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Harvested longan fruit is prone to pericarp browning, which restricts preservation quality and shortens fruit shelf life. The antioxidant system can defend against oxidative stress–mediated quality deterioration such as fruit browning. This study aimed to evaluate the effect of tert‐butylhydroquinone (TBHQ) on anti‐browning ability of longan fruit in association with redox metabolism. The results indicated that the application of 0.02% TBHQ significantly suppressed the progression of pericarp browning. In comparison with control, TBHQ treatment decreased the contents of hydrogen peroxide (H2O2), superoxide radical (O2−⋅), and malondialdehyde, and retained high levels of ascorbic acid (AsA), glutathione (GSH), total phenolics as well as 1,1‐diphenyl‐2‐picrylhydrazyl scavenging rate. Enhanced enzymatic activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase, and dehydroascorbate reductase (DHAR), but decreased activities of polyphenol oxidase and peroxidase were also observed in TBHQ‐treated fruit. Gene expression analysis indicated that redox metabolism‐related genes, including DlSOD, DlCAT, DlGR, and DlAPX, were upregulated after TBHQ treatment. Correlation analysis suggested that antioxidants, including AsA, GSH, CAT, APX, SOD, and DHAR, were negatively correlated to reactive oxygen species production and percarp browning. These results suggest that TBHQ is effective in alleviating pericarp browning by increasing antioxidant capacity of longan fruit. [ABSTRACT FROM AUTHOR]

Pericarp browning and fruit decay severely reduce the postharvest quality of litchi. Improving the antioxidant capacity of the fruit is an effective way to solve these problems. In our study, the appropriate zinc oxide nanoparticles (ZnO NPs) treatment and its mechanism of action on the storability of litchi was investigated. Litchi fruit was soaked in a 100 mg·L−1 ZnO NPs suspension, water, and 500 mg·L−1 prochloraz for 2 min, respectively. The results showed that the ZnO NPs treatment delayed pericarp browning and decay in litchi fruit and was more effective than prochloraz treatment. The ZnO NPs-treated fruit showed significantly increased contents of total anthocyanin, total phenols, and activities of DPPH scavenging, superoxide dismutase, and glutathione peroxidase, as well as the lowest activities of polyphenol oxidase and laccase. ZnO NPs generated hydrogen peroxide and superoxide anion radicals, which were beneficial in slowing down the decay and inducing antioxidant capacity. However, these reactive oxygen species also consumed catalase, peroxidase, glutathione, and glutathione peroxidase. This means that litchi should be treated with an appropriate concentration of ZnO NPs. We concluded that treatment with a 100 mg·L−1 ZnO NPs suspension could induce antioxidant capacity, which is a promising and effective method to maintain the postharvest quality of litchi. [ABSTRACT FROM AUTHOR]

To investigate the regulatory effect and possible mechanism of exogenous sodium nitroprusside (SNP) treatment on the pericarp browning of refrigerated ‘Nanguo’ pear fruit, the effect of 1.0 mmol/L SNP pretreatment on the pericarp browning of ‘Nanguo’ pear fruit during shelf life at room temperature after 180 days of refrigerated storage was investigated. The results showed that browning symptoms appeared in the SNP-treated fruit three days later than the control fruit, and at the end of the shelf life, the browning incidence and browning index were 41.8% and 31.9% of those of the control fruit, respectively. The treatment protected the structural integrity of pericarp cells and inhibited the elevation of membrane permeability. Further analysis revealed that at the end of the shelf life, the superoxide anion, hydroxyl and 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical scavenging capacity of the SNP-treated fruit were 1.65, 1.13, and 1.24 times higher than those of the control fruit, respectively. Meanwhile, the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) was significantly reduced, which was 25.2% and 32.8% lower than that of the control group, respectively, and the activities and gene expression of polyphenol oxidase and peroxidase were 17.5%, 28.8%, 37.5% and 39.2% lower than those of the control group, respectively. In addition, the synthesis of phenolics was inhibited to some extent. In conclusion, SNP treatment could alleviate the occurrence of pericarp browning in refrigerated ‘Nanguo’ pear fruit by inhibiting membrane lipid peroxidation and maintaining cellular structural integrity and function.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Oxidative damage leading to loss of nutritional quality and pericarp discoloration of harvested litchi fruits drastically limits consumer acceptance and marketability. In the present investigation, the impact of postharvest melatonin application at different concentrations, i.e., 0.1 mM, 0.25 mM, and 0.5 mM, on fruit quality and shelf life of litchi fruits under cold storage conditions was studied. The results revealed the positive effect of melatonin application at all concentrations on fruit quality and shelf life. However, treatment with 0.5 mM concentration of melatonin resulted in minimum weight loss, decay loss, pericarp discoloration, and also retained higher levels of TSS, acidity, total sugar, ascorbic acid, anthocyanin, antioxidant, and phenolics content during cold storage. Melatonin administration also restricted the enzymatic activity of the polyphenol oxidase (PPO) and peroxidase (POD) enzymes in the fruit pericarp and maintained freshness of the fruits up to 30 days in cold storage. At the molecular level, a similar reduction in the expression of browning-associated genes, LcPPO, LcPOD, and Laccase, was detected in preserved litchi fruits treated with melatonin. Anthocyanin biosynthetic genes, LcUFGT and LcDFR, on the other hand showed enhanced expression in melatonin treated fruits compared to untreated fruits. Melatonin, owing to its antioxidant properties, when applied to harvested litchi fruits retained taste, nutritional quality and red color pericarp up till 30 days in cold storage. [ABSTRACT FROM AUTHOR]

