Physicochemical and biological properties of carboxymethyl cellulose/locust bean gum composite films reinforced with nano- or microfibrillated cellulose loaded with essential oil

Recent studies have proposed the incorporation of different reinforcing materials into biopolymer films to improve their properties. In this study, carboxymethyl cellulose/locust bean gum composite films reinforced with nanofibrillated (NFC) or microfibrillated (MFC) cellulose loaded with oregano essential oil (OEO) were analyzed in terms of physical properties, microstructure, and molecular interactions, using FTIR, RXD, TGA, and DSC. Reinforced composite films (RCF) presented a significant (p ≤ 0.05) increase in thickness compared to the control, while RCF loaded with OEO did not modify their WVP (ranging from 91.73 to 120.18 g/m²/day). FTIR spectra indicated intermolecular interactions between NFC or MFC and other film constituents, and a distinct pattern of interactions was observed in RCF loaded with OEO, evidenced by alterations in peaks at 1580 and 1420 cm^-1. RCF with NFC or MFC presented similar OEO release behavior. RCF loaded with OEO completely inhibited fungal growth and spore germination of F oxysporum f. sp. lycopersici (Fol), and no phytotoxic effects were observed when used to coat tomato seeds. These findings highlight the potential of RCF as sustainable seed treatment alternatives due to their ability to stabilize OEO, ensure controlled release, inhibit fungal growth, and prevent phytotoxic effects.