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Abstract

Brettanomyces bruxellensis is one of the most important spoilage microorganisms in winemaking. It is harmful for wine industry because it produces volatile phenols, compounds primarily responsible for off-odours in wine. One of the possible solutions for preventing its growth is using new non-thermal processing technologies. The aim of this study was to investigate the application of one non-thermal processing technology, high power ultrasound and its combination with heating (thermosonication) on the inactivation of B. bruxellensis in red wine in batch systems. Various parameters, such as treatment duration (1, 2, 3, 6, 10 and 15 minutes), temperature (25, 35, 40 and 43 °C) and probe diameter (12.7 mm and 19.1 mm), were examined. The combination of high power ultrasound and heating (thermosonication) proved to be a better method compared to solely using high power ultrasound. However, the production of volatile phenols by B. bruxellensis was also reduced after high power ultrasound treatment. The optimal treatment of 3 min at 43 °C with high power sonicator at ultrasound frequency of 20 kHz with 12.7 mm diameter ultrasonic probe for complete inactivation of B. bruxellensis was determined.

Keywords: red wine, spoilage yeast, B. bruxellensis, high power ultrasound treatment, thermosonication

Sažetak

Brettanomyces bruxellensis jedan je od najvažnijih mikroorganizama koji uzrokuju kvarenje vina. Ovaj kvasac je štetan za industriju vina jer ima sposobnost stvaranja hlapivih fenola, spojeva koji su odgovorni za neugodan miris vina. Za sprečavanje njegova rasta mogu se primijeniti nove procesne tehnologije tzv. netermalne tehnologije. U ovom istraživanju ispitana je primjena ultrazvuka visoke snage kao i zajednička primjena ultrazvuka visoke snage i zagrijavanja (termosonifikacija) za šaržnu inaktivaciju B. bruxellensis u crnom vinu. Tijekom istraživanja ispitan je utjecaj različitih parametara kao što su trajanje tretiranja (1, 2, 3, 6, 10 i 15 minuta), temperatura (25, 35, 40 i 43 °C) i promjer sonde (12,7 i 19,1 mm). Utvrðeno je kako je zajednička primjena ultrazvuka visoke snage i zagrijavanja (termosonifikacija) bolja metoda za inaktivaciju ovog kvasca u odnosu na samostalnu primjenu ultrazvuka visoke snage. Ipak primjenom ultrazvuka visoke snage postignuta je smanjena proizvodnja hlapivih fenola pomoću kvasca B. bruxellensis. Potpuna inaktivacija kvasca B. bruxellensis postignuta je pri 43 °C primjenom ultrazvuka frekvencije 20 kHz i sonde promjera 12,7 mm kroz 3 minute.

Ključne riječi: crno vino, kvasac uzročnik...

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