Effects of slightly acidic electrolyzed water (SAEW) on the storability, quality attributes, and reactive oxygen species (ROS) metabolism of litchis were investigated. Results showed that SAEW-treated litchis presented better quality attributes and storability than control litchis. On storage day 5, the commercially acceptable fruit rate of control litchis was 42%, while SAEW-treated litchis displayed 59% higher rate of commercially acceptable fruit, 21% lower pericarp browning index, and 13% lower weight loss percentage than control litchis. Additionally, compared to control litchis, SAEW-treated litchis demonstrated higher activities of SOD, CAT and APX, higher levels of GSH, AsA, DPPH radical scavenging ability, and reducing power, but lower O2−· generation rate, lower levels of H2O2 and MDA. These findings indicated that SAEW treatment could elevate antioxidant capacity and ROS scavenging ability, reduce ROS production and accumulation, and lower membrane lipid peroxidation, thereby retaining the quality attributes and storability of litchis.

Pericarp browning is the key factor for the extension of shelf life and the maintenance of the commercial value of harvested litchi fruit. Water loss is considered a leading factor of pericarp browning in litchi fruit. In this study, based on the distinct structure of litchi fruit, which is a special type of dry fruit with the aril as the edible part, the effects of water supply via pedicel (WSP) treatment on pericarp browning and the fruit quality of litchi were investigated. Compared with the packaging of the control fruit at 25 °C or 4 °C, the WSP treatment was found to significantly reduce pericarp browning and the decay of litchi fruit. The WSP-treated fruit had a higher L* value, total anthocyanin content, and pericarp water content, and the pericarp was thicker. The WSP treatment significantly suppressed the increase in the electrolyte leakage of the pericarp and maintained higher ascorbic acid (AA) contents in the aril. In addition, the WSP treatment was effective in reducing the activity and gene expression of browning-related genes Laccase (ADE/LAC) and Peroxidase (POD) during the storage period. In conclusion, the WSP treatment could be an effective method to delay pericarp browning and maintain the quality of harvested litchi fruit, and this further supports that litchi fruit has dry fruit characteristics. [ABSTRACT FROM AUTHOR]

Oxidative damage leading to loss of nutritional quality and pericarp discoloration of harvested litchi fruits drastically limits consumer acceptance and marketability. In the present investigation, the impact of postharvest melatonin application at different concentrations, i.e., 0.1 mM, 0.25 mM, and 0.5 mM, on fruit quality and shelf life of litchi fruits under cold storage conditions was studied. The results revealed the positive effect of melatonin application at all concentrations on fruit quality and shelf life. However, treatment with 0.5 mM concentration of melatonin resulted in minimum weight loss, decay loss, pericarp discoloration, and also retained higher levels of TSS, acidity, total sugar, ascorbic acid, anthocyanin, antioxidant, and phenolics content during cold storage. Melatonin administration also restricted the enzymatic activity of the polyphenol oxidase (PPO) and peroxidase (POD) enzymes in the fruit pericarp and maintained freshness of the fruits up to 30 days in cold storage. At the molecular level, a similar reduction in the expression of browning-associated genes, LcPPO, LcPOD, and Laccase, was detected in preserved litchi fruits treated with melatonin. Anthocyanin biosynthetic genes, LcUFGT and LcDFR, on the other hand showed enhanced expression in melatonin treated fruits compared to untreated fruits. Melatonin, owing to its antioxidant properties, when applied to harvested litchi fruits retained taste, nutritional quality and red color pericarp up till 30 days in cold storage.

Pericarp browning and fruit decay severely reduce the postharvest quality of litchi. Improving the antioxidant capacity of the fruit is an effective way to solve these problems. In our study, the appropriate zinc oxide nanoparticles (ZnO NPs) treatment and its mechanism of action on the storability of litchi was investigated. Litchi fruit was soaked in a 100 mg·L−1 ZnO NPs suspension, water, and 500 mg·L−1 prochloraz for 2 min, respectively. The results showed that the ZnO NPs treatment delayed pericarp browning and decay in litchi fruit and was more effective than prochloraz treatment. The ZnO NPs-treated fruit showed significantly increased contents of total anthocyanin, total phenols, and activities of DPPH scavenging, superoxide dismutase, and glutathione peroxidase, as well as the lowest activities of polyphenol oxidase and laccase. ZnO NPs generated hydrogen peroxide and superoxide anion radicals, which were beneficial in slowing down the decay and inducing antioxidant capacity. However, these reactive oxygen species also consumed catalase, peroxidase, glutathione, and glutathione peroxidase. This means that litchi should be treated with an appropriate concentration of ZnO NPs. We concluded that treatment with a 100 mg·L−1 ZnO NPs suspension could induce antioxidant capacity, which is a promising and effective method to maintain the postharvest quality of litchi.

In this research, we investigated the effects of treatment with different concentrations (10, 50 and 100 μmol/L) of methyl jasmonate (MeJA) on postharvest browning of ‘Chuliang’ longan fruit (Dimocarpus longan Lour.) during storage at (20 ± 1) ℃ and 85% relative humidity. The results showed that compared with the control fruit, MeJA treatment effectively reduced pericarp browning index, pericarp cell membrane permeability and pulp breakdown index in a concentration-dependent manner. In addition, 100 μmol/L MeJA maintained higher contents of total phenols and flavonoids, reduced the activity of polyphenol oxidase (PPO), and increased the activity of peroxidase (POD) and phenylalanine ammonialyase (PAL) in the pericarp. MeJA treatment could effectively reduce the rate of superoxide anion production and H2O2 content, enhance the activity of antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, and improve antioxidant capacity. Therefore, it is concluded that 100 μmol/L MeJA treatment can inhibit postharvest phenolic metabolism and increase antioxidant capacity in longan fruit, thus delaying pericarp browning and prolonging its storage.

