Brewers' spent grain extract as antioxidants in starch-based active biopolymers

Brewer's spent grain (BSG) is a by-product of the brewery and represents a sustainable alternative for application in starch-based active materials. This study aimed to develop starch/poly(vinyl alcohol) films containing BSG extract, with focus on the influence of BSG on the mechanical, structural, and barrier properties of the films. The antioxidant potentials of the extract and the films were proved by ABTS. + (IC50 = 2.0 +/- 0.6 mu g mL(-1)) and DPPH. (IC50 = 196.05 +/- 018.66 mu g mL(-1)) assays. The addition of BSG extract did not have a significant impact on the mechanical performance and weight loss in water of the materials. The incorporation of the extract resulted in a rough surface, without pores and/or cracks. Controlled release of phenolic compounds was observed for BSG3 (3 g.100 g(-1) of BSG extract) (163.3 +/- 20.9 mgGAE.mL(-1)) and BSG5 (5 g.100 g(-1) of BSG extract) (165.7 +/- 23.6 mgGAE.mL(-1)) over a 4 h period. Therefore, this study shows the potential of BSG as an organic source of antioxidants for active biopolymers.

Automated summary

This study investigates the influence of brewer's spent grain (BSG) on the mechanical, structural, and barrier properties of starch/poly(vinyl alcohol) films. The results demonstrate that the BSG extract and films have strong antioxidant potentials, and the addition of the extract does not significantly affect the material properties. Controlled release of phenolic compounds from the BSG extract is observed under specific conditions.