Insight into the formation mechanism of soy protein isolate films improved by cellulose nanocrystals

This study aimed to evaluate the effects of cellulose nanocrystals (CNC) on the basic properties of soy protein isolate films, and especially to propose the corresponding formation mechanism. Tensile strength, barrier properties, and water resistance were effectively improved after the formation of nanocomposite films. Incorporating CNC could restrict water mobility and improve the viscoelastic properties of films. Appropriate content of CNC (0.50% and 0.75%) promoted the construction of a more homogeneous and compact film structure, which may be attributed to the CNC-induced conformational modifications and the enhanced hydrophobic and hydrogen-bond interactions. While excessive CNC (1.00%) was not conducive to the integrity and continuity of film structures, resulting in the weakened functional properties. The obtained films were able to decrease total viable counts and total volatile basic nitrogen of stored pork, and extend the shelf-life of strawberry. This work offers a theoretical basis for the application of CNC in packaging industry.