Study of the Barrier and Mechanical Properties of Packaging Edible Films Fabricated with Hydroxypropyl Methylcellulose (HPMC) Combined with Electro-Activated Whey

Abstract

The aim of this work was to study the effect of composition and aging time on the physico-chemical, light barrier and color properties, water vapor permeability, mechanical and thermal properties of biodegradable packaging films made of hydroxypropyl methylcellulose (HPMC) incorporated with glycerol (G), non-electro-activated whey (NW) and electro-activated whey (EAW). The films were prepared from the solutions at pH 7 by pouring 6 g of each in the petri-dishes. These films were then stored for aging in a pre-conditioned experimental chamber at 23 ± 0.5 °C and 50% relative humidity (RH) during 30 days. All the films containing G, NW and EAW showed significant increase in film thickness and increase in moisture content (MC) as function of composition. The control film had a thickness of 49.00 ± 7.28 μm and the addition of 1% of whey and electro-activated whey did not decrease the film thickness which had the values of 42.86 ± 9.99 and 42.14 ± 5.24 μm, respectively. Addition of 2, 3 and 4% both whey and electro-activated whey induced significant increase of the film thickness to a maximum value of ≈ 85 μm. The significant increase in MC affected the mechanical properties causing a significant increase in color change (ΔE) values and a decrease in both tensile strength (TS) and Young modulus (YM). The water barrier properties were also affected due to this increase in moisture content (MC). After aging under controlled conditions, the MC of the films containing G, NW and EAW was constant which gave no change in the films properties. Scanning electron microscopy (SEM) images revealed significant microstructural differences between the control HPMC films and those incorporated with G, NW and EAW.