Litchi (Litchi chinensis Sonn.) fruit deterioration occurs rapidly after harvest and is characterized by pericarp browning, pulp softening, and decay. In this study, we found that calcium chloride (CaCl2) treatment (5 g L−1 CaCl2 solution vacuum infiltration for 5 min) affected the cell wall component contents and cell wall-degrading enzyme activities of litchi fruit during storage at room temperature. CaCl2 treatment significantly increased the contents of Ca2+ and cellulose, while it decreased the water-soluble pectin content, and the activities of polygalacturonase, β-galactosidase, and cellulase in the litchi pericarp. Meanwhile, the treatment resulted in significantly increased contents of Ca2+, water-soluble pectin, ionic-soluble pectin, covalent-soluble pectin and hemicellulose, and upregulated activities of pectinesterase and β-galactosidase, while significantly decreasing the activities of polygalacturonase and cellulase in litchi pulp. The above results indicate that CaCl2 treatment strengthened the cell wall structure of litchi fruit. More importantly, the enzymatic browning of the pericarp, softening of the pulp, and disease incidence were delayed. The treatment had a more pronounced effect on the pericarp than on the pulp. We consider CaCl2 treatment to be a safe and effective treatment for maintaining the postharvest quality of litchi fruit. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study used polyethylene bags with thicknesses of 10, 20, and 30 µm to package "Jizuili" litchi, combined with ice bags to simulate logistics packaging, to study the effect on litchi peel browning, cell membrane permeability and anthocyanin metabolism under the current imperfect cold chain logistics system, in order to explore simple and efficient litchi fresh-keeping logistics technology for actual production. The results revealed that 20 μm polyethylene bags had better packaging effects, followed by 10 μm thickness, and the worst was 30 μm, by analyzing of pericarp browning, commercially acceptable rate and fruit color difference components during storage. And the 20 μm thickness polyethylene bags distinctly inhibited the increase in membrane permeability, which was reflected in the lower relative electrical conductivity of the fruit during storage (P

Rambutan (Nephelium lappaceum L.) (Sapinadeae) fruit, a nutritional staple in Hawaii, exhibits desiccation and physiological browning soon after harvest, and methods to prolong shelf life may be commercially advantageous. In this study, freshly harvested fruit were treated with pectin coatings with or without trans-cinnamaldehyde (TCIN) and stored at 10 °C or 20 °C (room temperature) to evaluate postharvest quality attributes. Control fruit were treated with deionized water only. To find the best formulation of the coatings, three concentrations of TCIN were incorporated into a pectin solution to get 0.05% TCIN, 0.1% TCIN, and 0.2% TCIN coatings. At 0, 2, 4, and 6 days postharvest, fruit stored at 20°C were evaluated for weight loss, firmness, pericarp browning, sugar, acid, and taste. The results showed that the 0.1% TCIN coating exhibited significantly lower weight loss than both control and the 0.2% TCIN coating through the entire storage time at 20°C. The 0.1% TCIN coating–treated fruit were significantly firmer than control after 4 days of storage at 20°C. The 0.1% TCIN coating also significantly reduced the pericarp browning over the control. Therefore, we selected 0.1% TCIN coating for fruit storage at 10°C for up to 15 days. At 10°C, the control fruit showed significantly higher pericarp browning than all TCIN-containing coated fruit. The 0.1% TCIN-treated fruit showed a significantly higher overall quality value than control fruit. The results indicate that the 0.1% TCIN coating may extend the commercial shelf life of rambutans and other perishable fruits. By extending shelf life, this coating can reduce postharvest losses and facilitate expanded fruit exports in Hawaii. [ABSTRACT FROM AUTHOR]

Rambutan (Nephelium lappaceum L.) (Sapinadeae) fruit, a nutritional staple in Hawaii, exhibits desiccation and physiological browning soon after harvest, and methods to prolong shelf life may be commercially advantageous. In this study, freshly harvested fruit were treated with pectin coatings with or without trans-cinnamaldehyde (TCIN) and stored at 10 °C or 20 °C (room temperature) to evaluate postharvest quality attributes. Control fruit were treated with deionized water only. To find the best formulation of the coatings, three concentrations of TCIN were incorporated into a pectin solution to get 0.05% TCIN, 0.1% TCIN, and 0.2% TCIN coatings. At 0, 2, 4, and 6 days postharvest, fruit stored at 20 °C were evaluated for weight loss, firmness, pericarp browning, sugar, acid, and taste. The results showed that the 0.1% TCIN coating exhibited significantly lower weight loss than both control and the 0.2% TCIN coating through the entire storage time at 20 °C. The 0.1% TCIN coating–treated fruit were significantly firmer than control after 4 days of storage at 20 °C. The 0.1% TCIN coating also significantly reduced the pericarp browning over the control. Therefore, we selected 0.1% TCIN coating for fruit storage at 10 °C for up to 15 days. At 10 °C, the control fruit showed significantly higher pericarp browning than all TCIN-containing coated fruit. The 0.1% TCIN-treated fruit showed a significantly higher overall quality value than control fruit. The results indicate that the 0.1% TCIN coating may extend the commercial shelf life of rambutans and other perishable fruits. By extending shelf life, this coating can reduce postharvest losses and facilitate expanded fruit exports in Hawaii.

