Exploration of potential of different fungi in protease production and analysis of capacity to produce active peptides

Functional peptides are short aminoacidic sequences that could contribute to human health. Functional peptides possess a wide range of bioactivities. Hence, a growing interest in these kinds of molecules, mainly focused on studying their different production strategies and respective economic and technological challenges, is increasing, where enzymatic hydrolysis is one of the leading strategies for their generation. The aim of this study is to find new sources of fungal proteases with antioxidant peptide production potential. A screening of 17 fungal strains with proteolytic activity was achieved, employing a skimmed milk medium. Six fungal strains were selected to study their proteolytic kinetics profile, and two of them were evaluated for their capacity to produce bioactive peptides from calcium caseinate through enzymatic hydrolysis. ABTS, DPPH, and FRAP assays measured the antioxidant activity of the peptides obtained. Blakeslea trispora and Rhizomucor pusillus were the higher proteolytic strains (1–4 EU/mL), and their crude extracts after caseinate hydrolysis generated an inhibition percentage of ABTS radical between 53.6–65.1%, 33.4–52.4% in DPPH and 496.8–690.8 µM Fe 2+ /g of lyophilized peptides. Both enzymatic extracts are reliable to be used in the production of antioxidant peptides .