FACTORS AFFECTING QUERCETIN SOLUBILITY IN SANGIOVESE RED WINE: FIRST RESULTS
Quercetin (Q) is present in grape in form of glycosides and as aglycone. These compounds are extracted from grape skins during winemaking. In wines, following the hydrolysis reactions, the amount of quercetin aglycon can exceed its solubility value. Unfortunately, a threshold solubility concentration for quercetin in wine is not easy to determine because it depends on wine matrix (Gambuti et al., 2020).
This study is aimed at evaluating factors affecting the solubility of Q in red wine. The role of anthocyanins and mannoproteins (MPs) was evaluated. The role of anthocyanins in Q solubility was evaluated by adding known amount of grape derived anthocyanins to a model solution containing 30 mg/L of quercetin. Data showed that the solubility of Q increased by increasing the amount of grape derived anthocyanins in model solution until a complete dissolution of 30 mg/L of Q when 740,8903 ± 17,069 mg//l of anthocyanins were added. This is likely due to the π-π interactions between anthocyanins and Q determining the formation of stable copigmentation complexes in red wine (Whaterhouse 2016). In a further experiment the addition of two different mannoproteins to a model solution containing 30 mg/L of quercetin and grape derived anthocyanins was also tested in controlled conditions. A slight positive effect of MPs on quercetin solubility (until the twelve % of value detected in control samples) was observed. It is therefore likely that group of compounds tested are involved in Q colloidal stability.
Issue: OENO Macrowine 2023
1. Department of Agricultural Sciences, Section of Vine and Wine Sciences, University of Napoli ⟨Federico II⟨, Viale Italia, Avellino 83100, Italy
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Quercetin, solubility, wine, anthocyanins, mannoproteins