Although the effects of phytohormones (mainly salicylic acid) on the storability of longan fruit have been reported, the relationship between postharvest hormone variation and signal transduction and storability remains unexplored. The basis of physiology, biochemistry, hormone content and signalling for the storability difference at room-temperature between 'Shixia' and 'Luosanmu' longan fruit were examined. 'Luosanmu' longan exhibited faster pericarp browning, aril breakdown and rotting during storage. 'Luosanmu' pericarp exhibited higher malondialdehyde but faster decreased total phenolics, flavonoid, glutathione, vitamin C, catalase activity and gene expression. Higher H2O2 and malondialdehyde but lower glutathione, glutathione-reductase and peroxidase activities, while higher activities and gene expressions of polygalacturonase, β-galactosidase and cellulose, lower covalent-soluble pectin, cellulose and hemicellulose but higher water-soluble pectin were observed in 'Luosanmu' aril. Lower abscisic acid and methyl jasmonate but higher expressions of LOX2, JAZ and NPR1 in pericarp, while higher abscisic acid, methyl jasmonate and salicylic acid together with higher expressions of ABF, JAZ, NPR1 and PR-1 in 'Luosanmu' aril were observed. In conclusion, the imbalance between the accumulation and scavenging of active oxygen in 'Luosanmu' longan might induce faster lipid peroxidation and senescence-related hormone signalling and further the polymerization of phenolics in pericarp and polysaccharide degradation in aril. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis Sonn.) fruit deterioration occurs rapidly after harvest and is characterized by pericarp browning, pulp softening, and decay. In this study, we found that calcium chloride (CaCl2) treatment (5 g L−1 CaCl2 solution vacuum infiltration for 5 min) affected the cell wall component contents and cell wall-degrading enzyme activities of litchi fruit during storage at room temperature. CaCl2 treatment significantly increased the contents of Ca2+ and cellulose, while it decreased the water-soluble pectin content, and the activities of polygalacturonase, β-galactosidase, and cellulase in the litchi pericarp. Meanwhile, the treatment resulted in significantly increased contents of Ca2+, water-soluble pectin, ionic-soluble pectin, covalent-soluble pectin and hemicellulose, and upregulated activities of pectinesterase and β-galactosidase, while significantly decreasing the activities of polygalacturonase and cellulase in litchi pulp. The above results indicate that CaCl2 treatment strengthened the cell wall structure of litchi fruit. More importantly, the enzymatic browning of the pericarp, softening of the pulp, and disease incidence were delayed. The treatment had a more pronounced effect on the pericarp than on the pulp. We consider CaCl2 treatment to be a safe and effective treatment for maintaining the postharvest quality of litchi fruit.

Pericarp browning (PB) is a serious problem in harvested litchi and drastically affects consumer acceptability and marketability. Postharvest PB and subsequent decay in fruit are linked to reactive oxygen species (ROS) accumulation in tissues. Antioxidants neutralize or scavenge ROS and maintain the shelf-life of fruit, especially in non-climacteric ones such as litchi. This work was aimed to assess the effect of vacuum infiltrated methyl jasmonate (MeJA; 1 and 2 mM) on the quality of harvested litchi fruit (cv. Purbi) during ambient storage (28 °C, RH 70–75%). The exogenous MeJA infiltration (2 mM) significantly retained quality attributes of litchi fruit as evident by lowered PB, weight loss, disease occurrence, quinone, and ROS (H2O2 and O2−) accumulation. Moreover, MeJA infiltrated fruit suppressed the activity of polyphenol oxidase and peroxidase resulting in higher anthocyanin, phenolics, antioxidant potential, phenylalanine ammonia lyase activity as well as membrane integrity throughout the storage. Control fruit showed an early quality deterioration marked by prominent PB and other biochemical degradative changes. Thus, exogenous MeJA infiltration (2 mM) could be suggested to increase the shelf life of litchi by four days under ambient conditions. [ABSTRACT FROM AUTHOR]

The effects of 50 mg L−1 GA 3 spraying at 65+75 days after flowering (DAF) (GA 3 _a), 75+85 DAF (GA 3 _b) and 85+95 DAF (GA 3 _c) on the room-temperature storability were compared to screen the ideal treatment time-points. GA 3 _b significantly inhibited the increasing of mass loss, rotting, aril breakdown, electrolyte leakage and pericarp browning. More importantly, GA 3 _b enhanced ROS-scavenging capacity through up-regulating activities of PAL (phenylalanine ammonia-lyase), CAT (catalase) and APX (ascorbate peroxidase), therefore reduced H 2 O 2 and malondialdehyde, retained phenolics, chlorophylls and carotenoid in pericarp at the later storage stages. GA 3 _b significantly inhibited pericarp enzymatic-browning by down-regulating expression and activities of POD (peroxidase), PPO (polyphenol oxidase) and LAC (laccase) and postharvest flavan-3-ols' polymerization. Moreover, GA 3 _b up-regulated GA 3 , SA and MeJA content at ripening & earlier storage, inhibited ABA biosynthesis at 85 DAF, up-regulated postharvest expression of NCED (9-cis-epoxycarotenoid dioxygenase) , ABF (Abscisic acid-insensitive 5-like protein) , NPR1 (non-expresser of pathogenesis related [PR] 1) expression but down-regulated PR1 (pathogen-related protein 1) and might promote survival of pericarp cell. In summary, 50 mg L−1 GA 3 spraying at 75+85 DAF was an ideal treatment to effectively improved the storability of longan fruit through enhancing ROS-scavenging capacity, inhibiting enzymatic-browning and promoting the survival of pericarp cell by reprogramming phytohormone. [Display omitted] • The best room-temperature storability was obtained by 50 mg/L GA 3 spray at 75+85 DAF. • Mass loss, rotting, electrolyte leakage, aril breakdown & pericarp browning decreased. • H 2 O 2 and MDA were reduced while phenolics, chlorophylls, and carotenoid were retained. • Activities of POD, PPO, and laccase and flavan-3-ols' polymerization were inhibited. • Reprogrammed variation and signaling of phytohormone might rescue pericarp cell. [ABSTRACT FROM AUTHOR]

