Biopolymeric films based on whey protein isolate/lignin microparticles for waste recovery

Abstract

Lignin is a source of phenolic compounds. It can be an excellent raw material for the production of films with whey protein isolate (WPI). The present study investigates WPI films with lignin microparticles (LMP). The structural, morphological, physical (thermal and mechanical analysis, water vapor barrier, color parameters, and transparency) properties, and the antioxidant properties were determined. The concentration of LMP were 0, 0.25, 0.50, and 0.75% (w/w). Structural analysis showed the addition of LMP to WPI-based films did not change the film structure. A good dispersion of the microparticles is observed for the treatments containing 0.25 and 0.50% (w/w) LMP. In the concentrations of WPI and LMP used, an improvement in the thermal (increase of 13.46°C in Tg) and mechanical properties (35% more resistant) were observed, as well as higher temperatures of degradation and lower water vapor barrier (12 and 16% for 0.25 and 0.50%, w/w, LMP). The films containing LMP showed antioxidant potential, with higher values for 0.75% (w/w) of LMP.