engleski

Effect of synthetic polymers on white wine stabilization

One of the main problems with white wine is stability, especially during its storage in the bottle. It is known that the many factors, in specific conditions, may have a negative influence on wine colour, flavour or appearance. Among of these factors are polyphenols (the oxidizable matter), oxygen (the initiator of oxidation process) and certain metal ions, such as Fe, Cu, Zn and Mn (activators of the process). One of the methods of colour stabilization of wine is based on removal of polyphenols using a synthetic polymer - polyvinylpolypyrrolidone (PVPP). Polyvinylimidazole (PVI) is a synthetic polymer too, but its application in fining is removal of metal ions from wines. Structure of PVI is based on the structure of the PVPP, where the vinylpirrolidone is partially substituted by vinylimidazole, as active side for metal ions. The goal of this work was to compare the possibility of polyphenol and metal removal using PVPP and PVI as fining agents. Fining of white wine was done in industrial conditions, using 0, 4 g/L of polymers. Fining with PVPP resulted by significant decreasing quantity of colour, total phenols, leucoanthocyanins and Cu. Results after fining by PVI showed significant decreasing quantity of metal ions (Cu, Fe, Zn, Al but not Mn, Na, K, Ca, Mg, Sn and Pb). Colour and polyphenol characteristics were decreased too but in smaller quantity than in experiments where PVPP was used.

polyvinylimidazole; polyvinylpolypirrolidone; stabilization; white wine

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