The chemical and sensory evolution of a wine depends on the possible presence of oxygen and also on the nature and concentration of phenolic compounds, the temperature, the bissulfite concentration and on the initial physicochemical characteristics on the wine (pH, proteins, metal ions, etc). The oxidation of white wines and its consequences for color and aroma are considered as spoilage and must be avoided. The level of phenols in wines can be reduced by the use of gelatin, casein, activated carbon or various polymers such as polyvinylpolypyrrolidone (PVPP). The removal of phenolic compounds has a favorable effect on color and wine sensitivity to oxidation. The physical, chemical and sensory characteristics of the dry white wine Sauvignon blanc treated with PVPP, at concentrations of 0.5; 1.0 and 1.5g/l, were evaluated. The reduction in the total phenol and flavonoid levels, and also the decreasing in the color intensity, were directly proportional to the increase in the polymer concentration. The treatment with PVPP did not change the pH values and the total acidity of the samples. PVPP dosis above 0.5g/l had little influence in the remotion of 4-hydroxybenzoic and 4-hydroxy-3,5-methoxybenzoic acids. The use of 1.5g/l of PVPP removed significantly the 3,4-dihydroxybenzoic and 4-hydroxy-3,5-dimethoxybenzoic acids. In all concentrations, the polymer was very selective for 3,3',4',5,7 pentahydroxyflavanone (catechin). The results showed that the sensory characteristics of treated samples were similar to the sample without treatment, due to the low contents of total phenol and flavonoids.
white wine; polyvinylpolypyrrolidone; phenols; sensory analysis
