| The ripening period of kiwifruit is concentrated,and if kiwifruit is not harvested in time after harvesting maturity,it will affect its storability.At the same time,kiwifruit is sensitive to low temperature,and the lower the maturity,the greater risk of low temperature injury.Pre-storage of hanging trees is a new type of pre-harvest pre-storage method,which properly delays fruits harvest,can reduce the concentration of market pressure to a certain extent,reduce the loss of low temperature damage.'Xixiang' kiwifruit(Actinidia deliciosa)was used as the experimental material in this study,with normal harvest as the control,and pre-storage at different periods as the treatment.Their physiological and quality changes were measured and analyzed during storage.The results showed that:1.Pre-storage of hanging trees had no significant effect on the dry matter content of the fruit,but reduced the firmness,pulp brightness and starch content of the fruit during harvest,shortened the refrigeration period and shelf life time to varying degrees.And the longer the pre-storage time for hanging trees,the more obvious this effect.2.Pre-storage of hanging trees increased the SSC and reduced the titratable acid content during fruit harvest.When the edible firmness was reached,there was no significant difference between the SSC and the titratable acid content of the fruits in different hanging stages.This showd that the SSC content of 'Xuxiang' fruit will not change significantly due to the different hanging time when the fruit is soft ripe.3.Pre-storage of hanging trees caused the emergence of respiratory peak and ethylene peak earlier,reduced the peak of respiratory peak,the peak of amylase activity would be earlier,and the rate of starch degradation would accelerate.4.Although the weight loss rate was longer than the control at the time when hanging trees for a long time,the decay rate was significantly increased,and the eating quality was reduced.The treatment I(hanging trees for 1 week)had the highest VC content and sensory evaluation score and the lowest decay rate,but the shelf life was slightly shorter than the control.5.The activity peaks of CAT,SOD,POD and APX appeared in advance in different pre-storage treatments of hanging trees.Treatment I also significantly increased the activity peaks of these enzymes,and at the same time maintained high activity of CAT and SOD in the later stage,delaying the peroxidation of membrane lipid.6.The chilling injury index,chilling injury rate,relative membrane permeability,MDA and lignin contents of treatment I were the smallest,so treatment I could effectively delay the chilling injury and reduce the chilling injury rate and cold injury index of fruits too long pre-storage time of tree hanging would aggravate the change of relative membrane permeability,promote the accumulation of MDA and lignin,advance the occurrence of chilling injury,and aggravate the symptoms of chilling injury.From the above results,it can be known that pre-storage of hanging trees for 1 week can effectively maintain the fruit's storability and quality,reduce cold sensitivity,and help alleviate the pressure of its harvest period and market concentration.The pre-storage period of the hanging tree is too long,which not only shortens the fruit storage period and shelf life,reduces the edible quality,but also improves its cold sensitivity. |
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