Impact of SO2 and bentonite addition during fermentation on volatile profile of two varietal white wines

Abstract

To understand the impact of SO₂ and ascorbic acid (AA) in must fermentation, Arinto and Síria musts were fermented under the same conditions, but in the presence of different doses of SO₂ and with or without bentonite addition. Arinto was fermented with 0, 50, 100 mg/L of SO₂ and 100 mg/L of AA. Síria was fermented with 0, 15, 30, 45 mg/L of SO₂ and 100 mg/L of AA. The volatile organic compounds (VOCs) were analysed by HS-SPME-GC/MS.

Based on PCA results obtained from VOCs profiles for both varieties, first and second principal components were responsible for more than 60% of the respective system's variance. In both wines, the presence or absence of bentonite was clearly discriminated. This work also shows that depending on the different doses of SO₂ used, the resulting VOC profiles clearly discriminate these different fermentation conditions. The use of AA in both varieties resulted in a different VOC profile compared to the use of SO₂. From this study it was also possible to verify from the VOCs profile, that Arinto wine is less resilient to fermentation changes then Síria wine, which may impact technological choices.