ABSTRACT
BACKGROUND: Ziziphus jujuba Miller cv. Dongzao is extremely susceptible to reddening, browning, nutritional loss, and perishability after harvest. In this study, we evaluated the mechanisms of calcium chloride and chitosan/nano-silica composite film treatments on the quality, especially in reddening, by physiological and metabolomic assays. RESULTS: The treatment delayed the decline of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), and chalcone isomerase (CHI) activities. Meanwhile, the treated groups retarded the increases in anthocyanin and quercetin contents by inhibiting the gene expressions of flavonol synthase (ZjFLS), dihydroflavonol 4-reductase (ZjDFR), and anthocyanidin synthase (ZjANS), while promoting leucoanthocyanidin reductase (ZjLAR) expression, which leads to retardation of fruit reddening. Anthocyanins were found to be responsible for post-harvest winter jujube reddening through principal component analysis. Results from the technique for order preference by similarity to an ideal solution indicated that the treated group delayed the decline of the quality of 'Dongzao' and extended its shelf life. CONCLUSION: The treatment induced the heightening of flavonoids metabolism. They enhanced the nutritional value and the ability to resist stress by delaying the decline of PAL, CHS, and CHI activities. Meanwhile, the treated groups retarded the increase in anthocyanin and quercetin contents by inhibiting the gene expressions of ZjFLS, ZjDFR, and ZjANS and promoting ZjLAR expression, which leads to retardation of fruit reddening. Anthocyanins are responsible for post-harvest winter jujube reddening. Coating treatment effectively delayed the decline of winter jujube quality. © 2020 Society of Chemical Industry.
Subject(s)
Calcium Chloride/pharmacology , Food Preservation/methods , Fruit/chemistry , Ziziphus/drug effects , Anthocyanins/analysis , Anthocyanins/metabolism , Food Preservation/instrumentation , Fruit/drug effects , Fruit/enzymology , Fruit/genetics , Gene Expression Regulation, Plant , Oxidoreductases/genetics , Oxidoreductases/metabolism , Oxygenases/genetics , Oxygenases/metabolism , Phenylalanine Ammonia-Lyase/genetics , Phenylalanine Ammonia-Lyase/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Quercetin/analysis , Quercetin/metabolism , Ziziphus/chemistry , Ziziphus/enzymology , Ziziphus/geneticsABSTRACT
BACKGROUND: Trisodium phosphate (TSP), generally recognized as safe (GRAS), could control postharvest diseases and maintain fruit quality. However, changes of fruit quality and sucrose metabolism in harvested jujube after TSP treatment remain largely unknown. In the current study, jujube fruit (cv. sanxing) was used to study the effects of TSP on storage quality and sucrose metabolism during storage at 20 ± 2 °C with 40-50% relative humidity (RH). RESULTS: The results showed that 0.5 g L-1 TSP treatment reduced weight loss and reduced sugar content, suppressed the reduction of fruit firmness, maintained ascorbic acid (AsA) content and inhibited respiratory rate of jujube fruit. In addition, TSP treatment also reduced acid invertase (AI) and neutral invertase (NI) activities in sucrose metabolism in jujube fruit. Sucrose synthase-cleavage (SS-c), sucrose synthase-synthesis (SS-s) and sucrose phosphate synthase (SPS) activities were also suppressed by TSP treatment. CONCLUSION: Treatment with TSP could effectively reduce enzymes activities in sucrose metabolism and maintain storage quality of jujube fruit during storage. © 2019 Society of Chemical Industry.
Subject(s)
Food Preservatives/pharmacology , Fruit/chemistry , Phosphates/pharmacology , Ziziphus/drug effects , Food Preservation , Food Storage , Fruit/drug effects , Glucosyltransferases/metabolism , Plant Proteins/metabolism , Quality Control , Sucrose/analysis , Ziziphus/chemistryABSTRACT
In this study, we found that oxalic acid (OA) at the concentration of 5 mM could delay jujube fruit sene-scence by reducing ethylene production, repressing fruit reddening and reducing alcohol content, which consequently increased fruit resistance against blue mold caused by Penicillium expansum. In order to gain a further understanding of the mechanism by which OA delays senescence and increases disease resistance of jujube fruit, we used a proteomics approach to compare soluble proteome of jujube fruits treated with water or 5 mM OA for 10 min. A total of 25 differentially expressed proteins were identified by using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF-MS/MS). Among these proteins, alcohol dehydrogenase 1, which plays a direct role in ethanol metabolism, was repressed, and the abundances of three photosynthesis-related proteins was enhanced in jujube fruit after OA treatment. The protein identified as a cystathionine beta-synthase domain-containing protein, which can regulate ethylene precursors, was also induced by OA treatment. The activity of 1-aminocyclopropane-1-carboxylic acid synthase was significantly suppressed in OA-treated jujube fruit. In addition, three proteins related to the defense/stress response were up-regulated by OA, and contributed to the establishment of systemic resistance induced by OA in jujube fruits. These results indicated that OA treatment might affect ethanol and ethylene metabolism, resulting in delaying senescence, and increase resistance of jujube fruits against fungal pathogens.