The oenological interest of fumaric acid: Stop malolactic fermentation and preserve the freshness of wines

Abstract

One of the problems related to the increase in average temperatures in the wine-growing regions is the lower accumulation of organic acids in the berries. Wine freshness depends to a great extent on its acidity. In this study, the effectiveness of fumaric acid to inhibit malolactic fermentation or to stop it once initiated is evaluated. The main objective is to avoid the transformation of malic acid and thus preserve the freshness of wines made in warm areas. For this, different doses of fumaric acid (150, 300, 600 and 900 mg/L), lactic acid (2 and 4 g/L), SO 2 (50 and 100 mg/L), and lysozyme (200 and 500 mg/L) were tested. The ability of these compounds to inhibit bacterial development and stop the malic acid degradation was tested on a red wine of the variety Vitis vinifera L. cv. Tempranillo whose malic acid content was set at 1.5 g/L. The control wine inoculated with 6 log CFU / mL of Oenococus oeni finished the malolactic fermentation in 12 days. However, the use of doses equal to or greater than 300 mg/L of fumaric acid delayed the onset of malolactic fermentation for more than 50 days with little degradation of malic acid. In addition, fumaric acid proved to be effective in stopping a malolactic fermentation already started where the bacterial count was 7 log CFU/mL. Fumaric acid can be considered as a potent inhibitor of malolactic fermentation. This technological strategy allows the production of fresh wines with microbiological stability and low sulfur dioxide requirements.