Influence of membrane filtration on the chemical composition and quality of Graševina wine sort

Zadatak rada bio je ispitati utjecaj membranske filtracije na kvalitetu i kemijski sastav vina sorte graševina. Vino je filtrirano na pilot membranskom filteru koji je opremljen sa jednim cijevnim keramičkim modulom sa keramičkom membranom. Membrane su tipa SCT Membralox. Mjeren je protok permeata na početku filtracije, na kraju filtracije te ukupni permeat. Određen je sastav filtriranog vina standardnim metodama, te prema kemijskom sastavu je vino svrstano u određenu skupinu kvalitete. Tijekom filtracije vina zbog povećanja koncentracije čestica mutnoće i zbog povećanja polarizacije koncentracije dolazi do smanjenja protoka permeata. Nakon membranske filtracije, antioksidacijska aktivnost vina se nije promjenila, udio slobodnog i ukupnog SO2 se smanjio, te je postignuta visoka bistroća vina i poboljšana boja vina. Udio ostalih važnih sastojaka – alkohola, ekstrakta bez šećera, ukupnih kiselina, fenola, flavonoida i pepela se vrlo malo smanjio, tako da je vino zadržalo visoku kakvoću i ostalo u kategoriji kakvoće vrhunsko vino. Na osnovi rezultata istraživanja provedenih u ovom radu može se zaključiti da je membranska filtracija dobar postupak filtracije vina jer ne uzrokuje značajnu promjenu kemijskog sastava i kakvoće vina.The aim of this work was to estimate the influence of membrane filtration on the quality and the chemical composition of the wine sort graševina. The wine was filtered on a pilot membrane filter which was equipped with a tubular ceramic module with a ceramic membrane. The type of membranes was SCT Membralox. The permeate flow was measured at the beginning of filtration, at the end of filtration and total permeate was measured as well. The composition of the filtered wine was determined by standard methods and classified into a particular quality group according to the chemical composition of the wine. During the wine filtration, there was a decrease of the permeate flow due to increase in particle concentration turbidity and polarization concentration. After membrane filtration, the antioxidant activity of wine did not change; the proportion of free and total SO2 decreased, and high limpidity of wine was achieved and color of wine was improved. The proportion of other important ingredients, alcohol, extract without sugar, total acids, phenols, flavonoids and ash was reduced to a small extent, so the wine kept its high quality and remained in the category of premium quality wine. Based on the results of this study, it can be concluded that membrane filtration is a good wine filtration process because it does not cause a significant change in chemical composition and wine quality