Effect of sucrose and sorbitol on properties of protein based-film from red tilapia (Oreochromis niloticus) fish

During the last decade, there has been growing interest in edible or biodegradable films based on biopolymers. Edible films and coatings are of interest since they have potential to improve shelf-life, maintain quality and prevent microbial deterioration and physical damage of foods. In this research, edible films based on red tilapia (Oreochromis niloticus) protein in the presence of cryoprotectants of sucrose and sorbitol at different levels (4%sucrose, 4%sorbitol, 2%sucrose+2%sorbitol, 4%sucrose+4%sorbitol) were prepared by casting method using glycerol as plasticiser. Films containing cryoprotectants, except for 4% sucrose, had lower tensile strength (TS) accompanied with higher elongation at break (EAB), compared with the control film (P < 0.05). However with increasing in cryoprotectant levels, Water vapour permeability (WVP), film and protein solubility significantly increased. Regarding color, whiteness increased and yellowness declined as the cryoprotectants levels increased. Also, film with cryoprotectants had a smoother and more homogeneous surface without cracks. Results show that cryoprotectants present in the fish mince or surimi due to the plasticizing effect, directly affected properties of films.