Effect of Heat Curing of Film-forming Solution on the Properties of Soy Protein Films
Tasmia Bari
Department of Food Engineering and Technology, State University of Bangladesh, Dhaka, Bangladesh.
Md. Monirujjaman
Department of Food Engineering and Technology, State University of Bangladesh, Dhaka, Bangladesh.
Farzana Akter
Department of Nutrition and Food Engineering, Daffodil International University, Dhaka, Bangladesh.
Md. Shahriar Alam
Department of Food Engineering and Technology, Hajee Mohammad Danesh Science and Technology University, Dinajpur–5200, Bangladesh.
*Author to whom correspondence should be addressed.
Abstract
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.
Keywords: Biodegradable film, film-forming solution, heat curing, soy protein film, tensile strength