Effects of whey protein and glycerol concentrationon on physical properties of whey protein films

As public concerns grow over the quality, shelf-life of food products and the environmental impact of food producing process, more and more research have been devoted to developing edible or biodegradable films. This study aims to determine the influence of whey protein concentration, heating temperature, and glycerol:whey protein ratio on the characteristics of WPI edible films. Our results reveal that the whey solution turns into gel when heated at the concentration over 12%. As the concentration of WPI increases from 8% to 12%, thickness of whey protein films also increases. Glycerol, used as a plasticizer, affects the formation of films. The formation time, thickness and softness of films increase as the glycerol:whey protein ratio increases. There is no significant difference between heating at 80 ℃and 90 ℃ in film formation. Optimum conditions for film formation and physical properties are at WPI concentration of 10%, glycerol/WPI ratio(v/v) is 1∶1, heating at 80 ℃ for 30 min.