Effect of ultrasonic pretreatment on enzymatic hydrolysis of proteins from food industry by-products and their functional properties

Abstract

This study evaluated the impact of ultrasonic pretreatment on the enzymatic hydrolysis of proteins from food industry by-products such as salmon frames, chicken pulp, and turkey pulp. The hydrolysis behavior and functional properties of the hydrolysates were analyzed, including their antioxidant, antimicrobial, and water-holding capacity. The results indicate that ultrasound significantly improved (p ≤ 0.05) the hydrolysis efficiency in chicken and turkey pulp, increasing the release of α-NH groups by up to 30 % compared to samples without ultrasound. Regarding the antioxidant capacity, the treated hydrolysates achieved 52 % capture of the DPPH radical and 51 % of the ABTS radical at a concentration of 10 mg/mL, these values being concentration-dependent and higher than those of sodium triphosphate (STPP). Regarding water-holding capacity, chicken pulp hydrolysates with ultrasonic pretreatment in continuous and discontinuous mode achieved a cooking loss of 19 %, representing a 58 % reduction compared to the negative control. Regarding antimicrobial capacity and at the concentrations evaluated, the treated hydrolysates did not show inhibition of bacteria representative of food-associated pathogens. These improvements highlight ultrasound as an effective tool to optimize enzymatic hydrolysis and revalorize food by-products.