Effect Of 1-MCP And High Oxygen Treatment On Storage Quality And Physiology Of Apricot (Prunus Armeniaca L.cv.Xiaobai)

Xiaobai apricot（Prunus armeniaca L.cv.Xiaobai）is one of the characteristic fruits in Xinjiang,which has become an oversupplied product in Xinjiang fruit market in recent years because of its rich nutritional value and unique sensory quality.However,the poor post-harvest storage resistance and rapid quality reduction of Xiaobai apricots have greatly affected the market price and profit of Xiaobai apricots.At present,most of the scientific research work at home and abroad is concentrated on the technical research of single storage of Xiaobai apricot after harvesting,and the research results of the method of using combined fresh storage after harvesting are relatively few.Therefore,in this study,1-methylcyclopropene（1-MCP）was used as the raw material to study the changes of storage quality,shelf quality,reactive oxygen species and cell wall metabolism of Xiaobai apricot fruits under the storage conditions of high oxygen treatment,and to provide a theoretical basis for the application of combined storage technology in postharvest storage and preservation of Xiaobai apricot fruits.The main research contents and conclusions of this paper are as follows.（1）The apricots were stored at 60%O₂and 40%N₂,80%O₂and 20%N₂,and 100%O₂to investigate the effects of different high oxygen concentrations on the storage quality of apricots.The effect of 80%O₂and 20%N₂on the storage quality of Xiaobai apricot fruit was significant,and the hardness of apricot fruit was maintained at 15.87 N,and the contents of ascorbic acid（Vitamin C,Vc）were 8.71 mg/100 g,soluble solids content（SSC）and titratable acidity（TA）by the end of storage.The contents of Vc,SSC and TA were 14.21%and 1.06%,which inhibited the respiration intensity of Prunus armeniaca,delayed the ripening process of apricot fruits and maintained the good nutritional quality of apricot fruits.（2）Using Xiaobai apricot as raw material.1-MCP fumigation treatment,80%O₂and 20%N₂treatment and storage with 1-MCP fumigation treatment followed by 80%O₂and 20%N₂treatment were studied to investigate the effects of different treatments on storage quality and shelf life of apricot fruits.The study showed that the preservation effects of 1-MCP,hyperoxia and 1-MCP combined with hyperoxia treatment groups were higher than the control group in all aspects and maintained the nutrient content.Among them,1-MCP combined with hyperoxia treatment had the most significant effect on the storage freshness of apricot fruits,which could better maintain the Vc,SSC and TA contents of apricot fruits at11.13 mg/100 g,15.34%and 1.12%,respectively,by the end of storage,and could effectively slow down the increase of respiration intensity of apricot fruits and delay the appearance of respiration peak of Xiaobai apricot,which prolonged the storage life of fruits to some extent.The storage period of the fruits was extended to some extent.（3）The changes of reactive oxygen species and related metabolic enzymes in apricot fruits were investigated by using Xiaobai apricot as raw material.The study showed that 1-MCP combined with hyperoxia treatment could inhibit the increase of hydrogen peroxide content and superoxide anion production rate during postharvest storage,and effectively increase the activity of catalase（CAT）,peroxidase（POD）and superoxide dismutase（SOD）in Xiaobai apricots,By the end of storage,the CAT activity was 9.45 U/g,POD activity was 1.16 U/g and SOD activity was 1.73 U/g,which reduced the membrane peroxidation of small white apricots;it improved the antioxidant capacity of Xiaobai apricot and delayed the aging of Xiaobai apricot,which was better than the treatment alone for preservation.（4）The changes of metabolic enzymes related to the cell wall of Xiaobai apricot fruit were investigated by different treatments using Xiaobai apricot as raw material.The study showed that 1-MCP combined with hyperoxia treatment could slow down the increase of cell membrane permeability of Xiaobai apricots,which was beneficial to maintain the integrity of the cell membrane and prolong the storage resistance of the fruit;it also inhibited the increase of protopectin content during storage and reduced the expression of polygalacturonase（PG）and cellulase（Cx）in Xiaobai apricots.At the end of storage,the PG activity was 0.78 ug·h^-1·g^-1FW and the Cx activity was 460.43 U/g,which delayed the softening of Xiaobai apricot fruit,prolonged the storage period and improved the economic value of apricot fruit.