Effects Of Exogenous Methyl Jasmonate On Monoterpenes And ?-Glucosidase In Cabernet Gernischt Grapes

The most abundant monoterpene aroma substances in wine grapes are often used as characteristic compounds for the aroma of grape and wine varieties.In this study,we used the exogenous jasmonate to induce the fruit of Cabernet Gernischt,and then studied the triterpene compounds in the grape fruit and wine by HS-SPME/GC-MS method to clarify the effect of exogenous jasmonic acid ester on the grape wine and wine monoterpene compounds,the use of foreign inducers to improve the sensory quality of grapes and wine to provide the theoretical basis and technical support.The main findings are as follows:1.Three different extraction methods were carried out by comparing liquid-liquid extraction(LLE),solid phase extraction(SPE)and headspace-solid phase microextraction(HPSPME),and GC-MS were used to simulate four kinds of single.The average RSD value of the method was 0.65 % and the detection limit was 0.12-0.62 ?g/L,the recovery rate was 92.6 ~ 99.3 %,And optimize the method parameters.The optimum conditions for the establishment of a 20 m L sample vial were added with 10 m L of wine,saturated with sodium chloride,magnetically stirred rotor and 50 ?L of the internal standard 2-octanol,polytetrafluoroethylene /silicone septum seal for DVB/CAR/PDMS fiber extractor was extracted at 60°C for 30 minutes.2.The grape fruits were treated with different concentrations of Me JA,and it was found that the content and variety of monoterpenes increased with the increase of concentration.0.5 mmol/L and Me JA treatments had little effect on the content of monoterpene compounds in grape,and other concentrations could increase the content of monoterpene compounds in grape.The effects of 15 and 20 mmol/L were the most obvious.The final 15 mmol/L was the best concentration.Compared with the control group,the content of monoterpenes was 824.67 ?g/L,and the number of monoterpenes was 16.The control group monoterpene content was 226.26 ?g/L,and there were 12 kinds of monoterpene compounds.3.The effects of Me JA spraying on the activity of ?-glucosidase in the fruit were studied.The results showed that the enzyme activity was the highest at 15 mmol/L Me JA treatment in the same sampling time and in different concentration groups.4.After the fermentation of different concentrations of Me JA,the contents and types of monoterpenoids in alcohol samples increased.Compared with the control group,the content of monoterpene was 842.93 ?g/L and 16 species of monoterpene were 15.00 mmol/LMe JA.The content of monoterpenoids in the control group was 342.58 ?g/L,There are 6 kinds of compounds.It was suggested that the concentration of Me JA could promote the ?-glucosidase in the fruit of Cabernet Gernischt,which was beneficial to the transformation and release of the bound aroma in the fruit of the grape.In summary,the foliar spraying of methyl jasmonate can promote the content and species of monoterpenoids in grapes and wines,and the foliage spraying Me JA promotes the activity of ?-glucosidase in grape fruit.Which is beneficial to the transformation and release of the bound aroma substances in the fruit of the grape,and has a positive effect on the release of the aroma of the grape and wine varieties.