Phenolic Compounds from the Fermentation of Cultivars Cabernet Sauvignon and Merlot from the Slovenian Coastal Region

Large scale fermentation of the cultivars Cabernet Sauvignon and Merlot from the Slovenian coastal region was performed in Bücher-Vaslin roto tank vinificators. Six different areas, Prade, Kortina, Škocijan, Ankaran, Labor and Hrvatini, were selected for this study to investigate total phenols, anthocyanins, tannins and colour density, as well as pH, titratable acidity, sugar content and ethanol. Anthocyanins and phenolic compounds were found to be in generally higher concentrations (up to 4240 mg/L) in Cabernet Sauvignon. Prolongation of the fermentation phase with Merlot gave even reduced concentrations of anthocyanins, a phenomenon which was not observed in Cabernet Sauvignon. The highest concentration of anthocyanins was found in Merlot from the Kortina location (735 mg/L), and in Cabernet Sauvignon from the Labor location (998 mg/L). The highest concentration of tannins (1828 mg/L) was found in the grapes of Cabernet Sauvignon from the Ankaran location, while in Merlot 1280 mg/L was detected in a sample from the Prade area. The tone of colour and its intensity reached full maturity in Cabernet Sauvignon. Merlot from the Kortina location reached the highest colour density of 1.57, while in a sample of Cabernet Sauvignon from Hrvatini colour density was 2.89. Only small differences were detected in colour quality between Merlot and Cabernet Sauvignon

Uloga mjerenja redoks-potencijala tijekom fermentacije mošta Sauvignon blanc

The aim of this work was to study the changes of the principal compounds of Sauvignon blanc grape must and wine during fermentation at the temperatures of 15, 18 and 24 °C and to compare the obtained results with the changes of redox potential. Among the changes of redox potential value, the levels of oxygen partial pressure, biomass, concentrations of reductive sugars (glucose and fructose), ethanol, glycerol and pH value, a good correlation was found. Redox potential was found as a valuable indicator of yeast metabolic activity in wine fermentation that enables an insight and control of the fermentation process.U radu je proučavana promjena glavnih sastojaka mošta Sauvignon blanc tijekom fermentacije pri temperaturama od 15, 18 i 24 °C a dobiveni su rezultati uspoređeni s promjenama redoks-potencijala. Utvrđena je dobra korelacija između promjena vrijednosti redoks-potencijala i parcijalnog tlaka kisika, količine biomase, koncentracije reduktivnih šećera (glukoza i fruktoza), etanola, glicerola i pH vrijednosti. Redoks-potencijal je vrlo koristan pokazatelj metaboličke aktivnosti kvasca tijekom fermentacije vina koji omogućuje uvid i praćenje procesa vrenja

UTJECAJ KONTOROLIRANE MALOLAKTIČNE FERMENTACIJE NA SASTAV HLAPIVIH SPOJEVA U VINIMA KRALJEVINE

The effect of malolactic fermentation (MLF) on the volatile composition of white wines made from autochtonous grape variety Kraljevina was studied by inoculation with selected lactic acid bacteria. At the end of malolactic fermentation, after the decomposition of the malic acid present in wine the non volatile compounds were analyzed by HPLC, while volatile compounds were analyzed by gas chromatography. All wines were also sensory analyzed. Results showed changes in acetaldehyde, some higher alcohols, ethyl esters, free and bound monoterpenes and some organic acids that contribute to enhance the sensory properties and quality of Kraljevina wines that underwent malolactic fermentation.Istraživan je utjecaj malolaktične fermentacije (MLF) na sastav hlapivih spojeva u vinima Kraljevine primjenom selekcioniranih mliječno kiselih bakterija. Malolaktična fermentacija te analiza nehlapivih spojeva provedena je na HPLC-u dok su hlapive komponente analizirane pomoću plinske kromatografi je. Sva vina također su i senzorno ocijenjena. Rezultati su pokazali promjene u koncentracijama acetaldehida, nekih viših alkohola, etil estera, slobodnih i vezanih monoterpena te pojedinih organskih kiselina što je pridonijelo poboljšanju senzornih svojstava i kvalitete vina Kraljevina u kojima je provedena malolaktična fermentacija

