Release of papain incorporated in chitosan films reinforced with cellulose nanofibers

This research presents an active biodegradable packaging, where papain was incorporated into chitosan films reinforced with cellulose nanofibers (CNF). The objective of this study was to evaluate the properties of chitosan-film and CNF (0%, 4%, and 8%, w/w) incorporated with papain (0%, 2%, 6%, and 10%, w/w) and their release in the aqueous medium. Films were characterized by thickness, scanning electron microscopy, UV-Vis light transmission, X-ray diffraction, proteolytic activity, and kinetics of papain release. The papain impaired the dispersion of the CNF in the polymer matrix and increase crystallinity, however, the films show good transparency. The proteolytic activity of the films increased according to the concentration of papain. The CNF acted to control the release of papain. Films made with 2% papain and 4% CNF presented the lowest diffusion coefficient of the papain and may be used in packaging where the slow release of the active compound is required. Novelty impact statement This research presents an active biodegradable packaging, where papain was incorporated into chitosan films reinforced with cellulose nanofibers (CNF). The films developed showed good transparency and both the addition of CNF and papain resulted in increased crystallinity of chitosan films. The films with CNF presented the lowest diffusion coefficient of the papain and may be used in packaging where the slow release of the active compound is required.