INCREASE OF ANTIHYPERTENSIVE PEPTIDES FROM NITROGENOUS MACROMOLECULAR FRACTION OF ARGENTINEAN RED WINE BY OENOCOCCUS OENI EXOPROTEASE.

AREDES FERNÁNDEZ, PEDRO; MANCA DE NADRA, MARÍA C

Rosario. Santa Fe.

Congreso; V Congreso Argentino de Microbiología General. SAMIGE.; 2008

SAMIGE

Hypertension is a risk factor for cardiovascular disease and stroke. Angiotensin-converting enzyme (ACE) hydrolyze the inactive Angiotensin I and release Angiotensin II, which exercises a powerful vasoconstrictive action, with the consequent increase in artery pressure. Different peptides with ACE-inhibitory (I-ACE) activity have been isolated from different food sources, released after hydrolytic or fermentation processes. Its in situ production, can confer to food product an additional beneficial property.The nitrogenous macromolecular fraction (NMF) of wines is comprised by, amino acids, peptides and proteins. The few studies carried out in wine, demonstrated that the low molecular weight peptides have I-ACE activity. Oenococcus oeni X2L, isolated from argentinean red wine, release an exoprotease to medium that can modify the peptidic fraction and their biological activity. The objective of this research was determine the I-ACE activity in the NMF of wine, and evaluate the increase of this activity by the presence of the O. oeni X2L exoprotease.NMF was isolated from a commercial red table wine. Wine was dialyzed 48 h against tap water using a 5000 Da pore size membrane. The retentate was vacuum concentrate and lyophilized. O. oeni X2L was grown in grape juice basal medium pH 4.8. In exponential growth phase, cells were harvested, washed and resuspended in citrate buffer 0.05 mol/l pH 5.0 during 2h at 20ºC for starvation. Cells were removed and the proteolytic activity was assayed in the supernatant by Cd-ninhydrin method. NMF was dissolved in citrate buffer pH 5.0 at concentrations of 100, 150, 200 and 500 % with respect to original concentration in wine. Same concentrations of NMF were dissolved in the O. oeni supernatant and incubated 60 min at 30°C. I-ACE activity percentage of each NMF solutions was measured by Cushman and Cheung method.The untreated NMF solutions, at concentrations of 100, 150, 200 and 500 % showed I-ACE inhibitory percentage of 19.42, 45.39, 50.53 and 49.84 respectively. Protease activity detected in O. oeni supernatant, achieve a maximum of 2.08 mmol/l. NMF treated with O. oeni supernatant, showed an increase of free amino acid concentrations of about 30 %, indicating peptide hydrolysis. The I-ACE activity percentage of NMF treated with O. oeni exoprotease, achieving values of 35.56; 50.53, 65.83 and 52.34 for the 100; 150; 200 y 500 % of NMF concentrations respectively.The I-ACE activity of the NMF of argentinean red wine was demonstrated for a first time. Maximum I-ACE inhibitory percentage was detected whit the NMF at double concentration with respect to wine. O. oeni X2L exoprotease have an effective action on peptide hydrolysis of NMF and increase I-ACE activity in all samples assayed, possibly due to either a increase of the concentration of bioactive peptides or a release of peptides with higher activity.