MALOLACTIC FERMENTATION OF WINE - STUDY OF THE INFLUENCE OF SOME PHYSICOCHEMICAL FACTORS BY EXPERIMENTAL-DESIGN ASSAYS

The ability of selected lactic acid bacteria to carry out malolactic f ermentation depends on the level of numerous wine characteristics. A H adamard's experimental matrix was used to determine the main effects o f 11 physico-chemical factors on malolactic activity of three Leuconos toc anos strains and one Lactobacillus plantarum strain. Ethanol had t he greatest inhibitory effect on the achievement of malolactic ferment ation for all Leuc. oe nos strains. An inhibitory effect of the L-mali c acid was also found in the operating conditions. These strains show different degrees of sensitivity to pH. One of these strains was inhib ited by SO2. Malolactic activity of the Lact. plantarum strain is main ly affected by a low pH, and this strain is often less efficient than Leuc, oe nos strains. This methodology could be used for the selection of strains for malolactic starters. Further work is in progress using factorial design in order to determine the interactions between influ ential factors.