Chitosan-nanocomposites as a food active packaging: effect of addition of tocopherol and modified montmorillonite

Abstract

The development of natural biodegradable polymers to partially or totally replace synthetic polymers may be advantageous in food packaging, mainly when are associated with additional features such as active packaging. This article aimed to evaluate the effect of tocopherol concentration (0, 5, 10, and 20%) and modified montmorillonite clay (MMT15A) nanoparticles (0 and 1%) on the properties of chitosan (CS) films. The addition of tocopherol provided antioxidant activity and improved the thermal stability of the films, and acted as a plasticizer, decreasing the tensile strength, elastic modulus, and glass transition temperature of the films. Although MMT15A and tocopherol did not change the water vapor permeability, an improvement of the mechanical strength and lower equilibrium moisture content was observed when compared to the treatment made with CS alone. Both MMT15A and tocopherol allowed the production of bio-nanocomposites with thermal, morphological, mechanical, and water-resistant properties to be used as an antioxidant in packaging materials.

Practical Applications The films containing both montmorillonite (MMT15A) and tocopherol presented an improved mechanical strength, thermal stability, and antioxidant activity when compared to the films containing the only tocopherol. Therefore, it was possible to develop antioxidant chitosan films with improved properties using up to 20% tocopherol and MMT15A. At this tocopherol and MMT 15A concentrations, the films may also be used to nutritionally enrich food, adding value to the package and the conditioned product. Furthermore, the films can also be considered edible films with combined properties.