Antioxidant and antimicrobial modified cellulose nanofibers for food applications

Abstract Cellulose nanofibers (CNF) are renewable, biodegradable, and non-toxic biopolymers; however, they have not been widely adopted as an additive by the food industry. In this study, CNF functionality was improved through chemical modification. Antioxidant and antimicrobial nanofibers were produced through the esterification of CNF with phenolic acids. CNF were esterified with vanillic or cinnamic acid using two different esterifying agents: thionyl chloride and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Modified fibers from the four different treatments were evaluated for their structural properties, antioxidant properties, thermal stability, dispersibility and antimicrobial properties. Both esterifying agents successfully produced phenolic acid esterified CNF fibers. Vanillic acid modified fibers showed better antioxidant activity (70% DPPH radical scavenging activity) than cinnamic acid modified fibers (10% DPPH scavenging activity). In contrast, cinnamic acid modified fibers showed better antimicrobial activity against Staphylococcus epidermidis. Thermal stability depended on the esterifying agent utilized; the use of thionyl chloride (DTG max 260.19 ± 1.38 °C) significantly (p