Pericarp browning is a major symptom of the quality deterioration in postharvest longan fruit. Previous studies show that the change in the quality of fresh produce is related to the level of energy status. The proton transport regulator such as dicyclohexylcarbodiimide (DCC) and disodium succinate (DS) can regulate the protons flux to affect the production of adenosine triphosphate (ATP) and the level of energy status. However, the mechanisms of proton transport regulator induced-the changes in the level of ATP and energy status in postharvest longan fruit in relation to longan pericarp browning remain unclear. In this work, the influences of DCC and DS-mediated the alteration of energy status on longan pericarp browning, energy metabolism, and respiratory metabolism were investigated. Results showed that DCC treatment accelerated pericarp browning development and elevated respiration rate as compared to the control. Longans treated with DCC exhibited higher levels of ATP, adenosine diphosphate (ADP), and energy charge, as well as higher activities of H+-ATPase, Ca2+-ATPase, and Mg2+-ATPase in the mitochondrial, vacuole, and plasma membranes. Additionally, DCC treatment increased the activities of phosphoglucose isomerase (PGI), succinate dehydrogenase (SDH), cytochrome C oxidase (CCO), ascorbic acid oxidase (AAO), and alternative oxidase (AOX), along with higher contents of ubiquinol (QH 2), nicotinamide adenine dinucleotide (NAD), and the reduced form of NAD (NADH). Whereas, DCC treatment decreased the activities of nicotinamide adenine dinucleotide kinase (NADK), and glucose-6-phosphate dehydrogenase (G-6-PDH) + 6-phosphaogluconate dehydrogenase (6-PGDH), and lowered the contents of ubiquinone (Q), nicotinamide adenine dinucleotide phosphate (NADP), and the reduced form of NADP (NADPH). These results revealed that DCC treatment accelerated energy deficit, disrupted energy balance, and promoted respiratory metabolism through enhancing embden-meyerhof-parnas (EMP), tricarboxylic acid (TCA) cycle, and cytochrome pathway (CCP) while attenuating pentose phosphate pathway (PPP), ultimately leading to the aggravated longan pericarp browning. Conversely, DS treatment delayed longan pericarp browning by acting on the opposite effects of DCC treatment. • DCC hastened longan pericarp browning, whereas DS had the opposite effect. • DCC lowered energy status of longan pericarp, but DS retained a higher energy status. • DCC reduced ATPase activities in longan pericarp, but DS enhanced these activities. • DCC raised EMP-TCA cycle and CCP, but reduced PPP, DS exhibited the opposite pattern. • DCC speeded energy deficit and respiratory metabolism, but DS retarded this process. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Litchi fruit contains abundant polyphenols and is susceptible to browning after harvest. Herein the combined treatments of malic acid (MA) and lycopene (LYC) to delay the development of browning in litchi fruit stored at room temperature (25°C) and low temperature (4°C) was investigated. The results showed that the pericarp browning could be alleviated, and the increase of malondialdehyde (MDA) content and relative leakage rate was retarded by the combined MA and LYC during storage. As compared to control, the content of pericarp anthocyanins, flavonoids, and the total phenols maintained higher levels; and the decrease of antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and reducing power were slowed down in treated fruit. The enzyme activity of polyphenol oxidase (PPO) and peroxidase (POD) related to oxidation of polyphenols were depressed by the combined treatments. Furthermore, correlation analysis revealed that the content of phenols in the pericarp negatively affected the changes in the browning index, and was positively related to the DPPH radical scavenging capacity. Taken together, the combined treatments of MA and LYC exhibited potential effects in delaying the pericarp browning of litchi fruit by maintaining the content of polyphenols, antioxidant activity, and membrane integrity.

