Effects Of Heat Shock,Ozone Treatment And Green Mould Infection On The Microstructure And Composition Of The Cuticle Of Satsuma Mandarin

In this study,Satsuma mandarin was used as the experimental material to study the effects of heat shock,ozone treatment and green mold infection on fruit quality and surface cuticle.Firstly,the effects of heat shock and ozone treatment on the main physiological indicators of Satsuma mandarin fruit were studied during the storage at room temperature(25 ℃),Secondly,The morphological changes of the waxy crystals of the fruit epidermis were observed with these two treatments.Finally,the effect of citrus green mold(Penicillium digitatum)on the chemical composition and content of the cuticle of tangerine tangerine was discussed.the results showed as follows:In the storage process at room temperature,through orthogonal experiment design,the optimal conditions of heat shock treatment were obtained based on the indicators of good fruit rate and weight loss rate.The results showed that the best heat shock condition for Satsuma mandarin was 52 ℃ and the treatment time was3 min.Appropriate heat shock treatment before storage can inhibit the rot and weightlessness of Satsuma mandarin fruit,slow down the hardness,soluble solids(Soluble Solids Content,SSC),titratable acid(TA),and vitamin C content;Compared with the control group,the main chemical components of the fruit wax and cutin in the treatment group were basically the same,but the wax and cutin contents in each storage period were higher than those in the control group,and the content of the cuticles in different components was significantly different.Terpenoids were not detected in the treatment group after storage for 28 days.Scanning electron microscopy observations showed that the wax crystals in the control group were small and irregular platelets,and had a tendency to increase first and then decrease during storage.After heat treatment,the wax crystals of the fruit melted and redistributed under heat Fill wax gaps and cover pores.This indicates that heat shock treatment will affect the change of fruit epidermal wax,thus affecting the rate of post-harvest storage water loss.After the ozone treatment of Satsuma mandarin for 28 days at room temperature,the weight loss rate of the fruits in the ozone treatment group was controlled below 10%,which better maintained the fruit’s hardness,SSC,TA,and vitamin C content,and maintained the freshness and consumption of fruits quality.After ozone treatment,the wax and cutin contents on the surface of Satsuma mandarin fruit were the same as those in the control group,both increased first and then decreased.The content difference is obvious,such as β-tocopherol is only detected in the control group.During storage,the morphological changes of the wax crystals in the epidermis of Satsuma mandarin treated with ozone are significantly different from those in the control group.The main reason is that the stomata were closed before the Satsuma mandarin was stimulated by ozone.With the prolonged storage time,the surface of its waxy layer becomes smoother,forming a thicker waxy film.A small amount of waxy crystals pile up into flakes,and then slowly fall off,leaving a smooth wax film to facilitate fruit storage.This paper also studied the effects of green mold infection on the composition and microstructure of the cuticle of citrus epidermis after different postharvest treatments.The results showed that green mold infects the cuticle of Satsuma mandarin cuticle after heat treatment,ozone treatment and cold water treatment,respectively.Changes,the fruit epidermal waxy and cutin content of each group were significantly different,but the main components of the waxy and cutin of each group were the same.Scanning electron microscopy results showed that the morphological content of wax crystals in each group was significantly different.The wax film of the fruit skin in the heat treatment group was shrunken and accompanied by a small amount of small,irregular platelet-like wax crystals;the wax film of the fruit skin in the ozone treatment group was smooth and have no Small,irregular waxy crystals;the cold-treated group’s fruit epidermal wax film is smooth,with a small amount of shrinkage,and there are a few small,irregular platelet-like waxy and massive waxy crystals on the wax film;the control group’s fruit waxy crystals Mostly irregular,flat platelet-shaped and more dispersed.