Rapeseed Protein-Based\nBioplastic Nanocomposite Films\nContaining Cellulose Nanocrystals, Montmorillonite, and Hydroxyapatite\nfor Food Packaging

Rapeseed protein-based nanocomposite films were developed\nthrough\na compression molding process, incorporating cellulose nanocrystals\n(CNC), surface-modified montmorillonite (MMT), and hydroxyapatite\n(HA) as nanofillers. The primary aim of this study was to enhance\nthe properties of the bioplastic films, specifically focusing on potential\napplications in food packaging. The results demonstrated that bioplastic\nfilms containing 3% nanofillers exhibit superior properties compared\nto the control film. The improved characteristics of nanocomposite\nfilms based on rapeseed proteins are attributed to the synergistic\ninteractions between the nanofillers and the protein matrix. Notably,\nCNC displayed optimal mechanical properties, with a tensile strength\nof 7.2 ± 2 MPa and a percent elongation of 128 ± 4%. In\ncontrast, HA had a less pronounced effect, yielding values of 5.6\n± 1.3 MPa and 149 ± 9%, respectively. Similarly, MMT had\na comparatively weaker impact, resulting in values of 4.4 ± 1.2\nMPa and 44 ± 5%. The influence of storage at 25 °C on the\nstability of the films was also examined. Prolonged storage under\nuncontrolled conditions accelerated the aging process of the films\nprimarily due to plasticizer migration and moisture loss. These changes\nnot only affected the films’ characteristics but also induced\nchanges in their secondary structure and arrangement. Conversely,\nthe incorporation of nanofillers enhanced film stability, mitigating\nplasticizer migration and thereby slowing the aging process. Overall,\nthe findings suggest that compression-molded rapeseed protein-cellulose\nnanocrystal nanocomposite (RP-CNC) is well suited for packaging applications,\nmaintaining stability for up to 4 weeks of storage under room-temperature\nconditions.