Page 11 - MALOLACTIC FERMENTATION – IMPORTANCE OF WINE LACTIC ACID BACTERIA IN WINEMAKING

A HISTORY OF LACTIC ACID BACTERIA IN WINE
(2009) reported intracellular esterase activity in O. oeni. Christen et al. (2011) studied the me- tabolism of free and SO2-bound acetaldehyde by wine LAB. The duration of MLF in Riesling wine was strain-dependent (figure 2). Except for four strains, all O. oeni strains depleted malic acid within 17 to 22 days. The other four strains required 27 to 45 days to complete malic acid degradation, and the control did not undergo MLF. The degradation of acetaldehyde was completed 2 to 10 days after the degradation of malic acid. The authors concluded wine LAB play an essential role in acetaldehyde removal after the AF completes, and proposed delaying the SO2 addition until one week after L-malic acid disappeared. It was thought that, by so doing, bound-SO2 levels would be reduced by up to 75%.
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Figure 2. Degradation of malic acid (top graph) and acetaldehyde (bottom graph) by 12 strains of commercial wine lactic acid bacteria in a Riesling wine
Flamini et al. (2002) attributed lessening of vegetal notes to degradation of ethanal and high- er aldehydes such as hexanal and heptanal by LAB during MLF.
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Acetaldehyde (mg/L) Malate (mg/L)