Structural and material characterization of quercetin incorporated soy protein isolate films

Abstract

Owing to their degradability and fair film forming properties, protein films are captivating interest for development of packaging materials. However, poor water barrier properties and low mechanical strength limits its commercial application. Incorporation of additives such as phenolic compounds are reported to overcome these limitations. Our study aimed to explore the effect of quercetin and different processing methods on structural and mechanical properties of soy protein films. In our work, quercetin (flavonoid) was used to improve the material properties of proteinous films. The prepared films were evaluated for their physical properties, mechanical properties and water barrier capacity. The incorporation of quercetin had an obvious influence on the colour of film due to inherent pigmentation nature and resulted in generation of intense brown coloration of modified films. The opacity and cross linking of films were linearly increased with addition of quercetin. The mechanical properties of modified films were improved as indicated by increased tensile strength compared to the unmodified films. The incorporation of quercetin shifted the film towards hydrophilicity as indicated by increased water uptake activity of modified films compared to control films. Quercetin was found to form stable interaction with SPI as there was very little leaching observed from films. The results demonstrated that quercetin holds the potential to enhance the properties of SPI films which could be possibly employed in the development of packaging materials.