Lysozyme amyloid fibril-chitosan double network hydrogel: Preparation, characterization, and application on inhibition of Nε-(carboxyethyl)lysine.

Nε-(carboxyethyl)lysine (CML), a typical advanced glycosylation end product produced during the processing of meat under high temperature, poses health risks. Active substances like polyphenols are known to inhibit the formation of harmful products during the processing of food. In this study, our objective was to prepare a double network hydrogel (DN) loaded with gallic acid using amyloid fibers and chitosan as a rigid and flexible network, respectively. The network as well as the interactions between the two networks were observed and analyzed. Chitosan concentration was the key factor regulating the structure and properties of the DN. At a chitosan concentration of 0.7%wt, the structure of DN became dense and its mechanical properties were improved, with the loading capacity and loading efficiency being increased by 143.79 % and 128.21 %, compared with those of amyloid fibril alone. Furthermore, the digestibility of gallic acid in simulated intestinal fluid was increased by 215.10 %. Moreover, adding DN to the beef patties effectively inhibited the formation of CML in a dose-response dependent manner. Addition of 3 wt% DN resulted in the inhibitory rate of CML in roast beef patties reaching a high 73.09 %. The quality and palatability of beef patties were improved. These findings suggest that DN shows great potential as an application that may be utilized to deliver active substances aimed at inhibiting CML in the meat processing industry.

An update of aurones: food resource, health benefit, biosynthesis and application.

Aurones are a subclass of active flavonoids characterized with a scaffold of 2-benzylidene-3(2H)-benzofuranone. This type of chemicals are widely distributed in fruit, vegetable and flower, and contribute to human health. In this review, we summarize the natural aurones isolated from dietary plants. Their positive effects on immunomodulation, antioxidation, cancer prevention as well as maintaining the health status of cardiovascular, nervous system and liver organs are highlighted. The biosynthesis strategies of plant-derived aurones are elaborated to provide solutions for their limited natural abundance. The potential application of natural aurones in food coloration are also discussed. This paper combines the up-to-date information and gives a full image of dietary aurones.

Stability and bioactivity evaluation of black pepper essential oil nanoemulsion.

Black pepper essential oil has the same disadvantages as other plant essential oils, such as volatilization, high sensitivity to light and heat and poor water solubility, which leads to great limitations in application. This study improved the stability and antibacterial properties of black pepper essential oil (BPEO) based on a nano-emulsification process. Tween 80 was selected as the emulsifier to prepare the BPEO nanoemulsion. Gas chromatograph - mass spectrometer (GC-MS) was used to analyze the composition of BPEO, of which d-limonene was the main component (37.41%). After emulsification, black pepper nanoemulsion was obtained (droplet size was 11.8 nm). The water solubility and stability of the emulsions at 25 °C were also improved with decreasing particle size. Antimicrobial properties of plant pathogens (Colletotrichum gloeosporioides, Botryodiplodia theobromae) and foodborne pathogens (Staphylococcus aureus, Escherichia coli) were evaluated by disk diffusion and other techniques for determining minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). With 12.5 mg mL-1 MIC and 25 mg mL-1 MBC, BPEO inhibited the growth of two tested plant pathogens and two foodborne pathogens. Essential oils (EO) were encapsulated in a nanoemulsion system to enhance the bacteriostatic effect of essential oils and reduce MIC and MBC concentrations. After emulsification, the biological activity (antimicrobial and antioxidant) of the BPEO nanoemulsion was considerably improved, nano-emulsification had certain significance for the study of EOs.

Advances in gas fumigation technologies for postharvest fruit preservation.

This work summarizes the application of gas fumigation technology in postharvest fruit quality management and related biochemical mechanisms in recent years. Gas fumigants mainly include SO2, ClO2, ozone, NO, CO, 1-MCP, essential oils, H2S and ethanol. This work indicated that gas fumigation preservatives can effectively improve postharvest fruit quality, which is mainly manifested in delaying senescence, inhibiting browning, controlling disease and alleviating chilling injury. Gas preservatives are mainly involved in postharvest fruit quality control in the roles of antifungal agent, anti-browning agent, redox agent, ethylene inhibitors, elicitor and pesticide remover. Different gas preservatives have different roles, but most of them have multiple roles at the same time in postharvest fruit quality management. In addition, the role of some gas preservatives with direct antifungal activity in the control of postharvest fruit diseases can also activate defense systems to improve fruit resistance. It should be noted that some gas fumigation treatments with slow-release effects have been developed recently, which may allow gas fumigation gases to perform better. Moreover, some gas fumigants can cause irrational side effects on the fruit and some combined treatments need to be found to counteract such side effects.