Influence of Temperature and Carbon Dioxide on Fermentation of Cabernet Sauvignon Must

In the process of wine fermentation temperature and the amount of carbon dioxide present represent parameters that can be easily monitored and controlled. The influence of variation of the process temperature and the fluxes of additional inlet gaseous carbon dioxide in Saccharomyces bayanus fermentation of Cabernet Sauvignon grape must on the accumulation of biomass and production of metabolites was studied. All experiments with temperature and redox potential control on-line were performed in a 10-litre laboratory stirred tank reactor. Metabolites of Saccharomyces bayanus fermentation comprising higher alcohols (1-propanol, 2-butanol, isoamyl alcohol), as well as reducing sugars, were measured off-line by gas and high pressure liquid chromatography

Influence of Temperature and Carbon Dioxide on Fermentation of Cabernet Sauvignon Must

In the process of wine fermentation temperature and the amount of carbon dioxide present represent parameters that can be easily monitored and controlled. The influence of variation of the process temperature and the fluxes of additional inlet gaseous carbon dioxide in Saccharomyces bayanus fermentation of Cabernet Sauvignon grape must on the accumulation of biomass and production of metabolites was studied. All experiments with temperature and redox potential control on-line were performed in a 10-litre laboratory stirred tank reactor. Metabolites of Saccharomyces bayanus fermentation comprising higher alcohols (1-propanol, 2-butanol, isoamyl alcohol), as well as reducing sugars, were measured off-line by gas and high pressure liquid chromatography

CHANGES IN VOLATILE COMPOSITION OF KRALJEVINA WINES BY CONTROLLED MALOLACTIC FERMENTATION

The effect of malolactic fermentation (MLF) on the volatile composition of white wines made from autochtonous grape variety Kraljevina was studied by inoculation with selected lactic acid bacteria. At the end of malolactic fermentation, after the decomposition of the malic acid present in wine the non volatile compounds were analyzed by HPLC, while volatile compounds were analyzed by gas chromatography. All wines were also sensory analyzed. Results showed changes in acetaldehyde, some higher alcohols, ethyl esters, free and bound monoterpenes and some organic acids that contribute to enhance the sensory properties and quality of Kraljevina wines that underwent malolactic fermentation

Phenolic Compounds from the Fermentation of Cultivars Cabernet Sauvignon and Merlot from the Slovenian Coastal Region

Large scale fermentation of the cultivars Cabernet Sauvignon and Merlot from the Slovenian coastal region was performed in Bücher-Vaslin roto tank vinificators. Six different areas, Prade, Kortina, Škocijan, Ankaran, Labor and Hrvatini, were selected for this study to investigate total phenols, anthocyanins, tannins and colour density, as well as pH, titratable acidity, sugar content and ethanol. Anthocyanins and phenolic compounds were found to be in generally higher concentrations (up to 4240 mg/L) in Cabernet Sauvignon. Prolongation of the fermentation phase with Merlot gave even reduced concentrations of anthocyanins, a phenomenon which was not observed in Cabernet Sauvignon. The highest concentration of anthocyanins was found in Merlot from the Kortina location (735 mg/L), and in Cabernet Sauvignon from the Labor location (998 mg/L). The highest concentration of tannins (1828 mg/L) was found in the grapes of Cabernet Sauvignon from the Ankaran location, while in Merlot 1280 mg/L was detected in a sample from the Prade area. The tone of colour and its intensity reached full maturity in Cabernet Sauvignon. Merlot from the Kortina location reached the highest colour density of 1.57, while in a sample of Cabernet Sauvignon from Hrvatini colour density was 2.89. Only small differences were detected in colour quality between Merlot and Cabernet Sauvignon

The Role of On-line Redox Potential Measurement in Sauvignon blanc Fermentation

The aim of this work was to study the changes of the principal compounds of Sauvignon blanc grape must and wine during fermentation at the temperatures of 15, 18 and 24 °C and to compare the obtained results with the changes of redox potential. Among the changes of redox potential value, the levels of oxygen partial pressure, biomass, concentrations of reductive sugars (glucose and fructose), ethanol, glycerol and pH value, a good correlation was found. Redox potential was found as a valuable indicator of yeast metabolic activity in wine fermentation that enables an insight and control of the fermentation process