Biodegradable Active Packaging Based on an Antioxidant Extract from Brewer’s Spent Grains: Development and Potential of Application

New food packaging technologies are being developed as alternatives to synthetic polymers. Biodegradable active packaging from natural and sustainable sources has gained prominence by considering a circular economy and extending the food shelf life. This study aimed to develop and characterize an active biodegradable packaging based on cassava starch and poly(vinyl alcohol) with the brewer’s spent grain extract (BSGE) as a natural antioxidant. The BSGE was evaluated for its antioxidant activity using the ABTS●+ and DPPH● methods, and the total phenolic content (TPC) was determined, showing a high antioxidant potential, with values of IC50 of 185.95 μg/mL (ABTS●+) and >250.00 μg/mL (DPPH●) and the TPC of 263.23 ± 10.97 mg EAG/g of extract. The increase in the concentration of the BSGE in the active film formulations resulted in an increase in their thickness and density due to higher soluble solids in the extract samples. The films did not experience negative impact on their tensile strength and elongation at break when higher concentrations of the BSGE were added; also, their microstructural characteristics were preserved, which makes them potential candidates for being applied as active food packaging. The release of the TPC from the films in water media occurs with a higher intensity in the initial stages. These results indicate that biodegradable active films with higher concentrations of the BSGE (10BSGE) have potential as sustainable and efficient packaging for food preservation, contributing to the reduction of the environmental impact and adding value to the industrial byproducts.