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

INFLUENCE OF AUTOCHTHONOUS SACCHAROMYCES SPP. STRAINS ON THE SULFUR DIOXIDE CONCENTRATION IN WINE

Cilj ovoga rada bio je istražiti utjecaj 8 autohtonih sojeva kvasaca na sintezu sumpornog dioksida. U tu svrhu korišteni su moštovi Traminca, Rizvanca i Chardonnaya. Korišteni sojevi kvasaca bili su iz kolekcije Zavoda za mikrobiologiju, Agronomskog fakulteta Sveučilišta u Zagrebu. Pet od njih je H2S negativno a tri H2S pozitivno. Ispitivani sojevi kvasca stvorili su od 19 pa sve do 45 mg/l sumpornog dioksida. Najviše sumpornog dioksida stvorio je jedan od H2S pozitivnih sojeva. Rezultati su pokazali da je početna koncentracija šećera vrlo važna pri proizvodnji sumpornog dioksida. Kvasci su bili produktivniji pri višim razinama šećera.The aim of this work was to study the infl uence of 8 autochthonous yeasts strains on the sulfur dioxide formation. For this purpose grape must from the Traminer, Muller Turgau and Chardonnay grapes was used. Yeast strains used were cultivated at the Department for Microbiology, Faculty of Agriculture, University of Zagreb. Five of them were H2S negative and three H2S positive. Tested yeast strains produced from 19 up to 45 mg/l of sulfur dioxide. The highest sulfur dioxide producer was one of the H2S positive yeast strains. The results indicated the initial sugar concentration to be very important for the ratio of sulfur dioxide production. Yeasts were more effi cient at higher sugar levels

PROMJENE U KEMIJSKOM SASTAVU I SENZORNIM SVOJSTVIMA VINA VUGAVA DOZRIJEVANOG U BARIK BAČVICAMA OD HRVATSKE HRASTOVINE

Vugava musts were fermented in medium-toasted Croatian barrique barrels (225 L) made from Quercus petrea and Q. robur oak wood. The oak species used in this research infl uenced the specifi c change of the aroma structure of Vugava wines. During the age period the increase in the concentration of cis and trans oaklactons, guaiacol, eugenol, furfural and 5-methylfurfural was noted. Wines fermented and aged in Q. petrea barrels have higher concentrations of most volatile phenols compared to wines from Q. robur oak wood. From the organoleptic point of view this study suggested that fermentation and on the lees ageing production method in Croatian oak barrels positively infl uenced the quality of Vugava wines where best results were achieved by use of Q. petrea oak wood.Moštovi od grožđa Vugave fermentirali su u srednje paljenim hrvatskim barik bačvicama od hrasta kitnjaka i hrasta lužnjaka. Kemijska analiza hlapivih spojeva provedena je odmah po završetku alkoholne fermentacije te nakon 12 mjeseci dozrijevanja. Vrsta hrastovog drveta korištena u istraživanju značajno je utjecala na aromastski sastav vina Vugava. Posebice je uočena razlika u koncentracijama cis i trans hrastovog laktona, guajakola, eugenola i furfurala. Tijekom perioda starenja vina došlo je do promjena u sastavu većine hlapivih komponenti posebice furfurala, 5- metilfurfurala te hrastovih laktona. Dobiveni rezultati istraživanja ukazuju na pozitivan utjecaj hrvatske hrastovine na kakvoću vina Vugave

CHANGES IN VOLATILE COMPOSITION AND SENSORY PROPERTIES OF VUGAVA WINES AGED IN CROATIA OAK BARRELS

Vugava musts were fermented in medium-toasted Croatian barrique barrels (225 L) made from Quercus petrea and Q. robur oak wood. The oak species used in this research infl uenced the specifi c change of the aroma structure of Vugava wines. During the age period the increase in the concentration of cis and trans oaklactons, guaiacol, eugenol, furfural and 5-methylfurfural was noted. Wines fermented and aged in Q. petrea barrels have higher concentrations of most volatile phenols compared to wines from Q. robur oak wood. From the organoleptic point of view this study suggested that fermentation and on the lees ageing production method in Croatian oak barrels positively infl uenced the quality of Vugava wines where best results were achieved by use of Q. petrea oak wood

INFLUENCE OF AUTOCHTHONOUS SACCHAROMYCES SPP. STRAINS ON THE SULFUR DIOXIDE CONCENTRATION IN WINE

Cilj ovoga rada bio je istražiti utjecaj 8 autohtonih sojeva kvasaca na sintezu sumpornog dioksida. U tu svrhu korišteni su moštovi Traminca, Rizvanca i Chardonnaya. Korišteni sojevi kvasaca bili su iz kolekcije Zavoda za mikrobiologiju, Agronomskog fakulteta Sveučilišta u Zagrebu. Pet od njih je H2S negativno a tri H2S pozitivno. Ispitivani sojevi kvasca stvorili su od 19 pa sve do 45 mg/l sumpornog dioksida. Najviše sumpornog dioksida stvorio je jedan od H2S pozitivnih sojeva. Rezultati su pokazali da je početna koncentracija šećera vrlo važna pri proizvodnji sumpornog dioksida. Kvasci su bili produktivniji pri višim razinama šećera.The aim of this work was to study the infl uence of 8 autochthonous yeasts strains on the sulfur dioxide formation. For this purpose grape must from the Traminer, Muller Turgau and Chardonnay grapes was used. Yeast strains used were cultivated at the Department for Microbiology, Faculty of Agriculture, University of Zagreb. Five of them were H2S negative and three H2S positive. Tested yeast strains produced from 19 up to 45 mg/l of sulfur dioxide. The highest sulfur dioxide producer was one of the H2S positive yeast strains. The results indicated the initial sugar concentration to be very important for the ratio of sulfur dioxide production. Yeasts were more effi cient at higher sugar levels

The ocean sampling day consortium.

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world's oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

The ocean sampling day consortium

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

The Ocean Sampling Day Consortium

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

PROMJENE U KEMIJSKOM SASTAVU I SENZORNIM SVOJSTVIMA VINA VUGAVA DOZRIJEVANOG U BARIK BAČVICAMA OD HRVATSKE HRASTOVINE

Vugava musts were fermented in medium-toasted Croatian barrique barrels (225 L) made from Quercus petrea and Q. robur oak wood. The oak species used in this research infl uenced the specifi c change of the aroma structure of Vugava wines. During the age period the increase in the concentration of cis and trans oaklactons, guaiacol, eugenol, furfural and 5-methylfurfural was noted. Wines fermented and aged in Q. petrea barrels have higher concentrations of most volatile phenols compared to wines from Q. robur oak wood. From the organoleptic point of view this study suggested that fermentation and on the lees ageing production method in Croatian oak barrels positively infl uenced the quality of Vugava wines where best results were achieved by use of Q. petrea oak wood.Moštovi od grožđa Vugave fermentirali su u srednje paljenim hrvatskim barik bačvicama od hrasta kitnjaka i hrasta lužnjaka. Kemijska analiza hlapivih spojeva provedena je odmah po završetku alkoholne fermentacije te nakon 12 mjeseci dozrijevanja. Vrsta hrastovog drveta korištena u istraživanju značajno je utjecala na aromastski sastav vina Vugava. Posebice je uočena razlika u koncentracijama cis i trans hrastovog laktona, guajakola, eugenola i furfurala. Tijekom perioda starenja vina došlo je do promjena u sastavu većine hlapivih komponenti posebice furfurala, 5- metilfurfurala te hrastovih laktona. Dobiveni rezultati istraživanja ukazuju na pozitivan utjecaj hrvatske hrastovine na kakvoću vina Vugave