INCREASE OF ANTIOXIDANT AND ANTIHIPERTENSIVE ACTIVITIES BY Oenococcus oeni INOCULATED IN A MODEL WINE WITH YEAST AUTOLYSED

AREDES FERNÁNDEZ, PA; STIVALA, MG; RODRÍGUEZ VAQUERO, MJ; FARÍAS, ME

San Diego

Congreso; 110th General Meeting of the American Society for Microbiology.; 2010

ASM

Peptides with biological activities can be released from inactive precursors (proteins-polypeptides) during food fermentation. Yeast autolysis is a common process that takes place after alcoholic fermentation. Nitrogen compounds represent the major fraction of compounds released by yeast during autolysis, which is formed mainly by peptides. Oenococcus oeni X2L from wine is able to express a proteolytic system under the stresses conditions present in winemaking. The aim of this work was to study the modification of ACE-inhibitory and antioxidant activities by O. oeni X2L in a model wine where a culture of Saccharomyces cerevisiae mc2 was autolysed under accelerated conditions. Microbial growth was determined by optical density measurement and viable cell count in agar plates. Amino acid and peptide concentrations were measured by Doi method. I-ACE activity percentage was measured by Cushman and Cheung method. Antioxidant capacity was evaluated by ferric reducing/antioxidant power (FRAP) and DPPH radical scavenging activity methods. S. cerevisiae mc2 was grown in YPD medium 24 h at 30°C. Cells were collected, washed three times with saline solution and suspended in a model synthetic wine. Accelerated autolysis was conducted at 55 °C in shaker at 70 rpm during 24 h. The cultures obtained at 0 and 24 h was filtered by 0.22 µm and inoculated with washed cells of O. oeni X2L obtained from an exponential culture in MRS-tomato juice medium. O. oeni sustain a cell viability of 108 after 48 h incubation in the model synthetic wine before and after yeast autolysis. An increase of 3.28 mg N/L of peptides was detected after yeast autolysis. In the medium inoculated with O. oeni before yeast autolysis, no significantly changes were detected in peptide release as well as antioxidant and antihypertensive activities. In synthetic wine medium after yeast autolysis, O. oeni increase peptide concentration in 1.54 and 1.42.mg N/L at 24 and 48 h respectively. At the same times FRAP and DPPH activities showed a significantly increase. I-ACE activity percentage, increase from 18 to 45 % after yeast autolysis. Subsequently, in presence of O. oeni, the I-ACE activity increase to 53 % at 48 h. Yeast lysis produced an important increase of peptide release and antioxidant an antihypertensive activities. Afterward, O. oeni inoculated in yeast autolysed medium, produced a positive effect on the biological activities studied. This behavior is related to the proteolytic activity of the bacterium that release active peptides.