Effect of phenolic compounds on the growth and L-malic acid metabolism of Oenococcus oeni.

In this work the effect of the most common phenol carboxylic acids, (gallic, caffeic and ferulic acids) and flavonoids (catechin and quercetin) on the growth and L-malic acid metbolism of Oenococcus oeni was investigated. A total of 143 strains, isolated from different wines, were assayed in a synthetic medium added with ethanol (12% v/v) and malic acid (5 g/L) and different amounts of each compound under analysis. The three carboxyl acids showed an inhibitory effect on growth of Oenococcus oeni at high concentrations; 1000 mg/L inhibited the growth, and inhibition by ferulic acid was greater than that registered for caffeic acid. As for gallic acid its presence in the medium at 500 mg/L stimulated the growth of assayed strains while higher concentrations, until 1000 mg/L did not inhibit the growth. Catechin had a stimulating effect, which increased with concentration. While quercetin showed a slight stimulating effect only at low concentrations. Flavonoids also stimulated the Malolactic fermentation.