Effects Of S-adenosyl-L-methionine On Three Fungicide Residues In Cabernet Sauvignon Berries And Wine

At present,the wine industry has become one of the emerging industries in Xinjiang.However,grapes(Vitis vinifera L.)often suffer from diseases during planting.Chemical fungicides are often used to prevent and treat diseases,which brings hidden dangers to wine quality and safety.Pesticide residues,on the one hand,may cause damage to consumers' health,and on the other hand,they may also affect wine quality.In order to improve the safety of wine and reduce the effect of pesticides on wine quality,this paper uses"Cabernet Sauvignon" grapes as a test material to study the effects of S-adenosyl-L-methionine(SAM)on three types of wine.Control effect of broad-spectrum fungicides Azoxystrobin(AZX),Metalaxyl(Me),and Thiophanate-Methyl(TM),physiological mechanisms that promote pesticide degradation,and their effects on grapes and wine quality,in order to provide theoretical reference for the research of SAM control pesticide residues.The main findings are as follows:(1)The effect of SAM treatment on the content and quality of three fungicides in grape fruits was explored.The results show that 1.0 ?mol·L-1 SAM spray treatment can significantly reduce the content of AZX and TM in grape fruits,and reduce the content of Me to a certain extent,indicating that SAM can accelerate the degradation process of pesticides in grape fruits,according to the type of pesticide;SAM spray treatment can promote the accumulation of soluble solids,reducing sugars,total phenol,and anthocyanin in grape fruits and reduce the titratable acid and tannin content,indicating that SAM treatment can effectively improve grape quality and promote fruit is ripe.(2)The effect of SAM treatment on active oxygen metabolism of grape fruit was explored.The results show that spray treatment of 1.0 ?mol·L-1 SAM can effectively increase the production rate of superoxide anion(O2-·)and the content of hydrogen peroxide(H2O2)in the early stage of grape fruit treatment after applying pesticide AZX,which is effective promote the oxidative degradation of pesticide AZX in grapes,and enhance the safety of grape fruit consumption.SAM can effectively increase the activity of Superoxidase(SOD),catalase(CAT),peroxidase(POD)and ascorbate peroxidase(APX),ascorbic acid(AsA)content,and effectively reduce the accumulation of malondialdehyde(MDA)under pesticide stress has enhanced the resistance of fruits and vegetables.This indicates that SAM treatment promotes the degradation of grape fruit pesticides and enhances the tolerance of grapes to pesticide stress,which is closely related to the regulation of reactive oxygen species(ROS)metabolism.(3)The effect of SAM treatment on the glutathione-related detoxification system of grape fruit was explored.The results show that spray treatment with 1.0 ?mol·L-1 SAM can effectively improve grape fruit reduced glutathione(GSH),oxidized glutathione(GSSG)and total glutathione(Total glutathione,GSH+GSSG)content,increase glutathione reduction oxidation ratio(GSH/GSSG),enhance glutathione reductase(Glutathione reductase,GR)and glutathione peroxide enzyme(Glutathione peroxidase,GPX)activity induces enhanced levels of glutathione metabolism.At the same time,the activities of glutathione S-transferase(GST),the key enzymes for understanding the toxicity,were improved,and the enzyme-mediated degradation of pesticides in plants was accelerated.This shows that SAM treatment promotes the degradation of plant pesticides and is closely related to the regulation of glutathione-related detoxification pathway metabolism.(4)The effect of SAM treatment on the content and quality of three fungicides in wine was explored.The results show that 1.0 ?mol·L-1 SAM spray treatment can significantly reduce the content of AZX,TM and Me in wine,indicating that SAM can effectively control the pesticide residues in wine;SAM effectively increased the alcohol content,total phenol,total anthocyanin content,chroma,and compliance index of the wine,and effectively reduced the total acid content of the wine,which had less effect on the tannin content.The sensory evaluation found that the SAM treatment improved the color quality,aftertaste and balance of the wine,but the aroma intensity decreased slightly,which improved the sensory quality of the wine as a whole.It shows that the SAM treatment can effectively reduce the pesticide residues in wine and improve the wine quality to a certain extent.Pesticide residues in the wine making process have been greatly reduced(about 80%).Alcohol fermentation(AF)and clarification process have obvious effect of removing pesticides,and malolactic fermentation(MLF)and aging stage have slower reduction of pesticide content.From the results of the above studies,it can be known that the external application of 1.0 ?mol·L-1 SAM spray treatment can effectively improve the quality of grapes and wine.In addition,SAM can effectively reduce AZX,Me,and TM pesticide residues in grapes and wines by inducing grape fruit ROS and glutathione-related detoxification metabolic processes,and improve the quality of grapes wine and food safety.