engleski

Effect of Malolactic Fermentation on Acidity, some Aroma Compounds and Sensory Properties of Riesling Wine

Changes in acidity, some aroma compounds and sensory properties caused by malolactic fermentation (MLF) were investigated in Riesling wine. Wine from the 1998 harvest season was made by usual method for white wines. After completion of alcoholic fermentation, wine was racked and divided into glass bottles (V=35 L) according to the following treatments. The first one was suppressed MLF with SO2 and stored at 10 0C. The second treatment included natural MLF, the third MLF was induced with starter culture Viniflora oenos. All treatments were done in triplicate. When MLF was completed, wines were sulfited, analyzed and tasted. Organic acid analysis was performed by HPLC and analysis of volatile compounds was done by the method of gas chromatography. Malic acid decomposition was completed in wines of all MLF variants and the result was lowering of total acidity and raising of pH value of wine. MLF wines contained lower concentrations of isoamyl acetate and higher concentration of ethyl lactate. During the period of investigation the concentration of higher alcohols, other acetates, ethyl esters of fatty acids, diethyl succinate and volatile acids was also examined. Wines of suppressed MLF were of inferior quality compared with malolactic fermented wines, while natural malolactic fermented wines were of significantly better quality.

malolactic fermentation; acids; volatile compounds; sensory properties; wine.

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