Enzymatic hydrolysis as a valorization strategy of bovine lungs: Optimization of process variables and study of antioxidant capacity

Abstract

Background: The increase in meat production would also imply an increase in the generation of by-products or edible offal. These by-products can be used, due to their high protein content, as a substrate to obtain hydrolysates with functional activities. This study aimed to valorize bovine lungs by producing hydrolysates with antioxidant capacity. Results: A response surface methodology study was carried out using a central composite design in which factors were temperature (43.2–76.8 C), enzyme/substrate ratio [ES: 0.65–4.85% (w/w)] using Alcalase 2.4 L/Flavourzyme (1:1) and pH (5.8–9.2). The antioxidant capacity of the obtained BLH (bovine lung hydrolysates) was evaluated by the ABTS, DPPH, and FRAP methods. The maximum antioxidant capacity was achieved at 53. C, ES ratio of 2.3% (w/w), and pH of 8.2. Under optimal hydrolysis conditions, the antioxidant capacity increased rapidly from the beginning of the reaction to 30 min, reaching a maximum at 120 min; then, it decreased until the end (180 min). The degree of hydrolysis increased as hydrolysis occurred up to a maximum of 45%. Molecular weight distribution of BLH evaluated by Tricine-SDS-PAGE and SEC-FPLC showed that bovine lung proteins hydrolyzed for 120 min presented low molecular weight peptides (<5 kDa), which are absent in the non-hydrolyzed sample. Conclusion: In this work, we optimized the variables for producing BLH with antioxidant capacity using commercial proteases in a short reaction time, making it a worthwhile strategy for the recovery of by-products from the meat industry.