To date, the project has completed two goals, and is making progress on two others. We have analyzed the thermodynamics and kinetics for the sulfur dioxide binding of four different aldehydes and ketones, the major binders of SO2. This was carried out using a totally new approach, NMR spectroscopy, which allowed us to analyze the reactions under wine-like conditions. Two-dimensional (1H-1H) homonuclear and heteronuclear (13C-1H) single quantum correlations (COSY and HSQC) nuclear magnetic resonance experiments of wine samples were used for the simultaneous identification and quantification of free and, for the first time, sulfite bound acetaldehyde, pyruvic acid, acetoin, methylglyoxal and α-ketoglutaric acid. This new technological approach opens the door to possible new approaches to measuring free and bound sulfur dioxide. The effect of varying levels of SO2 and glutathione on micro-oxygenation was also investigated and it was surprising to see that both antioxidants suppress oxygen consumption. The cause for this effect may be related to suppression of the free radical formation by the Fenton reaction. When wines were depleted of these antioxidants, it appears that the formation of aldehydes rapidly increased, along with the formation of stabilized pigments. A new method to analyze glutathione, a possible new antioxidant for protecting wine, is also underway.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF2013-10-15 12:29:172017-10-15 12:30:29Oxidation of Wine: Control for Quality?Understanding Effective Sulfur Dioxide and the Role of Glutathione