| Moderate consumption of wines containing resveratrol has been linked to the reduction of serum cholesterol levels. The standard addition method used in combination with the selected HPLC procedure yielded no significant differences between the calculated resveratrol levels of samples of Cabernet Sauvignon, Cynthiana, and Noble wines. Since sample preparation was avoided for HPLC analysis, this procedure would be useful in laboratories that do not have advanced analytical equipment, such as GC-MS.;Variety, UV light exposure, enzyme addition, skin contact time, and the fining agents, carbon and PVPP, affected the resveratrol levels of wines from the white varieties, Chardonnay and Chardonel, and the red varieties, Cabernet Sauvignon, Cynthiana, and Noble. UV light exposure of the grape clusters significantly increased the resveratrol level of Cynthiana and Noble wine produced in 1994, but did not yield a constant result in the other experiments from 1995 and 1996 wines. Enzyme addition significantly increased resveratrol levels in Chardonnay wine but not Chardonel wine. Skin contact time influenced the extraction of resveratrol from the skin in the red varieties, but maximum extraction time was dependent on variety of the grapes. Carbon addition decreased the resveratrol level of Noble wine but not Cynthiana in 1994 wines. The addition of PVPP significantly lowered resveratrol level in Chardonel, Chardonnay, Cabernet Sauvignon, Cynthiana, and Noble wine. However, low levels of PVPP addition can be used without causing significant removal of resveratrol.;Type of fining agent and fining agent level negatively affected resveratrol levels in all wines and resulted in various regression trends. In Study 1, for all fining agents the addition of recommended maximum levels of agent significantly lowered resveratrol levels as compared to control. However, the addition of fining agents at Level 0 was significantly higher than Level 3, but Level 0 was not significantly different from Level 1. In Study 2, the effect of carbon fining differed according to variety, with the least removal of resveratrol in Cabernet Sauvignon and the most removal in Cynthiana and Noble. The resveratrol levels of the control wine were significantly higher than the levels of wine fined with the recommended maximum amount of agent, for all varieties. The effect of fining agent was further influenced by the variety of wine selected for analysis. We conclude that low levels of fining agents can be used without the significant loss of resveratrol.;UV irradiation of the grapes increased resveratrol levels of the wine produced. UV exposure of Cabernet Sauvignon and Noble grapes resulted in a linear trend, but UV exposure of Cynthiana grapes yielded a quadratic trend. Increases in resveratrol in grapes result in corresponding increases in wines made from those grapes. Resveratrol increased with increasing UV exposure time in all varieties. (Abstract shortened by UMI.). |
