Effect of variety, ultraviolet light exposure, and enological methods on the trans-resveratrol level of wine

Resveratrol is one of the wine components related to moderate wine consumpt ion and reduction of serum cholesterol levels. The standard addition method was used with a high pressure liquid chromatography procedure to calculate resveratrol levels. Grape variety, UV light exposure, enzyme addition, ski n contact time, and the fining agents, carbon and PVPP, affected the resver atrol levels of wines from the white varieties, Chardonnay and Chardonel, a nd the red varieties, Cabernet Sauvignon, Cynthiana, and Noble. UV light ex posure of the grape clusters significantly increased the resveratrol level in Cynthiana and Noble wine produced in 1994, but did not yield a consisten t result in the other experiments from the 1995 and 1996 wines. Enzyme addi tion 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 the maximum extraction time was dep endent on the variety of the grapes. Carbon addition decreased the resverat rol level in Noble wine but not in Cynthiana in the 1994 wines. The additio n of PVPP significantly lowered resveratrol level in Chardonel, Chardonnay, Cabernet Sauvignon, Cynthiana, and Noble wine. However, low levels of adde d PVPP addition did not cause significant loss of resveratrol.