Effects Of Temperature And Ethylene Treatment On Fruit Quality Of 'Fuji' Apples

In recent years,with the improvement of living standards,people's requirements for fruit quality have become higher and higher.Postharvest is an important link to maintain and impr ove fruit quality.Therefore,postharvest treatment has become an important research field of f ruit quality control.In this experiment,we studied the effect of exogenous ethylene and tempe rature treatment on post-harvest quality of 'Fuji' apple,which was the largest apple variety 'Fu ji' in China.Especially in improving fruit aroma,the research results have laid a solid foundati on for the industrial application of temperature and ethylene in post-harvest quality assurance of 'Fuji' fruits.The main findings are as follows:1.With the increase of treatment days,the fruit hardness showed a downward trend unde r different treatment conditions.But within 8 d before treatment,Eth-32? treatment delayed t he fruit softening rate and maintained the fruit hardness.Compared with CK-4?,the hardnes s difference is small.2.The content of soluble solids in fruits was different in different treatments.The soluble solids content of fruits treated with Eth-32? and CK-32? increased first and then decreased with the increase of treatment time,and reached the peak at 6 d and 8 d respectively.Eth-32? had the highest soluble solid content on the 6th day.High-temperature ethylene treatment promoted the formation of soluble solids content within 6 days.3.The titratable acid content of the fruit showed a decreasing trend with the increase of tr eatment time.The effect of high temperature ethylene treatment on the change of the titratable acid content of Fuji fruit was small.4.After high temperature and ethylene treatment,the peak of fruit aroma release is advan ced,and the content of volatile substances increases.As the treatment time increases,the cont ent of esters increases and the content of aldehydes and ketones decreases.This is related to hi gh temperature and ethylene-induced aroma synthesis related enzyme activity LOX,ADH,A AT increased,up-regulated MdLOX1 a,MdADH3,MdAAT1 and other gene expression levels.The common aroma components of Fuji fruit detected under different treatments are ?-farnes ene,2-hexenal,2-methylhexyl butyrate,hexyl caproate,ethyl acetate,2-methyl butyric acid E thyl acetate,hexanal,ethyl butyrate,butyl acetate,butyl butyrate,hexyl acetate,2-methyl-1-butanol acetate,Z,E-?-farnesene,n-butanol,Hexanol,2-methyl-1-butanol,etc.Amon g them,the main fragrance-forming substances are butyl acetate,hexyl acetate,ethyl butyrate,ethyl 2-methylbutyrate,ethyl acetate,2-methyl-1-butanol,hexanol,and hexanal.We found th at after the 6th day of Eth-32 ? treatment,the fruit showed the highest aroma content,which was generally higher than other treatment groups.In addition,different temperature treatment s release their unique volatile substances,2-methyl hexanoate is a unique aromatic substance r eleased by fruits treated at 4 ?;2-methyl-2-methyl butyrate,caproic acid Propyl ester is a uni que aromatic substance released by fruits treated at 24 ?;hexyl butyrate,propanol,and ethan ol are unique aromatic substances released by fruits treated at 32 ?.