Attenuation of Postharvest Browning in Rambutan Fruit by Melatonin Is Associated With Inhibition of Phenolics Oxidation and Reinforcement of Antioxidative Process.

Rambutan is a famous tropical fruit with a unique flavor and considerable economic value. However, the high vulnerability to postharvest browning leads to a short shelf life of rambutan fruit. Melatonin (MT) is an excellent bioactive molecule that possesses the potential to improve the storability of the harvested crops. In this study, the physiological mechanism of exogenous MT in affecting pericarp browning and senescence of postharvest rambutan fruit was investigated. Experimental results showed that the application of MT at 0.125 mmol L-1 appreciably retarded the advancement of pericarp browning and color parameters (L*, a*, and b*). MT treatment inhibited the increase in membrane relative electrolytes leakage (REL) while lowering the accumulation of reactive oxygen species (ROS) (■O2 - and H2O2) and malonaldehyde (MDA). Reduced phenolics oxidation, as indicated by higher contents of total phenolics, flavonoids, and anthocyanins along with fewer activities of peroxidase (POD) and polyphenol oxidase (PPO), was detected in MT fruit compared with control fruit. MT treatment maintained the cellular redox state by inducing antioxidant enzyme activity and reinforcing the ascorbate-glutathione (AsA-GSH) cycle. Furthermore, the ultrastructural observation revealed that the spoilage of cellular and subcellular structures was milder in MT fruit than that in control fruit. The results suggest that MT could ameliorate the browning and senescence of rambutan fruit by inhibiting phenolic oxidation and enhancing the antioxidative process.

Abnormal chilling injury of postharvest papaya is associated with the antioxidant response.

Generally, the lower the temperature and/or the longer the duration of low temperature, the more serious chilling injury (CI) symptom appears in fruit. However, our previous study showed that the higher storage temperature (6°C) resulted in a more serious CI in papaya fruit compared to that stored at 1°C, which could be viewed as an abnormal CI behavior. This study investigated the antioxidant responses that existed in abnormal CI behavior of papaya fruit. Compared to 6°C, antioxidant enzyme activities of papaya fruit which was stored at 1°C were maintained at a higher level while the circulatory metabolism of the ascorbate-glutathione cycle (AsA-GSH) was more vigorous in papaya fruit, as indicated by higher superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR) activities and higher AsA and GSH levels, which could reduce the superoxide anion (·O2 - ) production rate and the hydrogen peroxide (H2 O2 ) content. Suppressed reactive oxygen species (ROS) generation in papaya fruit at 1°C resulted in reduced membrane permeability and malondialdehyde (MDA) accumulation when compared to that at 6°C, thus the development of CI was restricted during storage at 1°C. This study deepened the understanding of differential antioxidant responses during cold storage at 1°C and 6°C in papaya fruit and provided a theoretical basis for further study on the mechanism of the abnormal CI behavior in papaya fruit. PRACTICAL APPLICATIONS: Low-temperature storage is one of the most effective methods to preserve fruit and vegetable products. While, inappropriate low temperature could induce CI, and the damage caused by CI is often more serious than estimated. Therefore, it is necessary to study the physiological and biochemical characteristics of different postharvest fruits and vegetables to prolong storage period, improve storage quality and reduce the loss of products. This study analyzed the antioxidant reaction in abnormal CI behavior of papaya, which could contribute to the further study on the mechanism of CI in papaya fruit and provide theoretical basis for the development of preservation technology of papaya fruit.

Antibacterial mechanism of linalool emulsion against Pseudomonas aeruginosa and its application to cold fresh beef.

