Effect of sorbitol concentration on WPI-okra blended edible films

Abstract

The influence of sorbitol concentration as a plasticizer on the mechanical, optical, and barrier characteristics of whey protein isolate (WPI) films is examined in this thesis, with particular attention paid to the effects of sorbitol addition timing—either before or after denaturation. The study uses several analytical techniques, such as colorimetry, opacity, tensile testing, and measurements of water vapor permeability, to evaluate these effects. The findings showed that the physical and functional properties of WPI films are considerably changed by the addition of sorbitol. Films with sorbitol added after denaturation displayed lower opacity and higher L values in spectrophotometric testing, indicating increased lightness and transparency. These modifications imply enhanced visual clarity, which may be useful in applications needing those characteristics. Mechanically, the time of the sorbitol addition had a significant impact on the films' elongation and stress tolerance. Films that had sorbitol added after denaturation showed higher stress resistance, indicating a stronger, more densely cross-linked protein network, whereas films that had sorbitol added before denaturation showed enhanced elongation, suggesting superior flexibility. Films with post-denaturation sorbitol addition showed reduced water vapor permeability in terms of barrier qualities, suggesting a denser structure that could improve the protective barrier function required for sensitive packaging applications. The present study underscores the crucial significance of the timing of plasticizer addition in enhancing the functional characteristics of biopolymer films. The findings, which deal with maintaining food quality and extending shelf life, will have a significant impact for the food packaging industry. The results indicate that WPI films' qualities may be tailored to fit specific demands by varying the time of sorbitol addition, which can improve the films' use in environmentally friendly packaging solute.