The impacts of Saccharomyces sp. and Lachancea thermotolerans yeast strains on changes in chemical composition of Frankovka wine

Proizvodnja vina složen je proces koji obuhvaća proces alkoholne fermentacije i ima vrlo dugu tradiciju. Proizvođači vina oduvijek su morali odgovarati na različite izazove brojnih čimbenika kako bi dobili vrhunski proizvod. U posljednje vrijeme cijeli svijet suočava se s klimatskim promjenama, grožđe pod utjecajem klimatskih promjena dozrijeva u uvjetima visokih prosječnih temperatura zraka, a česte su i ekstremno visoke temperature te duži sušni periodi. Posljedice klimatskih promjena su sve ranija berba grožđa i promjene u kemijskom sastavu vina, koje se očituju u višoj alkoholnoj jakosti zbog visokih koncentracija šećera, nedostatku kiselina te promjenama drugih spojeva koji imaju velik utjecaj na senzorna svojstva vina. Kao jedno od rješenja, tržište nudi selekcionirane sojeve Saccharomyces i ne-Saccharomyces kvasaca koji svojim metabolizmom mogu utjecati na neke od navedenih promjena u sastavu mošta i vina. Spomenuti sojevi kvasaca mogu smanjiti koncentraciju alkohola u vinu ili povećati ukupnu kiselost, a rezultat bi trebalo biti harmoničnije vino, užitnih senzornih svojstava. U ovom radu uspoređivane su tri varijante vina frankovka, fermentirane različitim sojevima selekcioniranih Saccharomyces cerevisiae i Lachancea thermotolerans kvasaca. Osnovna fizikalno-kemijska analiza provedena je prema metodama O.I.V.-a (2012), pojedinačne organske kiseline i ukupni polifenolni spojevi određeni su spektrofotometrijski, a pojedinačni polifenolni spojevi uz pomoć tekućinske kromatografije visoke djelotvornosti (HPLC). Glicerol je određen enzimatskom metodom. Statističkom analizom (ANOVA) utvrđene su razlike u kemijskom sastavu moštova i vina te utjecaju tretmana na kakvoću vina.Wine production is a complex process that includes alcoholic fermentation and has very long tradition. Winemakers have always had to respond to new challenges of a number of factors in order to get a product with the highest quality. Recently, the whole world has been facing climate change, grapes under the effects of climate change ripen in conditions of very high average of air temperatures and longer dry periods are very common. The consequences of climate change are earlier grape harvest and changes in the chemical composition of wine, which are manifested in higher alcohol content due to high sugar concentrations, lack of acids and changes in other compounds that have a great impact on the sensory characteristics of wine. As one of the solutions, the market offers selected strains of Saccharomyces and non-Saccharomyces yeasts, which by their metabolism can influence some of the mentioned changes in the chemical composition of must and wine. Mentioned strains of yeast can reduce the concentration of alcohol in the wine or increase the total acidity, and the result should be a more harmonious wine with complex sensory profil. In this research, three variants of Frankovka (Blaufränkisch) wine fermented by different strains of selected Saccharomyces cerevisiae and Lachancea thermotolerans yeasts, were compared. Basic chemical composition of wines was analyzed with the O.I.V. (2012) methods, individual organic acids and total polyphenolic compounds were determined spectrophotometrically, and individual polyphenolic compounds using high performance liquid chromatography (HPLC). Glycerol was determined by enzymatic method. Statistical analysis (ANOVA) revealed differences in the chemical composition of musts and wine and the impact of treatments on wine quality