Pseudomonas aeruginosa (P. aeruginosa) is the dominant spoilage bacterium in cold fresh beef. The current strategy is undertaken to overcome the low water solubility of linalool by encapsulating linalool into emulsions. The results of field emission scanning electron microscopy and particle size distribution revealed that the appearance of the bacterial cells was severely disrupted after exposure to linalool emulsion (LE) with an minimum inhibitory concentration (MIC) of 1.5 mL/L. Probes combined with fluorescence spectroscopy were performed to detect cell membrane permeability, while intracellular components (protein and ion leakage) and crystal violet staining were further measured to characterize cell membrane integrity and biofilm formation ability. The results confirmed that LE could destroy the structure of the cell membrane, thereby leading to the leakage of intracellular material and effective removal of biofilms. Molecular docking confirmed that LE can interact with the flagellar cap protein (FliD) and DNA of P. aeruginosa, inhibiting biofilm formation and causing genetic damage. Furthermore, the results of respiratory metabolism and reactive oxygen species (ROS) accumulation revealed that LE could significantly inhibit the metabolic activity of P. aeruginosa and induce oxidative stress. In particular, the inhibition rate of LE on P. aeruginosa was 23.03% and inhibited mainly the tricarboxylic acid cycle (TCA). Finally, LE was applied to preserve cold fresh beef, and the results showed that LE could effectively inhibit the activity of P. aeruginosa and delay the quality change of cold fresh beef during the storage period. These results are of great significance to developing natural preservatives and extending the shelf life of cold fresh beef.

Enzymatic browning in relation to permeation of oxygen into the kernel of postharvest areca nut under different storage temperatures.

Previous study indicates that kernel of areca nut is susceptible to enzymatic browning caused by phenolic oxidation, which involves the ingression of oxygen into interior tissue. However, the reason for permeation of oxygen into the interior of areca nut and its possible influencing factors (e.g., temperatures) are little known. In the present study, we set three storage temperatures (25, 10, and 5°C) and investigated the effects on kernel browning and related physic-biochemical and tissue morphological changes. The results showed that the most severe kernel browning was observed in areca nut stored at 25°C, followed by 5°C. Comparatively, a slower browning development was found in areca nut stored at 10°C. More serious kernel browning at 25 and 5°C might be attributed to increased membrane permeability and aggravated tissue damage in view of morphological observations on pericarp, mesocarp, and kernel shell. Higher lignin content and phenylalanine ammonia-lyase activity were observed in mesocarp of areca nuts stored at 25 and 5°C as compared to 10°C, indicating that mesocarp lignification could facilitate the permeability of oxygen. Furthermore, the data showed that storage at 25 and 5°C induced the higher polyphenol oxidase activity while accelerating the decline in total phenolic content in areca nut kernel, which could contribute to higher occurrence of enzymatic browning reaction compared to that at 10°C. These results suggest that natural senescence at 25°C and severe chilling stress at 5°C could be influencing factors triggering the permeation of oxygen, leading to internal kernel browning in areca nut.

Effects of hydrogen water treatment on antioxidant system of litchi fruit during the pericarp browning.

Litchi fruit were exposed to 0.7 PPM hydrogen water (HW) before storage at 25 ± 1 â„ƒ. HW treatment delayed the pericarp browning and maintained the total soluble solids (TSS) of litchi fruit. Then, a total of 25 antioxidant system-related characters were determined to evaluate the effects of HW on antioxidant system during pericarp browning. Compared with control pericarp, the pericarp of HW-treated litchi fruit exhibited higher levels of superoxide radical (O2-·) scavenging activity, glutathione (GSH), monodehydroascorbate reductase (MDHAR), polyphenol oxidase (PPO) and total flavonoids during whole storage, higher levels of hydrogen peroxide (H2O2), catalase (CAT), glutathione disulfide (GSSG), ascorbate oxidase (AAO) and total phenols only on day 1, and higher levels of ascorbate peroxidase (APX), total anthocyanin, glutathione reductase (GR) and glutathione peroxidases (GPX) at later stage of storage. Those HW-induced antioxidant system-related characters might directly or indirectly enhanced the antioxidant capacity and delayed the pericarp browning of litchi.

Study on the browning mechanism of betel nut (Betel catechu L.) kernel.