Postharvest pericarp browning (PB) drastically affects acceptability and marketability of litchi fruits. This study was aimed to assess the effect of vacuum infiltrated hydrogen sulfide (H2S) (1 and 2 mM) on pericarp browning associated metabolism and overall quality of litchi fruit during cold storage. Results revealed that H2S (2 mM) significantly minimized the accumulation of quinone and MDA content with reduced weight loss, pericarp browning, disease occurrence during storage. The H2S-treated fruits maintained higher anthocyanin, total phenols, and antioxidant activity. Moreover, H2S infiltration significantly inhibited accumulation of reactive oxygen species (superoxide and hydrogen peroxide) and membrane leakage, which coincided with higher phenylalanine ammonia lyase activity and suppressed activity of polyphenol oxidase and peroxidase resulting in lower PB in litchi during storage of 16-d. H2S infiltration also prevented loss of TSS, acidity, and ascorbic acid as compared to control fruit indicating effectiveness of H2S in delaying metabolic activity. Therefore, postharvest vacuum infiltration of H2S (2 mM) could be suggested to downregulate oxidative damage and PB resulting in extended shelf life during cold storage. [ABSTRACT FROM AUTHOR]

The impacts of reactive oxygen species (ROS) scavenger ascorbic acid (AsA) treatment on the storability and quality attributes of ‘Fuyan’ longan fruit were explored. Compared to control samples, the treatment of 4 g L−1 AsA solution clearly reduced fruit weight loss, indexes of fruit disease and pericarp browning, retained higher percentage of commercially acceptable fruit, higher values of chromaticity a∗, chromaticity b∗, and chromaticity L∗, delayed pigment degradation in longan pericarp, and retarded the decreases of nutritive ingredients in longan pulp. When stored for 6 d, vitamin C (0.08 g kg−1), sucrose (20.70 g kg−1), total soluble sugar (56.32 g kg−1), and total soluble solids (12.4%) in AsA-treated fruit displayed the clearly higher contents than those in control samples. These data suggested that the treatment of exogenous ROS scavenger AsA could effectively enhance the quality attributes and storability of postharvest longan fruit, thereby lengthen their postharvest shelf-life.

Effects of slightly acidic electrolyzed water (SAEW) on the storability, quality attributes, and reactive oxygen species (ROS) metabolism of litchis were investigated. Results showed that SAEW-treated litchis presented better quality attributes and storability than control litchis. On storage day 5, the commercially acceptable fruit rate of control litchis was 42%, while SAEW-treated litchis displayed 59% higher rate of commercially acceptable fruit, 21% lower pericarp browning index, and 13% lower weight loss percentage than control litchis. Additionally, compared to control litchis, SAEW-treated litchis demonstrated higher activities of SOD, CAT and APX, higher levels of GSH, AsA, DPPH radical scavenging ability, and reducing power, but lower O 2 -· generation rate, lower levels of H 2 O 2 and MDA. These findings indicated that SAEW treatment could elevate antioxidant capacity and ROS scavenging ability, reduce ROS production and accumulation, and lower membrane lipid peroxidation, thereby retaining the quality attributes and storability of litchis., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Postharvest melatonin treatments have been reported to improve the quality and storability, especially to inhibit browning in many fruits, but the effect had not been systematically investigated on longan fruit. In this study, the effect of 0.4 mM melatonin (MLT) dipping on the quality and pericarp browning of longan fruits stored at low temperature was investigated. The MLT treatment did not influence the TSS content of longan fruits but lead to increased lightness and h° value while decreased a* value of pericarp. More importantly, the treatment significantly delayed the increase in electrolyte leakage and malonaldehyde accumulation, inhibited the activities of polyphenol oxidase and peroxidase, and thus retarded pericarp browning. In addition, the treatment significantly inhibited the production of O2•− and H2O2 while promoted the accumulation of glutathione, flavonoids, and phenolics at earlier storage stages in longan pericarp. Interestingly, the activities of ascorbate peroxidase (APX) and superoxide dismutase (SOD) were significantly upregulated but activities of catalase were downregulated in the MLT‐treated longan pericarp. MLT treatment effectively enhanced APX and SOD activities, increased flavonoid, phenolics, and glutathione content, protected cytomembrane integrity, inhibited the production of O2•− and H2O2 and browning‐related enzymes, and thus delayed the longan pericarp browning. [ABSTRACT FROM AUTHOR]

Pericarp browning occurs widely in postharvest pomegranate fruit, but little is known about its mechanism. In this study, ‘Baiyushizi’, a browning-sensitive cultivar, was used to investigate the physiological and genetic changes during pericarp browning. The pericarp browning index (BI) increased greatly after 3 d storage at room temperature, and, consequently, the fruit appearance became unattractive after 6 d. The increasing concentration of malondialdehyde (MDA) and electrolyte leakage were detected in browning pericarp. Polyphenol oxidase (PPO) activity increased significantly after 3 d, while ascorbate peroxidase (APX) and catalase (CAT) activity decreased steadily during storage. Total phenolics content decreased gradually during storage, while ascorbic acid (AsA) and glutathione (GSH) contents increased firstly, then declined. Differentially expressed genes (DEGs) of pericarp under different browning degrees were identified in the metabolic processes of phenolic compounds, lipids, ascorbic acid, glutathione, sugar, starch, energy-related, ethylene biosynthesis and signal transduction pathways. Accordingly, the potential metabolic pathways and related processes involved in pericarp browning were described. The results not only provided insights on the genetic mechanism of pericarp browning in pomegranate but also guidance on controlling postharvest fruit browning in general.

