Optical and structural properties of biodegradable whey protein isolate nanocomposite films for active packaging

Abstract

Films of whey protein isolate/sodium montmorillonite/citric acid nanocomposites were developed by casting. The objective of this study was to evaluate the effect of the sodium montmorillonite clay (MMT) and citric acid (CA) content on the water vapor barrier, optical, morphological and structural properties of whey protein isolate (WPI) films. The interaction between MMT (3 g/100 g of WPI) and CA (5 g/100 g of WPI) showed lower water vapor permeability (WVP). The addition of CA and MMT caused small alterations in the optical properties without affecting appearance, in more opaque films, in relation to the WPI. The scanning electron microscopy (SEM) showed possible dispersion results for films with 1% MMT, and 5 and 10% CA. Infrared Spectroscopic peaks (FTIR) showed interaction between CA, MMT and WPI.