Taking betel nut (Betel catechu L.) kernel as raw materials, to analyze the browning mechanism of betel nut kernel. First, we extract and separate the phenolic substances and polyphenol oxidase (PPO) from the betel nut kernel and then find out how O2 penetrates into the kernel, study the above 3 key factors of enzymatic browning so as to prove the possibility of enzymatic browning, and further study the browning products to clarify the mechanism of browning of betel nut kernel during storage process. The results showed that 11 kinds of phenolic compounds were isolated and identified from the betel nut kernel by liquid chromatography-mass spectrometry, among which chlorogenic acid was the highest, followed by dopamine and L-epicatechin, and other contents were relatively low. Meanwhile, PPO was also separated from the betel nut kernel by DEAE-Sepharose Fast Flow and Phenyl-Sepharose 6 Fast Flow column chromatography. On this basis, scanning electron microscopy showed that the damage of the betel nut tissue was aggravated with the prolonged storage time, the wax was gradually decomposed, and the stratum corneum of the peel is destroyed in a honeycomb-shaped; the lignification of the flesh was aggravated, and the interstitial space was increased; and the crack of the kernel membrane was also enlarged. These changes of structure contribute to increase gas exchange within and outside the organization, including the entry of O2. Finally, the oxidation products generated from simulated reaction of chlorogenic acid, dopamine, and epicatechin with purified PPO under aerobic conditions in vitro were compared with the products extracted from naturally brown betel nut, and the same absorption spectra were found. Therefore, it indicates that the browning of betel nut kernel is an enzymatic browning caused by the reaction of phenolic substrates were oxidized by PPO.

Melatonin Enhances Cold Tolerance by Regulating Energy and Proline Metabolism in Litchi Fruit.

Melatonin (MLT) is a vital signaling molecule that regulates multiple physiological processes in higher plants. In the current study, the role of MLT in regulating chilling tolerance and its possible mechanisms in litchi fruit during storage at ambient temperatures after its removal from refrigeration was investigated. The results show that the application of MLT (400 µM, dipping for 20 min) to 'Baitangying' litchi fruit effectively delayed the development of chilling injury (CI) while inhibiting pericarp discoloration, as indicated by higher chromacity values (L*, a*, b*) and anthocyanin levels. MLT treatment suppressed the enhancements of the relative electrical conductivity (REC) and malondialdehyde (MDA) content, which might contribute to the maintenance of membrane integrity in litchi fruit. MLT treatment slowed the decline in cellular energy level, as evidenced by higher adenosine triphosphate (ATP) content and a higher energy charge (EC), which might be ascribed to the increased activities of enzymes associated with energy metabolism including H+-ATPase, Ca2+-ATPase, succinate dehydrogenase (SDH), and cytochrome C oxidase (CCO). In addition, MLT treatment resulted in enhanced proline accumulation, which was likely a consequence of the increased activities of ornithine-δ-aminotransferase (OAT) and Δ1-pyrroline-5-carboxylate synthase (P5CS) and the suppressed activity of proline dehydrogenase (PDH). These results suggest that the enhanced chilling tolerance of litchi fruit after MLT treatment might involve the regulation of energy and proline metabolism.

Effect of glycine betaine on chilling injury in relation to energy metabolism in papaya fruit during cold storage.

"Zhongbai" papaya fruit were treated with 15 mmol/L glycine betaine (GB) and then refrigerated at 6°C for 40 days to study the influence of GB on chilling injury (CI) and possible mechanism associated with energy metabolism. The results exhibited that GB treatment remarkably reduced the CI severity as indicated by lower CI index during storage. GB treatment lowered electrolyte leakage and malondialdehyde content, which accounted for maintenance of membrane integrity and reduced lipid peroxidation. Moreover, GB treatment improved the energy status as revealed by increased adenosine triphosphate (ATP) level, energy charge, and activities of energy metabolism-related enzymes including mitochondrial membrane H+-adenosine triphosphatase (H+-ATPase) and Ca2+-adenosine triphosphatase (Ca2+-ATPase), succinate dehydrogenase (SDH), and cytochrome C oxidase (CCO). The results indicate that enhanced chilling tolerance in papaya fruit by GB treatment during cold storage might be ascribed to improved energy status in association with increased activities of energy metabolism-related enzymes.

Comparative volatile compounds and primary metabolites profiling of pitaya fruit peel after ozone treatment.

