| Yellow-fleshed peach is a characteristic fruit in Hunan Province,with unique taste and rich nutrition,which is widely loved by consumers.However,the yellow-fleshed peach is generally mature and centralized in July to August every year,and can not be stored at room temperature,and the fresh food period is less than 2 months,which seriously impedes the development of the yellow-fleshed peach industry.Therefore,the research on the storage method of the yellow-fleshed peach is of great practical significance.In this study,the effects of pre-harvest bagged treatment,low temperature storage,1-methylcyclopropene(1-MCP)treatment combined with modified atmosphere packaging(MAP)onthe quality of post-harvest storage of "Jinxiu" yellow-fleshed peach varieties from Mayang,Hunan Province were investigated.The main research contents and conclusions of this paper are as follows:(1)To study the effects of preharvest bagging and unbagging treatments on the storage quality of yellow-fleshed peaches.The rot and browning of yellow-fleshed peach fruits in the unbagging group were lighter than the bagging group.Quality analysis showed that the pre-harvest treatment without bagging delayed the reduction of yellow-fleshed peach fruit hardness,total sugar,soluble solids(SSC),titratable acid(TA),total phenols and total flavonoids.Antioxidant analysis showed that the activity of polyphenol oxidase(PPO),peroxidase(POD),superoxide dismutase(SOD)and catalase(CAT)can be maintained without bagging treatment before harvesting,and it is in storage It has a higher antioxidant capacity in the later stage.Correlation analysis showed that the decay rate was significantly positively correlated with antioxidant content and antioxidant enzyme activity(P < 0.05),and highly negatively correlated with nutrient components and total antioxidant activity.Antioxidants(VC,total phenols and total flavonoids)were significantly positively correlated with antioxidant enzyme activities(PPO,POD and SOD)(P < 0.05).The results of hierarchical cluster analysis and principal component analysis(PCA)are roughly the same,which can reflect the similarities and differences between the physiological and biochemical indexes of yellow-fleshed peach fruits.The results showed that the storage quality of yellow-fleshed peach fruits without bagging treatment before harvest was better than that of yellow-fleshed peach fruits bagged before harvest.(2)The low temperature storage of peach fruit storage quality and the effect of antioxidant capacity,the results show that compared with the storage under 4 ℃ and 10 ℃,0 ℃ can significantly inhibit the rotting rate when the peach fruit in postharvest storage,Browning degree and the membrane penetration rate of rise,maintaining high fruit quality and the activity of antioxidant enzymes and total antioxidant capacity.The contents of fruit hardness,total sugar,SSC,TA,VC,total phenols and total flavonoids were maintained at 0 ℃.At the same time,PPO activity,POD activity,SOD activity,CAT activity and total antioxidant capacity were inhibited,which helped to maintain the activity of high antioxidant enzymes,reduce fruit cold injury and other physiological diseases.The 19 physiological and biochemical indexes were divided into two distinct independent clusters by stratified cluster analysis,which was generally consistent with the results of PCA,and could reflect the similarities and differences among physiological and biochemical indexes of yellow-fleshed peach fruit.(3)Effects of 1-MCP treatment and MAP on the quality and volatile organic compounds(VOCs)of yellow-fleshed peach in room temperature storage were studied.Yellow-fleshed peach fruits were treated by four methods,namely nanomaterial packaging(NA),1-MCP fumigation and nanomaterial packaging(1-MCP-NA),polyethylene packaging(PE)and1-MCP fumigation and polyethylene packaging(1-MCP-PE).After 1,4 or10 days of storage,the basic quality changes of the fruits were measured at room temperature.The changes of VOCs in fruits at different storage times were analyzed by headspace gas chromatography-ion mobility spectrometry(HS-GC-IMS)and stoichiometry.A total of 32 VOCs were identified,including terpenes,alcohols,esters,aldehydes and ketones.Through the orthogonal projection of ANOVA and potential structure discriminant analysis,17 VOCs were found to be important compounds,which predicted VIP > 1 and P < 0.05.Compared with the other three treatments,1-MCP-NA could delay and inhibit the reduction of ester and aldehyde content,and the differences between treatment groups were differentiated by PCA and heat map clustering analysis.In conclusion,the results indicated that 1-MCP-NA could maintain the quality and flavor stability of yellow-fleshed peach well. |
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