Mechanical properties and water sensitivity of soybean protein isolate film
The effects of incorporation of sodium caseinate and transglutaminase treatment on the properties of film-forming solutions and their resultant films were systematically studied, changes in the former explaining improved properties of the latter. Increases in protein molecular weight, particle size, and viscosity, and decreases in lysine residue content of the solutions confirmed the formation of new macromolecular proteins following transglutaminase cross-linking.
Improved critical properties
Increased hydrophobicity of proteins revealed the reason for decreases in water sensitivity of the films. The tensile strength and the hydrophobicity of the films significantly increased, while water solubility, water vapor permeability and elongation at break decreased by 37 %, 32 % and 71 %, respectively, in the presence of sodium caseinate and transglutaminase.
In general, the coexistence of sodium caseinate and transglutaminase treatment significantly improve critical properties of soybean protein isolate-based films, particularly water sensitivity and tensile strength, and expand their potential applications in humid environments.
The study has been published in Progress in Organic Coatings, Volume 153, April 2021.