Fabrication and physicochemical characterization of HPMC films with commercial plant extract: Influence of light and film composition

Betacyanins used as natural red color (NRC) are known as antioxidants. The present paper was focused on their effect on physicochemical properties of hydroxypropyl methylcellulose (HPMC) films. All the films were evaluated for their photo-aging stability on optical, mechanical, barrier, thermal and structural properties. Both, tensile strength and Young's modules of NRC composite films decreased, while elongation significantly increased compared to control films. Dynamic vapor sorption data fitted by Guggenheim-Anderson-de Boer (GAB) model showed lower values of sorption energy for NRC composite films. NRC films showed an initial decrease in oxygen permeability that was more decreased after 20 days of photo-aging. Inversely, a significant increase in water vapor permeability of films by increasing NRC was observed. The films composed of 4% NRC (v/v) showed the highest WVP and lowest oxygen permeability. HPMC films transparency decreased with NRC contents. (C) 2012 Elsevier Ltd. All rights reserved.