High-power ultrasound as a trigger for extraction of proteins from brewery waste: optimization and techno-functional properties

Food wastes are important raw materials for obtaining valuable ingredients with broad applications in the food, cosmetic, and pharmaceutical sectors. This work aims to optimize the high-power ultrasound-assisted extraction (UAE) of proteins from brewer’s spent grains (BSG) using a factorial design (2³) and compare their nutritional and techno-functional properties with proteins obtained by conventional extraction (CME). The optimized UAE condition was 550 W, 10 min, and 65°C, resulting in concentrates with a protein content 8% higher than the CME in an extraction time reduced by 92%. Furthermore, the essential amino acid fraction was higher in UAE, providing good digestibility, antioxidant action, and technological properties (emulsification, foam, water and oil retention and solubility). Thus, the use of UAE to extract proteins from BSG is satisfactory, favoring the obtaining of protein concentrates with good technological, functional, and nutritional performances, enhancing their use as an ingredient in foods, pharmaceuticals, or cosmetics products.