Fabrication of antioxidative food packaging films using cellulose nanofibers, kappa‐Carrageenan, and gallic acid

Abstract

Kappa-Carrageenan (KC) and cellulose nanofibers (CNF) were successfully grafted with gallic acid yielding modified polymer films with antioxidant capacity. Modification of KC and CNF was performed via two different routes: a radical method and an acylation method. Grafted polymers were analyzed for evidence of grafting, antioxidant capacity, phenolic content, and color change. Composite films were fabricated using the modified and unmodified KC and CNF, and their corresponding mechanical properties were investigated. Both routes resulted in gallic acid being grafted onto the polymers. Maximum antioxidant activity (85% DPPH inhibition) and total phenolic content (TPC) (0.06 mg GAE/mg sample) were observed for radical grafted CNF and depending on the grafting route used, color was affected. Superior mechanical property (99 ± 7 MPa; tensile strength) greater than CNF was observed with radical grafted CNF. Modification of polymers KC and CNF and subsequent composite film formation can yield films with potential use in food industry. Practical applications In this research, antioxidant moieties, such as gallic acid, were grafted onto biodegradable and renewable polymer such as Cellulose Nanofibers and Kappa-Carrageenan making it antioxidant. Such antioxidant biodegradable polymers, when formed into packaging films, have the capacity to increase the shelf life of high-fat food, thereby reducing food waste and combating plastic pollution.