Effects of two-step heating process on hydrophobicity and barrier properties of protein-based composites

Abstract

Objective: To improve the film heating process. Methods: In this experiment, edible protein-polysaccharide films were prepared by using the method of chain dissociation at 35, 40, 45, 50, 55 ℃ at one stage and denaturing and heating whey protein isolation at 85 ℃ at the second stage. The structure, hydrophobicity, barrier properties and mechanical properties of the films were compared, and the optimum film forming process conditions were determined. Results: The oxygen resistance, tensile strength （TS） and elongation at break （EAB） of the film increased by 25.0%~58.7%, 54.8%~89.9% and 40.2%~59.2%, respectively, when the film was heated at 25 ℃ and 85 ℃ respectively. Water vapor barrier performance improved by 20.0%~52.6%. The infrared map of the film shows that temperature does not cause the change of the valence bond of the film. It was found that 45 ℃/85 ℃ two-stage step heating process had the most significant effect on improving the properties of the film. Conclusion: After the process optimization, the film's barrier properties and mechanical properties have been improved, which has the potential for food packaging applications.

Keywords

• two steps heating film
• whey protein isolate
• structural change
• hydrophobicity
• barrier property