Characterization of fruity aroma modifications in red wines during malolactic fermentation.

The role of malolactic fermentation (MLF) in the fruity aroma of red wines was investigated by an analytical study on more than 60 volatile compounds in 48 red wines made in varied conditions and supplemented by a sensory study. Lactic acid bacteria (LAB) modify the fruity notes of red wines but without a specific trend. The absence, in the short term, of a lactic mask was emphasized, whereas the existence of a smoked/toasted reduction-like mask note was evoked but not characterized. Variations in the composition of the fruity aroma markers were predominant. Although LAB β-glycosidase activities were not very involved, on the other hand, esterase seemed to play a central role that was sometimes associated with the metabolism of the sulfur-containing compounds. New insights in ester metabolism in enological LAB and the importance of wine composition on bacterial variations in metabolites and aromatic alterations were emphasized.