Although the effects of phytohormones (mainly salicylic acid) on the storability of longan fruit have been reported, the relationship between postharvest hormone variation and signal transduction and storability remains unexplored. The basis of physiology, biochemistry, hormone content and signalling for the storability difference at room-temperature between ‘Shixia’ and ‘Luosanmu’ longan fruit were examined. ‘Luosanmu’ longan exhibited faster pericarp browning, aril breakdown and rotting during storage. ‘Luosanmu’ pericarp exhibited higher malondialdehyde but faster decreased total phenolics, flavonoid, glutathione, vitamin C, catalase activity and gene expression. Higher H2O2 and malondialdehyde but lower glutathione, glutathione-reductase and peroxidase activities, while higher activities and gene expressions of polygalacturonase, β-galactosidase and cellulose, lower covalent-soluble pectin, cellulose and hemicellulose but higher water-soluble pectin were observed in ‘Luosanmu’ aril. Lower abscisic acid and methyl jasmonate but higher expressions of LOX2, JAZ and NPR1 in pericarp, while higher abscisic acid, methyl jasmonate and salicylic acid together with higher expressions of ABF, JAZ, NPR1 and PR-1 in ‘Luosanmu’ aril were observed. In conclusion, the imbalance between the accumulation and scavenging of active oxygen in ‘Luosanmu’ longan might induce faster lipid peroxidation and senescence-related hormone signalling and further the polymerization of phenolics in pericarp and polysaccharide degradation in aril.

Postharvest litchi fruit is highly perishable and vulnerable to pericarp browning (PB), which affects marketability. In this study, the effect of vacuum infiltrated methyl jasmonate (0, 1, or 2 mM) on the quality of fresh cold stored (7 ± 1 °C and RH 85–90%) litchi. The MeJA effectively reduced PB and increased storage life up to 16 d by retaining higher fruit weight, soluble solids, acidity, and anthocyanin contents. MeJA (2 mM) treated fruits maintained higher levels of phenols, ascorbic acid and antioxidant activity. Moreover, the accumulation of reactive oxygen species (superoxide anion and hydrogen peroxide), membrane permeability, lipid peroxidation, and quinone was downregulated. The MeJA treatment also reduced the activity of PPO and POD as well as maintained higher PAL activity with delayed PB in litchi. Therefore, the MeJA infiltration (2 mM) could be suggested to enhance the storability of litchi fruits during cold storage.

Methyl jasmonate (MeJA) is an important bioactive metabolite in fruits and vegetables that regulates various physiological processes. The effects of MeJA on pericarp browning in longan fruit and its underlying mechanism were investigated. Results showed that treatment with 100 μM MeJA substantially suppressed the development of pericarp browning in harvested longan fruit. Compared to untreated fruit, MeJA-treated fruit exhibited reduced cell membrane permeability during storage. Meanwhile, MeJA-treated fruit displayed lower levels of phosphatidic acid and higher content of phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol, and phosphatidylethanolamine through suppressing the activities of key enzymes involved in membrane lipids metabolism, such as phospholipases, lipase and lipoxygenase. Furthermore, MeJA treatment enhances the energy status of the fruit, evidenced by elevated the levels of adenosine triphosphate and energy charge. This effect could be attributed to the enhanced activities of various energy metabolism enzymes. Overall, all results suggest that MeJA is a promising agent for inhibiting pericarp browning in longan fruit through modulation of membrane lipid and energy metabolisms. • Methyl jasmonate (MeJA) inhibits pericarp browning in longan fruit during storage. • MeJA treatment prevents the accumulation of phosphatidic acid in longan fruit. • MeJA treatment reduces the activity of enzymes involved in membrane lipid metabolism. • MeJA treatment maintains a higher energy status in longan fruit during storage. • MeJA treatment enhances the activities of energy metabolism enzymes in longan fruit. [ABSTRACT FROM AUTHOR]

Long-term storage of pear fruit at low temperature can retard senescence but may result in pericarp browning. We previously reported that increasing endogenous γ-aminobutyrate (GABA) content by exogenous GABA treatment can maintain mitochondrial structure integrity, thereby alleviating pericarp browning of ‘Nanguo’ pears after cold storage. Here, we tested the effectiveness of Ca2+ treatment on pericarp browning in relation to GABA biosynthesis. Fruit browning was reduced by treatment with Ca2+ after 180 days of storage. Pericarp Ca2+ and calmodulin content in treated fruit increased, and concomitantly, endogenous GABA content, key GABA synthesis-related enzyme activity, and gene expression were upregulated. Moreover, the mitochondrial structure in the pericarp tissue was found to be well preserved. Thus, Ca2+ treatment effectively reduced pericarp browning of refrigerated ‘Nanguo’ pears owing to improvement in the GABA biosynthesis capacity in the fruit.

Long-term storage of pear fruit at low temperature can retard senescence but may result in pericarp browning. We previously reported that increasing endogenous γ-aminobutyrate (GABA) content by exogenous GABA treatment can maintain mitochondrial structure integrity, thereby alleviating pericarp browning of 'Nanguo' pears after cold storage. Here, we tested the effectiveness of Ca2+ treatment on pericarp browning in relation to GABA biosynthesis. Fruit browning was reduced by treatment with Ca2+ after 180 days of storage. Pericarp Ca2+ and calmodulin content in treated fruit increased, and concomitantly, endogenous GABA content, key GABA synthesis-related enzyme activity, and gene expression were upregulated. Moreover, the mitochondrial structure in the pericarp tissue was found to be well preserved. Thus, Ca2+ treatment effectively reduced pericarp browning of refrigerated 'Nanguo' pears owing to improvement in the GABA biosynthesis capacity in the fruit. [ABSTRACT FROM AUTHOR]

