Published in Scientific Papers. Series B, Horticulture, Vol. LXVII, Issue 1
Written by Cornel Daniel BANIŢĂ, Arina Oana ANTOCE, George Adrian COJOCARU
The medium chain saturated fatty acids (MCFA) are synthesized by the yeasts and released in fermentation media, where they contribute to fermentation aroma, but are also well known for their inhibitory effect on yeast growth. At low pH and in the presence of ethanol, only few mg/l of MCFA could arrest the AF. One of the mechanisms employed by the yeasts to protect themselves from the MCFA effects implies the conversion of the MCFA in ethyl esters, which are less toxic. In this way, fermentation aroma is even more enhanced, as ethyl esters of MCFA have more appealing sensorial qualities and are perceived at lower thresholds. Understanding MCFA’s occurrence in grape must and wine and their inhibitory mechanisms can be useful for a better predictability and control during winemaking process. Certain technological factors were found to dramatically affect the concentrations of MCFA during winemaking, among which are the grapes ripening process, several technological interventions during winemaking and the yeast strains, all influencing style and perceived quality of wines. Furthermore, due to their inhibitory effects on yeasts, the MCFA have drawn the attention of researchers and producers as agents able to reduce the doses of SO2 necessary for the cessation of alcoholic fermentation (AF) in order to obtain sweet wines. In this review inhibitory mechanisms are discussed, along with possible ways to control the MCFA concentrations during winemaking, also in the view of sweet wine production.
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