The Research Of UV-C Treatment On Chilling Injury And Endogenous Polyamines Of Tribute Orange

Citrus has a high economic and nutritional value as a kind of fruit planted in tropical and subtropical areas.It is loved by the majority of consumers.However,citrus is prone to injury and microbial injection during post-harvest storage and transportation,thus affecting its quality.Low temperature storage is one of the popular post-harvest storage means of citrus.However,the storage at inappropriate low temperature can cause chilling injury of citrus and thus cause serious economic losses.This experiment chose royal tribute orange as material,and by storage at different low temperatures,determines the optimal storage temperature for royal tribute orange.By treatments of different doses of UV-C before storage,this experiment studies the effects of UV-C treatment on royal tribute orange and related secondary metabolism,thus providing the basis for the application of UV-C treatment in royal tribute orange storage.The results showed that:1.Among the three temperature treatment groups(1℃,4℃、7℃),when storage at 4℃ and 7℃, the royal tribute orange could keep good taste,reduce the weight loss and respiratory rate,inhibit the accumulation of MDA,increase defense enzyme activity and delay senescence of royal tribute orange fruits.After being storaged at 1℃ for some time.the royal tribute orange fruits had some changes,such as breathing anomalies,MDA accumulation and increase of cell membrane permeability,which resulted in royal tribute orange chilling injury.POD,SOD,CAT enzyme activity continued to decrease and ethanol,acetaldehyde accumulated,thus affecting the flavor and quality of fruits.2.Appropriate doses of UV-C treatments(1KJ/m2、3KJ/m2)could postpone and slow chilling injury in royal tribute orange fruits,reduce weight loss,improve fruit TSS content,reduce membrane permeability,inhibit the accumulation of MDA.improve fruit POD,SOD,CAT activity and reduce membrane lipid peroxidation.The effects of 3KJ/m2 treatment was better than that of 1KJ/m2 treatment.5KJ/m2 UV-C treatment caused excessive stress on fruits and damage on cell membrane,increased membrane permeability significantly,intensified fruit senescence and cold damage and shortened the storage period of royal tribute orange.UV-C treatment could also inhibit the growth of mold on the surface of royal tribute orange and prolong storage life of it.Among the three treatment groups,the effect of inhibition of 3KJ/m2 treatment was the best.3KJ/m2 treatment could significantly improve the content of putrescine and spermidine in royal tribute orange fruits and improve stress response of royal tribute fruits to low temperature stress.