BACKGROUND: Ozone treatment can effectively inhibit fruit decay in many fruits during postharvest storage. However, little information is available for pitaya fruit. RESULTS: Ozone treatment significantly reduced the decay rate and induced the enzyme activities of peroxidase and polyphenol oxidase, and also reduced the levels of reactive oxygen species. In total, 103 metabolites were detected and changed the content after ozone treatment, including 54 primary metabolites and 49 aromatic compounds. After significance and importance analysis, 37 metabolites were important. Some metabolites were induced by peel senescence to respond to senescence stress, including d-fructose, d-glucose, mannose, inositol, galactonic acid, ethanedioic acid and stearic acid. Some metabolic products of peel senescence were reduced by ozone treatment, including d-arabinose, glucaric acid, galacturonic acid, 1-hexanol, 4-ethylcyclohexanol, ß-linalool, palmitoleic acid and 2-hydroxy-cyclopentadecanone. Some metabolites induced by ozone treatment might play a vital role in delaying the senescence and decay, including malic acid, succinic acid, pentenoic acid, eicosanoic acid, 2-hexenal, hexanal, 2-heptenal, 4-heptenal, 2-octenal and nitro m-xylene. CONCLUSION: Ozone treatment significantly reduced decay and prolonged shelf-life without reducing fruit quality. In total, 37 metabolites might play an important role in ozone delayed fruit decay. © 2018 Society of Chemical Industry.

Delay of Postharvest Browning in Litchi Fruit by Melatonin via the Enhancing of Antioxidative Processes and Oxidation Repair.

Melatonin acts as a crucial signaling and antioxidant molecule with multiple physiological functions in organisms. To explore effects of exogenous melatonin on postharvest browning and its possible mechanisms in litchi fruit, 'Ziniangxi' litchi fruits were treated with an aqueous solution of melatonin at 0.4 mM and then stored at 25 °C for 8 days. The results revealed that melatonin strongly suppressed pericarp browning and delayed discoloration during storage. Melatonin treatment reduced relative membrane-leakage rate and inhibited the generation of superoxide radicals (O2-·), hydrogen peroxide (H2O2), and malondialdehyde (MDA). Melatonin treatment markedly promoted the accumulation of endogenous melatonin; delayed loss of total phenolics, flavonoids, and anthocyanins; and enhanced the activities of antioxidant enzymes, including superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2). By contrast, the activities of browning-related enzymes including polyphenoloxidase (PPO, EC 1.10.3.1) and peroxidase (POD, EC 1.11.1.7) were reduced. In addition, melatonin treatment up-regulated the expression of four genes encoding enzymes for repair of oxidized proteins, including LcMsrA1, LcMsrA2, LcMsrB1, and LcMsB2. These findings indicate that the delay of pericarp browning and senescence by melatonin in harvested litchi fruit could be attributed to the maintenance of redox homeostasis by the improvement of the antioxidant capacity and modulation of the repair of oxidatively damaged proteins.

Effect of postharvest spray of apple polyphenols on the quality of fresh-cut red pitaya fruit during shelf life.

Fresh-cut (FC) red pitaya fruit were treated with 5ga.i.l-1 apple polyphenols (APP) and then stored at 20°C for up to 4days to evaluate the effects on attributes. Results showed that FC pitaya fruit with APP treatment showed greater colour retention, delayed softening, reduced loss of soluble solids content, titratable acidity, betacyanin and total phenolics compared with untreated FC fruit. APP treatment also maintained antioxidant activity, as indicated by higher DPPH radical-scavenging activity and reducing power compared with untreated FC pitaya fruit. APP treatment strongly suppressed microbial growth, contributing to improvement of product safety. Because APP is a natural product, we propose that application of APP could be a convenient, safe and low-cost approach to maintain the quality and extend the shelf life of FC red pitaya fruit.

Comparative transcriptome and metabolome provides new insights into the regulatory mechanisms of accelerated senescence in litchi fruit after cold storage.

Litchi is a non-climacteric subtropical fruit of high commercial value. The shelf life of litchi fruit under ambient conditions (AC) is approximately 4-6 days. Post-harvest cold storage prolongs the life of litchi fruit for up to 30 days with few changes in pericarp browning and total soluble solids. However, the shelf life of litchi fruits at ambient temperatures after pre-cold storage (PCS) is only 1-2 days. To better understand the mechanisms involved in the rapid fruit senescence induced by pre-cold storage, a transcriptome of litchi pericarp was constructed to assemble the reference genes, followed by comparative transcriptomic and metabolomic analyses. Results suggested that the senescence of harvested litchi fruit was likely to be an oxidative process initiated by ABA, including oxidation of lipids, polyphenols and anthocyanins. After cold storage, PCS fruit exhibited energy deficiency, and respiratory burst was elicited through aerobic and anaerobic respiration, which was regulated specifically by an up-regulated calcium signal, G-protein-coupled receptor signalling pathway and small GTPase-mediated signal transduction. The respiratory burst was largely associated with increased production of reactive oxygen species, up-regulated peroxidase activity and initiation of the lipoxygenase pathway, which were closely related to the accelerated senescence of PCS fruit.

