Research Of The Change Rule Of The Content Of Resveratrol And Its Derivatives In Muscat Grape Under UV-C Irradiation

Muscat grape is the grape that can be ate directly or used to made wine.It contains rich of Resveratrol and its derivatives,which have health functions such as antioxidant,protect liver and so on.Tianjin Chadian Muscat grape was studied in this paper.And the purpose of this paper was to study on influence of the UV-C irradiation on the content of resveratrol and its derivatives in Tianjin Chadian Muscat grape.This paper established a HPLC-MS/MS detection method,optimized the extraction conditions,and compared and analyzed the influence of irradiation dose storage time and storage temperature on the content of resveratrol and its derivatives in Muscat grape and the enzymes activity of resveratrol related enzymes.After optimizing,this paper determined to the HPLC-MS/MS detection method with a Thermo Golden column(4.6×250 mm,5.0 ?m)with the mobile phase consisting of 0.1%(v:v)formic acid water-methanol(20:80),the flow rate was 0.5 mL·min-1,the injection volume was 10 ?L,and the column temperature was 30?;Multiple reaction monitoring(MRM)was measured in negative icon mode.The correlation coefficients of linear calibration curves were over 0.999 in the corresponding concentration range.The limit of quantification was low,and the precision was high.The average recoveries of the Res,PD and PS ranged from 85.61% to 99.03% that fit in with experimental requirements.Combined with the single factor test results,response surface methodology(RSM)was applied to optimize the extraction conditions.And the total content of Resveratrol?Piceid and Pterostilbene was used as the investigation index.A maximum extraction rate was achieved.The optimal extraction conditions were used Ethyl acetate as solvent,temperature of 57?,extraction time of 32 min,and solid to liquid ratio 1:15 g/mL.Under the optimal extraction conditions,the predicted value of stilbenes in Muscat Grape was105.30 ?g/g,and the actual value was 104.97 ?g/g.Moreover,the relative error of the established model for extraction efficiency was 0.31% compared to the predicted value.The maximum extraction rate was appropriate for the extraction of stilbenes in Muscat Grape.The irradiation dose,storage time and storage temperature were the main factors which have impact on the content of resveratrol and its derivatives in Muscat grape.After radiated by 3.0 kJ/m~2 or 4.5 kJ/m~2 of UV-C,Muscat grape quality declines can be restrained effectively,and achieved the purpose of keeping fresh.The Muscat grape was detected immediately after irradiated,the results showed that the content of Res was two and a half times as the control group,when the irradiation dose was 3.0 kJ/m~2;the content of PD was four times as the control group;and PS was not detected.When the Muscat grape was stored under 4? after radiated by 4.5 kJ/m~2 of UV-C,the content of Res and PD became tothe maximum within 48 h,the content of PS became to the maximum within 72 h.When the Muscat grape was stored under 0?,4? and indoor temperature after radiated by 4.5kJ/m~2 of UV-C,the result showed that the content of Res and PD became to the 90.29 ?g/g and 163.28 ?g/g within 48 h under indoor temperature,and the content of PS became to the46.19 ?g/g within 72 h under indoor temperature.The synthesis and metabolism of resveratrol and its derivatives related to the enzyme activity of resveratrol related enzymes.The enzymes activity of PAL and ?-glucosidase became to the maximum after radiated by 4.5 kJ/m~2 of UV-C,and the POD and PPO after radiated by 6.0 kJ/m~2 of UV-C,when the Muscat grape was detected immediately after irradiated.When the Muscat grape was stored under 4? after radiated by 4.5 kJ/m~2 of UV-C,the enzymes activity of ?-glucosidase became to the maximum within 24 h,the PAL within 48 h,and the POD and PPO within 96 h.Compared with different storage temperate,the enzyme activity of PAL,?-glucosidase,POD and PPO could reach the maximum value15.3 U/gFW?69.5 U/gFW?13.3 U/gFW?2.2 U/gFW,under indoor temperate.By contrast with the content of Resveratrol and its derivatives in the Muscat grape,the enzyme activity of PAL and ?-glucosidase change trend was similar to the contents of Res and PD change trend;the enzyme activity POD and PPO change trend was similar to the contents of PS change trend.Enzymatic activity can influence the synthesis and metabolism of Res.