A new enzymatic solution for prevention of quercetin precipitation in red wines

Ensuring wine quality is crucial. However, the rise in quercetin deposits in red wines, particularly those made from Sangiovese grapes, is escalating due to factors such as machine harvesting and climate change (Price et al., 1995; Blancquaert et al., 2019; Gambuti et al., 2020; Vendramin et al., 2022). This issue extends beyond mere visual inconveniences linked to bottled wine to concerns about potential organoleptic damage. Currently used methods, such as PVPP fining, are prohibited in organic wine production under EU regulation n. 203/2012. To address this issue, the present study explored an organic-friendly solution that involves the use of a pectolytic enzyme with secondary glycosidase activity. The enzyme was validated in Chianti wine production and was observed to significantly accelerate the hydrolysis of glycosylated quercetins, giving their aglycone form. This accelerated process enhanced deposition before bottling without causing significant wine colour depletion, thus can be considered a promising approach even for organic winemakers.