Trub brewery waste as a novel and sustainable protein source for the development of active packaging materials

Trub, a byproduct generated during beer processing, possesses a protein-rich composition with significant potential for producing biodegradable films. This study developed a novel process for manufacturing trub-based films by optimizing the concentrations of biopolymer (trub) and plasticizer (glycerol) using an experimental design (2²). Films with higher trub concentrations exhibited elongation at break and tensile strength 6.7 and 3 times greater, respectively, and a reduction in permeability by approximately 43 %, compared to films with lower trub concentrations. Additionally, the films demonstrated opacity levels above 60.8 %, effectively blocking UV-light. The optimized condition (7 % trub and 30 % glycerol) exhibited in vitro antioxidant activity against free radicals and inhibited the growth of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). These findings suggest that trub-based films can serve as active packaging, providing a sustainable and cost-effective solution for preserving the physical and organoleptic properties of products.