Effect Of Postharvest Ultraviolet-C Treatment On The Fruit Quality And Expression Of Dfr Gene In Grape Berries

Grape polyphenol is a substance with a range of antioxidant capacity. It not only can resist ultraviolet radiation and ion toxicity, but also can affect organoleptic qualities of wine. The trail selects the grape berries (Cabernet Sauvignon) as experimental materials, and the materials were treated with Ultraviolet-C (UV-C)treatment. This paper expounds the effects of the grape berries’quality, especially the accumulation of flavanols and the expression of Dihydroflavonol 4-reductase (DFR) gene by UV-C treatment. The main results were as follows:1.Postharvest UV-C improve the quality of grape berries. UV-C treatment can improve the content of total soluble sugar and organic acid. The total soluble sugar content and organic acid content in UV-C treated fruit was significantly higher (P<0.0S) than CK at 30 minutes,60 minutes. UV-C treatment increase the content of vitamin C, but the difference is not significant at 5minutes.2.Postharvest UV-C obviously effect on the accumulation of grape polyphenols. UV-C treatment can increase total phenols and total flavonoids content. Anthocyanin content was found significantly higher (P<0.05) than CK at 5 minutes,10 minutes,30 minutes and 60 minutes. Flavan-3-ols were gained by accumulation and in 10 minutes,30 minutes difference(P<0.05) is remarkable. Flavanols content was increased significantly (P<0.05) than CK at 5 minutes,10 minutes,30 minutes,60 minutes.3.Postharvest UV-C treatment can reduce the damage of active oxygen to the grapes. It can obviously inhibit the accumulation of MDA content, induce SOD, CAT, POD enzyme activity increased, increase the content of GSH. Postharvest UV-C can improve the oxidation resistance of fruit. UV-C can increase the ability of clearing free radicals,such as DPPH · and ABTS·.4.The activity of DFR enzyme in the post-harvest grape berries was significantly increased by UV-C treatment. The significant difference(P<0.05) was found at 5 minutes,30 minutes,60 minutes.5.Postharvest UV-C treatment can induce the expression levels of dfr and significantly higher (P<0.05) than CK at 5 minutes.