Characterization of edible films from whey proteins treated with heat, ultrasounds and/or transglutaminase. Application in cheese slices packaging

Abstract

Application of high power ultrasound and microbial transglutaminase addition, and their combination, have been studied for the modification of protein structure and crosslinking in order to change the properties of whey protein concentrate edible films. They were compared to untreated and heat-treated films (from heat-treated solutions). Ultrasound treatment modified some film properties. Water vapor permeability of ultrasound-treated films was slightly lower than those of untreated and heat-treated films. Ultrasound treatment increased tensile and puncture strengths of films in comparison with untreated samples. Transglutaminase addition only increased puncture deformation values and made films less green, more yellow and darker than non-added films. Heat treated films showed better mechanical properties and were selected for a preliminary evaluation as separation material of cheese slices; they exhibited similar results regarding slice separation easiness and slice wholeness after separation that the commercial material, without modifying cheese color and odor.