The Effect Of Controlled Atmosphere Storage On The Quality And Ethylene Synthesis Of Kiwifruit

In this experiment,the effects of controlled atmosphere storage on quality of storage and shelf life and ethylene synthesis in Actinidia deliciosa(’Yate’,’Xuxiang’,’Jinxiang’and ’Hayward’)were studied.The experimental arrangments were three controlled atmosphere treatments(at 0 ± 0.5℃,CA1:2.5～3%O2+3.5～4.0%CO2;CA2:2.5～3%O2+4.0～4.5%C02;CA3:2.5～3%02+4.5～5.0%CO2,respectively),0.5 μl/L 1-MCP treatment and cold storage as control.The results were as follows:1.Compared with control,controlled atmosphere storage effectively delaied thesoftening of ’Yate’ kiwifruit,CA2 inhibited fruit softening better than CA1 and CA3 in previous 70 days,there was an extremely significant difference between CA2 and CA1,CA3.Up to 140 days,there were significant differences between control and CA.treatments,but all CA treatments had no distinct differences.Compared with control,CA2 and CA3 had no significant inhibitions on the rise of soluble solids content.During the previous 85 days,soluble solids content of CA1 rose more slowly than control,CA2,and CA3.Up to 140 days,there were no significant differences between control and all CA treatments.Therefore,the optimal parameter of CA for ’Yate’kiwifruit storage is CA2(0±0.5℃,2.5～3%02 + 4.0～4.5%C02).2.Compared with control,controlled atmosphere storage effectively delaied the kiwifruit softening of ’Xuxiang’ kiwifruit throughout the storage time.There were significantly different between controlled atmosphere treatments and control(P<0.05)throughout the storage time.CA1 and CA2 were better than CA3 in maintaining firmness;CA1 and CA2 had no significant difference,CA1 and CA2 were good for in delaying softening of kiwifruit.Up to 140 days,there was significantly different between CA1 and control(P<0.05),but CA2,CA3 and control had no significant differences;Therefore,the optimal parameter of CA for ’Xuxiang’ kiwifruit storage was CA2(0 ±0.5℃,205～3%02 + 4.0～4.5%CO2).3.There were significantly different between CA treatments and control(P<0.05)throughout the storage time,especially CA3.Compared with control,CA treatments can inhibit the rise of soluble solids content throughout the storage period,especially CA2Up to 130 days,there was significantly different between control and CA1,CA2(P<0.05),no significant differences with CA3.Therefore,the optimal parameter of controlled atmosphere for ’Jinxiang’ kiwifruit storage was CA3(0 ± 0.5 ℃,2.5～3%O2 +4.5～5.0CO2).4.It occurred significant differences(P<0.05)between CA treatments and control in ’Hayward’ kiwifruit,CA3 had the best effect on maintaining firmness.Each controlled atmosphere had a certain inhibition on the increase of soluble solids content.Moreover,the soluble solids content of CA2 rose more slowly than that of control,CA1 and CA3.Up to 140 days,there were remarkable differences(P<0.05)between CA treatments and control.Hence,the optimal parameter of CA for ’Hayward’,kiwifruit storage is CA3(0 ± 0.5℃,2.5～3%O2+4.5～5.0%CO2).5.CA could effectively maintain the firmness of four cultivars of kiwifruit during storage,and the fruit rapidly softened to be edible through shelf life.However,CA had no significant effect on the soluble solids content.Compared with CA,0.5 μl/L 1-MCP treatment didn’t markedly influenced the decrease of firmness during storage,while it delayed the softening of kiwifruit during shelf life.6.Compared with control,CA significantly inhibited ethylene biosynthesis in kiwifruit.The time and peak values of ethylene production were different in different cultivars.The peak of ethylene production in ’Yate’,’Xuxiang’,’Jinxiang’ and’Hayward’kiwifruits appeared at 85,85,62 and 120 days during cold storage,respectively.The appearing process of ethylene production peak also accompanied with the rapid softening of kiwifruit.Therefore,’Hayward’ had stronger storability than’Yate’,’Xuxiang’and ’Jinxiang’.7.Compared with control,CA dramaticlly inhibited the accumulation of ACC content,the ACC synthase and ACC oxidase activities of ’Yate’ kiwifruit.And they showed a downward trend after rising first.Moreover,their peak values appeared at 85 days during cold storage,consistent with the time when ethylene production peak value appeared.Molecular biology researches showed that CA significantly inhibited the expression of ACS1 and ACO1 genes which related to mature.’Xuxiang’ kiwifruit also illusteated the same result.8.High CO2 treatment made ’Hayward’ kiwifruit occur poisoning symptoms and it’s injury mainly showed that treated fruit flesh changed to yellowish-brown and the core hardened.What’s more,flesh elasticity enhanced and had no indentation after being pinched.In addition,the symptoms appeared in the epicarp primarily and expanded to axile gradually.