Effects Of Pre-treatments On The Storage Quality Of "Baldwin" Blueberry

Blueberries are not only rich in vitamins,anthocyanins,phenols and other physiological active ingredients,but also contains many amino acid,ascorbic acid,therefore it called "king of berries".For the reasons that the fruit is soft and succulency,and the plant respiration is vigorous,the self-life only have 2-4 d at room temperature(25 ?±5?),and 7?10 d under the condition of low temperature(2? ±2?)It restricted the baldwin blueberry industry development."Baldwin" blueberry is mature late,so is advantageous to realize the high yield of blueberry,for the positive momentum of baldwin blueberry plant development and broad market,the research of the effects of storage treatments is imminent.This paper mainly studies the different influences of blueberries 60Co ? gamma rays,chlorine dioxide(ClO2)solution soak,ozone(O3)treatment and pre-temperature treatment,chitosan treatment,heat treatment,hypobaric treatment and hypobaric treatment combined with ozone pre-treatment.By the way measures of the fruit decay rate,weight loss,colour aberration,total soluble solids(TSS),hardness,polyphenol oxidase(PPO),malondialdehyde(MDA),pectin enzyme(PG),cellulose enzyme(Cx),DPPH free radicals clearance,anthocyanins,and other indicators to research the different treatments on storage quality of blueberries.The main research results:(1)The results show that 1 kGy 60Co y irradiation,20 ng/L ClO2,2.4 mg/cm3O3,and(50±3)? pre-temperature treatment can enhance the storage quality of blueberries in different degrees,and O3 treatment show the best result in storage.During the 10 days of cold storage,the decay rate of the blueberry fruit of the O3 treatment is 9.49%,below the other three treatments.Ozone treatment shows the good capacity to hold water,compared with the controls,the weight loss less then 55.4%,keeping high TSS,better color,and inhibit the PPO activity.Although 1 kGy 60Co ? could significantly extend the storage period,damage the color of fruit epidermis,affect the fruit browning.Pre-temperature treatment can keep the best color result during storage,but there is no obvious prolongation of storage period.In room temperature,1%chitosan of normal temperature show the best result in storage,could significantly inhibit the PPO activity of blueberry fruit and maintain the higher anthocyanin content,keep lower decay rate,compared with the controls less then 33.9%.But hot water treatment only could reduce to 7.9%,the result is weak then other treatments,and no different with control samples.In cold condition coated with 45 ?chitosan show the best result to enhance the fresh rate.In 10d storage period,45 ?chitosan treatment of the decay rate is 2.76%,better than other treatments.But in the 20 d storage period,the quality of blueberry is decline rapidly,the decay rate is reach to 17,8%.Compared with the ozone treatment,the chitosan coating treatment is weaker than the O3 group,and the weight loss rate of 45 ? chitosan group reached 13.3%during 30d cold storage period,but the O3 treatment was only 4.13%.The same inhibition of TSS content is also weaker than the O3.And the ozone is easy to katabolism,keeping the appearance of the peel,so the choice of ozone as one of the ways of compound treatment.The 60 kPa hypobaric treatment for 1-4 d has significant effect on the storage quality of blueberry.After 10 d storage time in cold condition,the the decay rate of hypobaric treatment for Id still reach to 0%.After 3 days in simulation of shelf life condition,the deccay rate just reached at 5%,significantly higher than other samples,and maintaining the TSS content and the hardness of blueberries,compare with controls is higher then 5.4%and 12.2%,respectively,inhibited the enzyme activity of PG and Cx increased and accumulation of MDA,maintain the anthocyanin content and DPPH radical scavenging ability(50.7%).But long time of hypobaric treatment(3 d,4 d)would stimulate PG activity,is not conducive to maintaining fruit firmness.(2)Comparing with pure hypobaric storage(1d)and ozone treatment,hypobaric treatment combined with ozone treatment were reduced by 21.7%and 49.4%at the end of the 3 d of simulated shelf life.Through inhibiting MDA content,soften fruit and decreased Cx and PG activity.And maintain the anthocyanin content for 2.11 mg/g,DPPH radical scavenging rate is 59.8%,it showed that hypobaric treatment combined ozone treatment can effectively prolong the storage quality "baldwin" blueberry.