CONICET | Buscador de Institutos y Recursos Humanos

Peptides with biological activities can be released from inactive precursors (proteins-polypeptides) during food fermentation. Oenococcus oeni X2L from wine express a proteolytic system under the stresses conditions present in winemaking and thus could improve the biological properties by acting on the nitrogen compounds released by yeast autolysis at the end of alcoholic fermentation.In this work, we evaluated the modification of ACE-inhibitory (IACE) and antioxidant activities by O. oeni X2L sequentially inoculated in a model wine with autolysed Saccharomyces cerevisiae mc2. Microbial growth was determined by optical density and viable cell count. Nitrogen compounds were measured by Doi method; IACE activity by Cushman and Cheung; antioxidant capacity by ferric reducing/antioxidant power (FRAP) and DPPH radical scavenging activity methods. S. cerevisiae mc2 grown in YPD medium 24 h at 30°C, was suspended in a model synthetic wine and put under accelerated autolysis at 55 °C, stirred at 70 rpm during 24 h. Cultures obtained at 0 (control) and 24 h were filtered by 0.22 µm and inoculated with O. oeni X2L to reach 108 cell/ml. O. oeni inoculated in the synthetic wine without yeast autolysis, did not significantly modify the peptide release as well as antioxidant and antihypertensive activities. After 24 h of yeast autolysis, an increase of 1.42.mg N/L peptide concentration related to the control was determined after 48 h O.oeni growth. Also, FRAP and DPPH activities showed a significantly increase. Even if I-ACE increase from 18 to 45 % after 24 h of yeast autolysis, this activity was high (53%) when O. oeni was subsequently inoculated. The results obtained in this work suggest that O. oeni X2L could contribute to improving the quality of the wine, due to the increase of biological activities studied, probably related to the release of bioactive peptides from this proteolytic activity