Effect Of Ozone Treatment On Postharvest Quality And Disease Resistance Of Melon Fruit

Melon is a kind of fruit with rich resources and excellent quality in Xinjiang.It plays a majo r role in horticultural crops and is deeply loved by consumers.However,melons are susceptible to pathogenic bacteria during storage and resulting in significant losses.The antibacterial and fresh ke eping characteristics of ozone have been confirmed in many kinds of fruits and vegetables,but the re is less research on melon preservation mechanism.There are fewer ways to combine treatment t imes and treatment concentrations at different intervals.Melons are treated with ozoneat different i ntervals and concentrations.Optimum ozone treatment through inhibition of pathogenicbacteria and melon quality changes.To study the effects of ozone on the quality of muskmelon,disease resista nce and antioxidant enzymesand activity.These studies can provide a theoretical basis for ozone a pplication in melon preservation.The research contents are as follows:1.“Xizhoumi No.17”was carried out at 6～8℃with RH 80～85%.To study the treatment of melon by different ozone concentration and interval time（2.14、4.28、6.42 mg/cm³,12、24、48 h）.And the melon sealed for 40 min after ozone treatmentand.To study the dynamic changes of rele vant quality indexes of melon during the 42 d storage period and the antibacterial on A.alternata and Fusarium through appropriate ozone treatment.The experiment shows:Ozone treatment can eff ectively delay the rise of relative conductivity.Ozone significantly inhibited the decline insugar con tent,hardness,TA,V_C and they decreased by an average of only 0.07%,0.03%,1.10%,1.20%pe r day.At the same time,ozone reduced the rate of weightlessness by 42%and respiratory rate by23%,delayed respiratory peaks by 7 days.And the decay index was only 6.8%of the control gr oup.It has a strong antibacterial effect on F.semitectum and A.alternata.It has a better antibacteri al effect on A.alternata.A.lternaria grows an average of only 4.04 mm perday.Ozone concentra tion of 2.14 mg/cm³ and the interval of 24 h can best guarantee the quality and extend the low t emperature storage time of melon fruit,which provides a feasible method for the storage,transport ation and preservation of melon.2.“Xizhoumi No.25”was carried out at 6～8℃with RH 80～85%.To study the quality and physiology of melon fruits were inoculated with A.alternata on optimum ozone（4.28 mg/cm³,△t24h）treatment.The experiment shows:Ozone treatment inhibited the decline of peel hardness,fru it hardness,weight loss rate,TSS content and Vccontent.It slows down the incidence of 100%by10 days.It not only inhibited the peaks of respiratory rate and ethylene release,but also delayed t he peak time.3.“Xizhoumi No.25”was inoculated with A.alternata in the same environment.The effect on the MDA,H₂O₂content,O₂^-·production rate and activities of antioxidant enzymes（POD,SOD,CAT,APX）of melon were inoculated by ozone.The experiment shows:Ozone treatment inhibits the increase of H₂O₂,MDA content and O₂^-·production rate.It increased the activity of antioxidant related enzymes and postponed the peak of 5 days.It also has the effect of storage and preservation atthe end of storage.4.“Xizhoumi No.25”was inoculated with A.alternata in the same environment.The effect on the diameter of lesions,depth of lesions,activity of enzymes（PAL,CHT,GLU）and the producti onof disease resistant substancesof melon were inoculated by ozone.The experiment shows:Ozone treatment inhibits the increase in lesion diameter and lesion depth.It not only increased the activi tyof disease-resistance-related enzymes,but also delayed the peak of 5～10 d.It also promotes the production of total phenols,flavonoids and lignin.