Antioxidant potential of edible mushroom (Agaricus bisporus) protein hydrolysates and their ultrafiltration fractions.

Mushroom protein isolate (MPI) from Agaricus bisporus was hydrolyzed using Alcalase, Pancreatin, Flavourzyme, Alcalase-Pancreatin and Alcalase-Flavourzyme. The obtained hydrolysates (MPHs) were ultrafiltered to generate peptide fractions (UFs) of molecular sizes (<1, 1-3, 3-5 and 5-10kDa). The electrophoretic profile results indicated that the enzymatic systems were efficient in hydrolyzing the MPI into low molecular weight peptides. Hydrolysate yields of >57% and protein recoveries of >43% were obtained. Effective concentration that scavenged 50% (EC) of DPPH radicals was similar for the MPHs while inhibition against linoleic acid oxidation was strongest (66.49%) for Alcalase-Flavourzyme hydrolysate on day 5 of incubation. UFs exhibited a concentration-dependent FRAP, with the highest activity for fractions from Alcalase and Pancreatin recorded in 1-3kDa. The antioxidant activities of MPHs and their UFs suggested that they could be potential bioactive ingredients for use in the formulation of functional foods as well as natural antioxidants in lipid food systems.