| Resveratrol (trans-3,4',5-trihydoystilbene) , as a phytoalexin, occurs in the berry skins of most grape cultivars and its synthesis is stimulated by the UV light, fungal infection and injury. It presents in red wine due to the fermentation with grape skin and seed. More and more researches prove that resveratrol has many beneficial effects on people health, such as reducing the risk of coronary heart disease (CHD), inhibiting platelets aggregation and low-density lipoproteins oxidation. In this research, the inducement of resveratrol with Ultraviolet(UV) and Salicylic acid (SA) in grape was studied and the change of resveratrol concentration during winemaking was analyzed. Base on the results obtained, some enological practices are suggested to be regulated in order to enhance the concentration of resveratrol in wine, so that the people can get more benefit from resveratrol via normal diet safely.Firstly, based on the published reports, a modified HPLC method for detection of four resveratrol isomers, including trans- and cis- resveratrol, trans- and cis- resveratrol glucosides, was established by using a PDA detecter. Three methods for extraction of resveratrol isomers from Muscat grape (after UV induce) skin were compared. The concentrations of fnms-resveratrol in the samples obtained by hot extraction and by RT extraction (Room Temperature) were 7.36 ug/g and 0.72 ug/g, respectively.The effects of UV and SA on the induction of resveratrol in Muscat and Cabemert Sauvignon were determined. According to concentration of resveratrol and the quality of grape (including sensory characters), the optimum time of UV exposure for the maximum resveratrol production was 300s (0.9KJ/m2) for Muscat (concentration of resveratrol rise to 11.13g/g) and 450s (1.35KJ/m2) for Cabemert Sauvignon (50.02g/g); the optimum concentration of SA treatment was 100mg/L for Muscat (65.42g/g) and 50mg/L for Cabemert Sauvignon (23g/g). Storage at low temperature (10 C) or under the sunlight after UV treatment restrained the synthesis of resveratrol in grape. However, the ray only has minor effect on resveratrol synthesis after SA inducement. In Muscat, the maximum concentrations of resveratrol is higher and last longer time than its in Cabemert Sauvignon. As we known, it is the first time to report the inducement of resveratrol by SA in grape.The total RNA was extracted from grapes skin (Cabemert Sauvignon) that had been treated by UV and SA, respectively. The Northern dot blot was performed using DNA fragments of sts and pal genes from grape as probes. Our results showed that the expression of sts and pal in grape skin was stimulated by UV and SA treatment. The expression of Pal gene strongly increased at 4-6h after the treatment with SA and at 6-24h after the treatment with UV. Sts expression increased at 1-2h after SA treatment and 1-6h after UV treatment It might indicate that the expression of sts gene was more sensitive than pal in grape skin upon the UV and SA application under our experimental conditions (Cabemert Sauvignon).Total Resveratrol, including four isomers, in red wine (Cabemert Sauvignon) get highest in the end of fermentation and decreased 15.7% in clarification subsequently. Under unsuitable storage condition, the resveratrol in wine might decrease greatly. The total content of resveratrol in wine could decrease 24.5% at high temperature(37 C) in darkness within 30 days. Opening for 4h, the loss of totalresveratrol in wine could be 18%, but it grew up to 38% after 8h.The wine made of Cabernert Sauvignon had more 30% total resveratrol than that made of Merlot. Using S.bayanus yeast was more efficient in total resveratrol accumulation than D254. Fermentation at 28 C took 32% more resveratrol than that at 25 C. Some new technology in winemaking, such as cross micro fluid membrane filtration (CMF) and rapid cold stabilization dynamic continous contact process were believed to fit wine filtration since they had only minor effect on the wine qualities and no effect on the total resveratrol.By UV and SA...
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