Utjecaj različitih načina provedbe jabučno-mliječne fermentacije na promjene kemijskih svojstava i hlapivih komponenti crnog vina Teran (Vitis vinifera L.)

Malolactic fermentation (MLF) is a complex biochemical process playing an important role in the production of red wines. The main reasons for its implementation are the reduction of titratable acidity and the consequent increase of pH, microbiological stability of wine, and changes in aromatic and sensory properties of wine. The aim of this study was to determine the compatibility of yeast and bacteria used by different malolactic fermentation techniques and their influence on the fermentation duration, concentration of individual organic acids, aroma compounds, and on chemical and sensory properties of Teran wines. The experiment included control treatment (without MLF), spontaneous MLF, induced MLF at the beginning of alcoholic fermentation with simultaneous inoculation of yeast and bacteria (coinoculation) and induced MLF after alcoholic fermentation (sequential MLF). In the co-inoculation treatment MLF had no negative effect on the alcoholic fermentation kinetic. Alcoholic fermentation was complete in all treatments. Coinoculation resulted in a significantly shorter duration of the MLF process. In all MLF treatments, significant reduction of titratable acidity and the increase of pH values was noted. Wines of the spontaneous MLF treatment obtained the highest concentration of volatile acidity and ethyl acetate. In all MLF treatments a complete consumption of malic acid and a decrease in concentration of citric acid, total amount of higher alcohols, and acetaldehyde were observed. Furthermore, significantly higher concentrations of ethyl esters, diacetyl, acetoin, and 2,3 butanediol were present in wines from all MLF treatments.Jabučno-mliječna fermentacija (JMF) složen je biokemijski proces koji ima važnu ulogu u proizvodnji većine crnih vina. Glavni učinci primjene JMF su snižavanje ukupne kiselosti uz rast pH vrijednosti, mikrobiološka stabilnost vina te promjena aromatskih senzornih svojstava vina. Cilj ovog istraživanja bio je utvrditi utjecaj različitih načina jabučnomliječne fermentacije na kompatibilnost kvasca i bakterija, duljinu trajanja fermentacije, koncentraciju pojedinačnih organskih kiselina i spojeva arome te senzorna svojstva vina sorte ´Teran´ (Vitis vinifera L.). Pokus je obuhvaćao kontrolni tretman (bez JMF), spontanu JMF, induciranu JMF u početku alkoholne fermentacije (koinokulacija) te induciranu JMF po završenoj alkoholnoj fermentaciji. U svim tretmanima alkoholna fermentacija je u potpunosti završila, bez zastoja ili usporavanja. Koinokulacija je utjecala na značajno kraće trajanje JMF. Svi tretmani s JMF značajno su utjecali na sniženje koncentracije titracijske kiselosti i povećanje pH vrijednosti. Najviše koncentracije hlapive kiselosti i etil acetata utvrđene su u vinima spontane JMF. U svim tretmanima s JMF zabilježena je potpuna razgradnja jabučne kiseline te sniženje koncentracije limunske kiseline, ukupnih viših alkohola i acetaldehida. Nadalje, značajno više koncentracije etilnih estera, diacetila, acetoina i 2,3-butandiola zabilježene su u svim tretmanima s JMF