Reinforcing and release controlling effect of cellulose nanofiber in sodium caseinate films activated by nanoemulsified cinnamon essential oil

Abstract

Abstract In this study, sodium caseinate (SC) nanocomposite active films were prepared by the addition of 5% (w/w of SC) cinnamon essential oil nanoemulsion (CEO-NE), as active agent, and 2.5 and 5% (w/w of SC) cellulose nanofiber (CNF), as reinforcing additive. The morphological characteristics, tensile properties, water vapor permeability (WVP), moisture absorption, color properties, release profile and the antioxidant/antimicrobial activity of the films were studied. The X-ray diffraction (XRD) test confirmed the increase in the crystallinity of the films by the addition of CNF. Scanning electron microscopy (SEM) approved the reduction of porous structure in the presence of CNF. Both moisture absorption and WVP of the SC films decreased, while the mechanical properties were improved by the addition of CNF and CEO-NE. The transparency and yellowness index increased by the addition of CNF and CEO-NE. CNF exhibited release controlling effect on CEO. The films containing CEO-NE and 2.5% CNF showed the highest antioxidant activity (66.04%). The CEO-NE loaded films had weak antimicrobial activity against S.aureus, E.coli, S.enteritidis and P.aeroginosa. This research demonstrated that the SC film reinforced with CNF and activated by CEO-NE would be a suitable candidate for the shelf life extension of different perishable foods.