Water Vapor Permeability of Edible Films Based on Whey Protein Concentrate and Olive Oil

In this study, water vapor permeability (WVP) of edible films made of whey protein concentrate was investigated. Whey protein films were prepared by dispersing 10% whey protein in distilled water; and plasticized with different levels of glycerol (Gly) (glycerol: protein (Gly: Pr) =0.5 and 0.6). Olive oil was added at different levels (Oil: pro= 0.0, 0.2, and 0.4). The emulsion films were evaluated for mechanical properties, water vapor permeability and opacity.Increasing the levels of Gly or olive oil in the films led to decreases in Elastic Modulus (EM) and Tensile Strength (TS). Increasing Gly content of films at oil/pro ratios of 0.2, 0.4 led to slight increases in Elongation (EL). Increasing the oil: pro ratio further resulted in a decrease in Elongation (EL) for all films. No significant difference in WVP and Opacity was observed between films made from mixtures of various proportions Of WPC-Gly with increasing olive oil (addition) at all levels of plasticizer. The WVP values obtained in this study were found to be affected more by the level of glycerol than the levels of olive oil.The results of this study indicated that by designing of edible films based on whey protein, in addition to improvement of excellent water wapor permeability, application of oil like olive oil can be prepared composite edible films with low permeability to water vapor.