Effect of whey protein purity and glycerol content upon physical properties of edible films manufactured therefrom

Abstract

a b s t r a c tThis manuscript describes the detailed characterization of edible films made from two different protein products e whey protein isolate (WPI) and whey protein concentrate (WPC), added with three levels of glycerol (Gly) e i.e. 40, 50 and 60%(w/w). The molecular structure, as well as barrier, tensile, thermal, surface and optical properties of said films were determined, in attempts to provide a better understanding of the effects of proteinaceous purity and Gly content of the feedstock. WPI films exhibited statistically lower (p < 0.05) moisture content (MC), film solubility (S), water activity, water vapor permeability (WVP), oxygen and carbon dioxide permeabilities (O 2 P and CO 2 P, respectively) and color change values, as well as statistically higher (p < 0.05) density, surface hydrophobicity, mechanical resistance, elasticity, extensibility and transparency values than their WPC counterparts, for the same content of Gly. These results are consistent with data from thermal and FTIR analyses. Furthermore, a significant increase (p < 0.05) was observed in MC, S, WVP, O 2 P, CO 2 P, weight loss and extensibility of both protein films when the Gly content increased; whereas a significant decrease (p < 0.05) was observed in thermal features, as well as in mechanical resistance and elasticity e thus leading to weaker films. Therefore, fundamental elucidation was provided on the features of WPI and WPC germane to food packaging e along with suggestions to improve the most critical ones, i.e. extensibility and WVP.

Keratin/Polyvinyl Alcohol Blend Films Cross-Linked by Dialdehyde Starch and Their Potential Application for Drug Release

“…The film side facing the casting plate was shiny, while the other side was dull, probably due to the polymer arrangement during solvent evaporation. This phenomenon was also observed for whey protein isolate films by Óscar et al [33].…”

Development of chitosan based edible films: process optimization using response surface methodology

“…4a, b and c) however, it increased with the decrease in glycerol level (Fig. 4a Ramos et al (2013). They documented that increase in glycerol level in the formulation of whey protein concentrate films lead to increase in the reflection of light on the film surface, recorded higher L* values.…”

“…Packaging films have a significant influence on the appearance and consumer's acceptance of the products. Instrumental colour profile is of prime importance to determine the effect of films on the product appeal and consumer acceptability (Ramos et al 2013). The following equation showed a quadratic relationship between the independent and dependent variable.…”

“…This property is important to prevent lipid oxidation induced by UV light in food system (Leceta et al 2013;Ramos et al 2013). Hence, it is an important parameter to evaluate the efficacy of packaging films for foods (Leceta et al 2013).…”

Characterization of Carrageenan Edible films Plasticized with Glycerol

“…Farahnaky et al (2013) menjelaskan bahwa peningkatan konsentrasi gliserol dapat meningkatkan daya larut edible film karena sifat gliserol sebagai pembentuk plastis. Beberapa hasil penelitian menunjukkan bahwa peningkatan konsentrasi gliserol sebagai pemlastis secara umum dapat meningkatkan daya larut edible film (Ghasemlou et al 2011;Vieira et al 2011;Ramos et al 2013).…”