Bioactive peptides in water-soluble extracts of ovine cheeses from Southern Brazil and Uruguay

Water soluble extracts (WSE) of ewe's cheeses produced in Uruguay and Brazil were evaluated for their biological activities. Feta-type, Roquefort-type and Pecorino-type cheeses from Brazil, Pecorino Sardo-type and Cerrillano cheese samples from Uruguay, were analyzed. Antioxidant properties were evaluated using distinct methods. Scavenging of the cation radical of 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) ranged from 32 to 45% for Feta-type cheeses to 87% for Roquefort-type cheese. A similar trend was observed for the reducing power, where WSE from Roquefort-type cheese showed the highest activity among the evaluated cheese. Iron chelating activity was quite variable among the different WSE, being higher (50%) for a Pecorino-type cheese. Thiobarbituric acid reactive substance (TBARS) analysis presented similarity among most of the cheese samples, with inhibition values ranging from 25 to 51%. Scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was observed only for Roquefort-type cheese. All WSE samples showed a prominent inhibition of angiotensin I-converting enzyme (ACE), ranging from 46% for a Feta-type cheese to 80% for Roquefort-type cheese. No antibacterial activity was observed for the different WSE. The results indicated that the evaluated cheeses could be sources of bioactive peptides with different modes of action. WSE of Roquefort-type cheese showed the best set of biological activities. Nano-ESI-MS/MS analysis allowed the identification of peptides that may contribute to the observed bioactivities. (C) 2012 Elsevier Ltd. All rights reserved.