Abstract: In the study, we investigated the effect of addition of five different clarifying agents: soy protein, gelatin, bentonite, casein and polyvinylpolypyrrolidone (PVPP) after natural clarification of sparkling base wine (Chardonnay) on its clarity, physicochemical parameters, flavor compounds and sensory quality. The results showed that the clarification treatments could significantly increase the transmittance and decrease the color intensity of wine (P < 0.05). While alcohol content in the treated wine was not significantly changed, volatile acids, total acid, residual?sugar and total phenols were decreased by 0.18–0.30, 0–0.09, 0.25–1.20 and 0.05–0.21 g/L, respectively. No significant differences in the contents of total acids, volatile acids and total phenols were found among all the treatments except that bentonite and casein had a greater effect on total sugar content. In addition, the types and amounts of aroma components in the wine samples were decreased after clarification. However the amount of volatile compounds in the wine treated with soy protein was obviously higher than in other groups, which was testified by principal component analysis. The wine treated with soy proteins at 200 mg/L exhibited good visual appearance and aroma and its sensory evaluation score was closest to that of the control, indicating that soy protein, a new type of plant protein clarifying agent, can be used for the clarification of sparkling base wine.

Key words: sparkling wine, clarifying agent, clarification, volatile compounds, soy protein