Vicia villosa protein isolate: a new source of protein to make a biodegradable film

Abstract

Edible films from Vicia villosa protein isolate (VVPI) containing different contents of glycerol and sorbitol (30, 40, 50 and 60%w/w of protein) were developed. The aim of this study was to investigate the influence of type and concentration of plasticizers on the properties of edible films obtained from VVPI. Type and concentration of plasticizer significantly (p <0.05) affected the mechanical, barrier, thermal and surface properties as well as opacity of the films. As plasticizer concentration increased, tensile strength decreased concomitant with increase in elongation at break and water vapor permeability. The similar trend behavior was observed for the film solubility, which increased with increasing plasticizer concentration. Sorbitol plasticized films, showed higher film solubility compared to glycerol plasticized films. Sorbitol plasticized films provided the most tensile strength values; however, its effect on water vapor permeability was low. In contrast, glycerol plasticized films exhibited the least tensile strength values, resulting in increasing water vapor permeability. Opacity of glycerol plasticized films was lower than that of sorbitol plasticized films, and decreased with increasing plasticizer content ( p <0.05). Also, a significant decrease ( p <0.05) was observed in thermal features and surface hydrophobicity values with increasing in plasticizer contents. It was observed that the films plasticized with sorbitol had lower moisture content than those with glycerol.