Enzymatic browning and antioxidant activities in harvested litchi fruit as influenced by apple polyphenols.

'Guiwei' litchi fruit were treated with 5 ga.i. L(-1) apple polyphenols (APP) and then stored at 25°C to investigate the effects on pericarp browning. APP treatment effectively reduced pericarp browning and retarded the loss of red colour. APP-treated fruit exhibited higher levels of anthocyanins and cyanidin-3-rutinoside, which correlated with suppressed anthocyanase activity. APP treatment also maintained membrane integrity and reduced oxidative damage, as indicated by a lower relative leakage rate, malondialdehyde content, and reactive oxygen species (ROS) generation. The data suggest that decompartmentalisation of peroxidase and polyphenoloxidase and respective browning substrates was reduced. In addition, APP treatment enhanced the activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase), as well as non-enzymatic antioxidant capacity (DPPH radical-scavenging activity and reducing power), which might be beneficial in scavenging ROS. We propose that APP treatment is a promising safe strategy for controlling postharvest browning of litchi fruit.

Low-temperature conditioning induces chilling tolerance in 'Hayward' kiwifruit by enhancing antioxidant enzyme activity and regulating en-dogenous hormones levels.

BACKGROUND: To understand the mechanisms leading to the enhanced chilling tolerance of kiwifruit by low-temperature conditioning (LTC, 12 °C for 3 days), this study investigated the effect of LTC on chilling tolerance and changes in antioxidant enzyme activities and endogenous hormones. RESULTS: LTC significantly alleviated chilling injury in kiwifruit. Fruits treated with LTC maintained lower respiration and ethylene production and higher firmness. Furthermore, this treatment inhibited the accumulation of malondialdehyde, superoxide radicals and hydrogen peroxide and the increase in membrane permeability and increased the activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase under chilling stress. The treatment also maintained higher levels of endogenous abscisic acid (ABA), indole-3-acetic acid (IAA) and zeatin riboside (ZR), lower gibberellic acid (GA3) levels and higher ABA/GA3 and ABA/IAA ratios. CONCLUSION: The results suggested that LTC alleviated chilling injury in kiwifruit by improving antioxidant enzyme activities and maintaining higher levels of endogenous ABA, IAA and ZR, lower GA3 levels and higher ABA/GA3 and ABA/IAA ratios.

Identification of xyloglucan endotransglucosylase/hydrolase genes (XTHs) and their expression in persimmon fruit as influenced by 1-methylcyclopropene and gibberellic acid during storage at ambient temperature.

Xyloglucan endotransglucosylase/hydrolase (XTH) is thought to contribute to fruit softening by degrading xyloglucan that is a predominant hemicellulose in the cell wall. In this study, two full-length XTH genes (DKXTH1 and DKXTH2) were identified from 'Fupingjianshi' persimmon fruit, and the expression level of both XTH genes was investigated during softening for 18-24 d using RT-qPCR. Sequence analysis showed that DKXTH1 and DKXTH2 contained a putative open reading frame of 861 and 876 bp encoding polypeptides of 287 and 292 amino acid residues, respectively, which contained the conserved DEIDFEFLG motif of XTH, a potential N-linked glycosylation signal site. RT-qPCR analysis showed that DKXTH1 and DKXTH2 in untreated fruit had different expression patterns during fruit softening, in which maximum expression occurred on days 3 and 12 of ripening, respectively. 1-Methylcyclopropene (1-MCP) and gibberellic acid (GA(3)) treatments delayed the softening and ethylene peak of persimmon fruit, as well as suppressed the expression of both XTH genes, especially DKXTH1. These results indicated that the expression of both XTH genes might be ethylene dependent action, and closely related to softening of persimmon in the early (DKXTH1) and later (DKXTH2) ripening stages.