Proteolytic activity of Oenococcus oeni enables the increase in antioxidant and antihypertensive activities from wine.

Oenococcus oeni is a lactic acid bacterium involved in winemaking where it generally carries out the malolactic fermentation converting the wine's malic acid into lactic acid. In this work were used the strain m of Oenococcus oeni. The culture was inoculated at 108 Log CFU/mL in a synthetic wine medium (SW) supplemented with a fraction of high molecular weight constituted by proteins and polypeptides (FPP) obtained from Cabernet Sauvignon and Syrah wines from Colalao del Valle, Tucumán, Argentine. In presence of FPP, O. oeni maintains viability after 48 h incubation time and release an extracellular proteolytic activity. Therefore, a release peptides of 1.247 and 1.373 mg N/L at 48 h of incubation time was detected in SW supplemented with FPP from Cabernet Sauvignon and Syrah wines respectively. Concomitantly with the maximum peptide release, the "in vitro" biological activities were increased. The released peptides from Cabernet Sauvignon wine enables the increase in the ferric reducing antioxidant power (FRAP) capacity, the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), and the inhibition of angiotensin I-converting enzyme (ACEI activity) in 392.8 µmol FeSO4/L, 9.7% and 63.9%, respectively. In presence of FPP of Syrah wine, the released peptides increases in 156.5 µmol FeSO4/L, 5.5% and 13.8% the FRAP, DPPH and ACEI activities, respectively. The utilization of Oenococcus oeni m to carry out the malolactic fermentation would contribute to enhance the beneficial biological activities of the final product and provide an additional value to regional wines.

Increase in antioxidant and antihypertensive peptides from Argentinean wines by Oenococcus oeni.

Cells from an exponential Oenococcus oeni m1 culture in a grape juice medium were inoculated into a synthetic wine medium (SW) supplemented with a protein and polypeptide fraction (PPF) of high molecular weight (higher than 12,400 Da) obtained from four varietals of Cafayate Argentinean wines. O. oeni maintains viability after 48 h incubation time and enables the increase in extracellular proteolytic activity and the release of low molecular weight peptides by 1.067, 0.397, 0.915 and 0.705 mg N/L in the respective SW supplemented with PPF from Cabernet Sauvignon, Malbec, Tannat and Torrontés wine varietals. After 48 h incubation time, concomitantly with peptide release, an increase in antioxidant and antihypertensive activities was detected in all studied media. The highest increase was detected in the presence of PPF from Cabernet and Tannat wine varietals. Maximum increase in antioxidant activity (366.1 µmol FeSO4/L in the case of ferric reducing antioxidant power and 8.9% in 2,2-diphenyl-1-picrylhydrazyl radical scavenging) was produced by the peptides released from PPF of Cabernet Sauvignon wine. The peptides released from PPF Tannat wine varietal caused the highest increase in antihypertensive activity (56.2% in angiotensin I-converting enzyme inhibitory activity). Oenococcus oeni m1 would provide additional benefits to wine such as an increase in bioactive peptides with multifunctional beneficial activities.