Bentonite application in the production of Malvazija istarska wine

U vinogradarsko-vinskoj proizvodnji u posljednje vrijeme sve je češći problemi pojava visokih temperatura posebice u periodu dozrijevanja koje mogu utjecati na intenzivniju sintezu proteina u grožđu. Time se narušava kvaliteta vina u boci zbog pojave taloga i mutnoće kao rezultat denaturacije nestabilnih oblika proteina. Stoga je cilj ovoga rada bio utvrditi utjecaj primjene bistrila, bentonita na bazi natrija u koncentracijama od 50 i 100 g/hl u različitim terminima aplikacije, odnosno izravnom aplikacijom u mošt te u 2/3 fermentacije zbog pretpostavke da će različite količine bentonita aplicirane u dva različita termina utjecati na osnovni fizikalno-kemijski sastav, koncentracije ukupnih proteina te proteinsku stabilnost vina. Istraživanje čiji su rezultati pokazali značajne razlike u intenzitetu, tonalitetu i pigmentu boje, ukupnom sadržaju fenola i proteina te proteinskoj stabilnosti u odnosu na kontrolni uzorak ne tretiran bentonitom provedena su na sorti ´Malvazija istarska´ iz vinograda na području Radeki polja.In viticulture and wine production high temperatures have recently become the most common problem especially during the ripening period which can often have an effect on intensive protein accumulation in grapes. This impairs the wine quality inside the bottle due to the appearance of percipitate and turbidity as a result of denaturation of unstable forms of protein. Therefore, the aim of this study was to determine the effect of betonite, sodium-based clay, in concentrations of 50 and 100 g/hl during different application periods that were applied directly to the must and at 2/3 of the fermentation with the assumption that different amounts of bentonite will have different impact on physico-chemical composition, total proteins concentrations and protein stability. The research results showed significant differences considering intensity, tonality, pigment color, total phenol and protein content and protein stability in relation to the control sample where bentonite application was omitted. The research was conducted on the Malvazija istarska variety within vineyards in Radeki polje