Studies On Change Trend Of Resveratrol In Dry Red Wine

The translation equations from trans-resveratrol(piceid) to cis-resveratrol(piceid) are established: y=0.05x+19.137, y=0.2219x+3.7006.HPLC was established to determine the quantity of resveratrol in wine, the chromatographic separating conditions is: mobile phase A is water adjusted pH to 2.4 with phosphoric acid, mobile phase B is 20% acetonitrile. First 82% A and 18% B is kept 10 minutes, then 77% A and 23% B is kept for 5 minutes, then with 75% A and 25% B is kept for 5 minutes, 68% A and 32% B is kept for 10 minutes, finally 100% A is kept for 5 minutes. Mobile rate is 1mL/min, column temperature is 25°C, detecting wavelength is 306nm, injecting volume is 20uL.The relative standard diviations range from 1.2% to 3.9%, the recovery rates are 95.5%-103.5%. The accuracy of the method is proved.Samples taken from shacheng, chagnli, jixian, ningxia in 03, 04,05 indicate:1. The quantity of resveratrol in grape is very low ( not achieved 1mg/L) , it is rising in main fermentation then falling in MLF, finally retains steady.2. In different years, the quantity of resveratrol is different too, even the same place or kind, 05 is the highest year. The different climates lead to different results.3. Quantities are 6.68mg/L, 6.90mg/L ,7.24mg/L in shacheng basement in 2005, and 6mg/L in factory, basement has more quantity than factory, for, also grape' variety is same but the quality is different, good grape always makes good wine.4. Compared to Cabernet Sauvignon, wine brewaged with Merlot has more resveratrol, for example, wine brewaged with Merlot achieves 13.41mg/L and brewaged with Cabernet Sauvignon just is 2.5mg/L, so grape' variety has a very important infection on resveratrol.Cabernet Sauvignon was used to make tests, three kinds of yeasts and two kinds of enzymes are included. The results indicate:1. When quantity added is same, the Must added the 2^nd enzyme(the 1^st enzyme mixed with Ultraflol) has more resveratrol than the Must added only the 1^st, that is to say, the Ultraflol enzyme could increase the quantity, because resveratrol has polymer in wine, Ultraflol releases the monocase.2. The quantity of resveratrol is rising in main fermentation, and keeps rising in beginning of MFL ,but then falling, adding SO₂ during MFL would decrease the loss, because SO₂ could prevent it oxidation.