Study On The Mechanism Of Acid Electrolyzed Water On The Regulation Of Postharvest Lingwu Long Jujube Senescence

Lingwu long jujube is the most advantageous jujube fruit in Ningxia,rich in a variety of nutrients,known as the "treasure of fruits",deeply loved by consumers.However,as a respiratory leap fruit,Lingwu long jujube has a strong postharvest physiological metabolism and is extremely prone to quality deterioration.Without any treatment conditions,the storage life of jujube fruit does not exceed 10 days,which seriously affects the edible quality,industrial development and long-term storage of jujube fruit,resulting in greater economic losses.Therefore,it is urgent to use new,safe,environmentally friendly and low-cost preservation technology to preserve Lingwu long jujube,so as to extend the shelf life and maintain better storage quality.In this study,the effects of acidic electrolyzed water(AEW)on quality,reactive oxygen species metabolism,phenylpropane metabolism,cell wall metabolism and energy respiration metabolism of Lingwu long jujube during storage were studied,and the differentially expressed genes were analyzed from the transcriptomics,and the results will provide a theoretical basis for AEW treatment to delay the senescence of jujube.The main findings are as follows:(1)Effects of AEW treatment on jujube quality and redox equilibrium.The results showed that AEW treatment could significantly reduce the respiration rate and browning index of jujube,inhibit the decrease of L*and b*values of jujube,reduce the a*value,and maintain high soluble solids content.AEW treatment could inhibit the production of excess reactive oxygen species and enhance the antioxidant system,which may be due to AEW induced improvement of DPPH scavenging capacity,enhanced catalase and superoxide dismutase activities,and promoted the improvement of ascorbic acid and glutathione and ascorbyl peroxidase,glutathione reductase,monodehydroascorbate reductase and dehydroascorbate reductase and other glutathione cycle-related substances and enzyme activities.(2)Effect of AEW treatment on jujube phenylpropane and cell wall metabolism.The results showed that AEW treatment could significantly reduce the increase of postharvest disease index and fruit firmness of jujube fruit,and the enhancement of disease resistance of jujube fruit was due to phenylalanine amino lyase,cinnamate-4-hydroxylase and 4-coumarate-CoA ligase activities activation and total phenol and total flavonoids contents increase.In addition,AEW treatment could reduce polygalacturonase,pectinate lyases,β-galactosidase,and cellulase activities and inhibit the degradation of water-soluble pectin,Na2CO3-soluble pectin,cellulose,and hemicellulose for delaying fruit softening,thereby alleviating the occurrence of jujube fruit diseases and maintaining fruit quality.(3)Effects of AEW treatment on jujube energy and respiratory metabolism.The results showed that AEW treatment was superior to the control group in maintaining the overall quality and senescence of jujube fruit,most likely due to the higher energy status.AEW treatment maintained ATP content and energy charge by activating succinate dehydrogenase,cytochrome C oxidase,H+-ATPase,and Ca2+ATPase activities.In addition,AEW treatment activated nicotinamide adenine dinucleotide kinase,glucose-6-phosphate dehydrogenase,and 6-phosphogluconate dehydrogenase activities in jujube fruit,resulting in the NADP+and NADPH contents increased,inhibiting ROS bursts,thereby alleviating membrane lipid peroxidation.These results suggested that AEW treatment is an effective strategy to delay the senescence of jujube fruit by regulating energy status and pyridine nucleotide homeostasis.(4)AEW treatment for postharvest transcriptome analysis of jujube fruit.The results showed that the GO items mainly enriched during the senescence process of jujube fruit were catalytic activity,integration,cell fraction,membrane part,cellular process,and metabolic process.The DEGs between CK10_vs_CK0,CK20_vs_CK0,AEW10_vs_CKO and AEW20_vs_CKO were mainly enriched in KEGG pathways such as carotenoid biosynthesis,galactose metabolism,glycerophospholipid metabolism,ribosomes,photosynthesis,arginine biosynthesis,etc.Whereas the DEGs between AEW10_vs_CK10 and AEW20_vs_CK20 were mainly enriched in the KEGG pathways such as amino sugar and nucleotide sugar metabolism,ribosomes,photosynthesis,α-linolenic acid metabolism,C5 branched-chain diacid metabolism and valine,leucine and isoleucine biosynthesis.In addition,the expression of DEGs associated with jujube fruit senescence,such as ROS metabolism,phenylpropane biosynthesis,cell wall metabolism,plant hormone signaling,glycolysis pathway,citric acid cycle,pentose phosphate pathway,and oxidative phosphorylation-related genes,were screened and regulated by AEW treatment.