and transparency. The results indicated that increasing the heat-curing temperature increased tensile strength, film transparency, and yellowish color in the films, as well as decreased water solubility and elongation at break. Notably, the film cured at 85°C for 2 h exhibited the highest tensile strength, film solubility, and elongation at break compared to both the control and other heat-cured films. However, the film heated at 75°C showed a better elongation at break. Overall, the findings suggest that heat curing of film-forming solutions at temperatures between 75 and 85°C has the potential to improve the properties of soy protein isolate films.