Wampee fruit is a popular fruit cultivar in South‐East Asia due to its high levels of nutrients and antioxidants; however, pericarp browning leads to a short storage life with great economic loss during years. The purpose of this work was to determine whether postharvest ethanol fumigation affected pericarp browning development of wampee fruit during 12 days of storage at 8 ± 0.5°C, and if so, how it is related to phenol metabolism and how it affects quality attributes and antioxidant systems during storage. After fruits were fumigated with 100, 300, 500, and 800 μl/L for 5 hr at 22 ± 0.5°C, ethanol significantly reduced the development of pericarp browning by increasing total phenolics (TP) content and decreasing the activity of polyphenol oxidase (PPO), especially in 500 μl/L ethanol treatment. Additionally, ethanol delayed the losses in fruit firmness (FF), soluble solid content (SSC), and titratable acidity (TA), retarded weight loss and accumulation of malondialdehyde (MDA) content and maintained relatively high contents of ascorbic acid (AsA), total flavonoids (TF), and total antioxidant capacity (TAC) and activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). In conclusion, results demonstrated that postharvest ethanol fumigation in wampee fruit has ability to reduce pericarp browning development by regulating phenol metabolism and enhancing antioxidant systems. [ABSTRACT FROM AUTHOR]

Litchi fruits are highly perishable in nature and start deteriorating immediately after harvest, which can be characterized by pericarp browning. In this study, the effect of exogenous hydrogen sulfide (H2S) on different biochemical events linked to pericarp browning and oxidative damage in litchi were assessed at 1 day interval during 4 days storage. Fruits were vacuum infiltrated with H2S (1 and 2 mM) at ambient temperature. The untreated control fruits were subjected to dipping in distilled water and were stored at ambient (28 °C, RH 70–75%) conditions. H2S treatment maintained the postharvest quality of litchi fruit during storage by alleviating oxidative damage and modulating enzymatic activities. Control fruits lost their postharvest quality at initial storage with visible pericarp browning and other biochemical degradative changes when compared with treated fruits. Postharvest H2S (2 mM) infiltration significantly reduced weight loss, pericarp browning and ROS production (H2O2 and O2−) as well as suppressed the activity of polyphenol oxidase (PPO) and peroxidase (POD) enzymes and exhibited higher TSS, titratable acidity, total phenolic, anthocyanin, antioxidant activities, membrane integrity, phenylalanine ammonia lyase (PAL) activity and reduced quinone and malondialdehyde (MDA) accumulation. Thus, H2S (2 mM) infiltration treatment could be suggested to enhance the storage life of litchi fruits at ambient storage condition. [ABSTRACT FROM AUTHOR]

Pericarp browning is the main factor to reduce the storage life and marketability of longan fruit. In the present study evaluated chlorine dioxide (ClO2) dipping on reducing pericarp browning. Fresh longan fruit was dipped in 1%, 1.25% and 1.5% ClO2 for 5 min and stored at 5±2 oC, 85±5% RH for 42 days, investigated every 7 days. Evaluation by browning index (BI) as pericarp browning, outer pericarp color by a chromameter expressed as L*and b* value and hue angle, disease incidence, ClO2 residue and sensory acceptance was determined. The result showed that dipping in 1%, 1.25% and 1.5% ClO2 could reduce pericarp browning (lower BI, higher L* and b* value and hue angle). However, they showed no significant differences with commercial SO2 fumigation but they were significant differences with untreated fruit. ClO2 treatments could reduce disease incidence and low ClO2 residue in flesh. The sensory acceptance such as outer pericarp color, flesh and flavor treated with 1.5% ClO2 had shown great potential. The results suggested that 1.5% ClO2 dipping could reduce pericarp browning of longan fruit as same as the commercial SO2 fumigation. [ABSTRACT FROM AUTHOR]

Summary: An integrated control strategy on preventing pericarp browning (BI) and decay incidence (DI) of longan fruit was investigated to replace sulphur dioxide (SO2) fumigation. Fruit was treated with 5% ascorbic acid (AA), citric acid (CA), oxalic acid (OA), thymol (TH) and 2% chitosan (CH) for 5 min; sealed under modified atmosphere packaging (MAP) using high permeable film; and stored at 5 °C. Fruit treated with distilled water and sealed under MAP condition (MAPC) and air condition (AIRC) was used as controls. Combined effects of chemical treatments and MAP maintained quality of longan for 56 and 49 days in CH and TH, respectively, as compared to 28 days in MAPC and 21 days in AIRC. AA, CA and OA prevented BI, restrained enzyme activities and maintained high phenols. AA, CA and OA were most potent BI inhibitors; however, DI was the limitation of these treatments, while CH and TH effectively inhibited DI. [ABSTRACT FROM AUTHOR]

Ca2+ ATPase is essential for plant senescence, but its function and modulation in litchi remain largely unknown. Exogenous ATP treatment effectively alleviated litchi pericarp browning, and promote Ca2+ ATPase activity. The change of Ca2+ ATPase activity was negatively correlated with browning index (BI) and was positively correlated with ATP content during storage, demonstrating its positive roles in energy homeostasis and in delaying litchi senescence. The 14 litchi Ca2+ ATPase coding genes were comprehensively characterized, including ten LcACAs and four LcECAs. Expression profiles of Ca2+ ATPase coding genes in four litchi cultivars with different storability suggested that litchi cultivars with higher LcACAs expression achieved better storability. Additionally, LcACA2 was identified as a target of LcmiR482e by in vivo experiment and degradome, exhibiting opposite expression pattern to LcmiR482e during storage. Furthermore, ATP application remarkably downregulated LcmiR482e expression, contributing to the delayed senescence. This study provides new insights into Ca2+ ATPase-mediated litchi energy metabolism and senescence especially in miRNA regulation aspect. • Ten LcACAs and four LcECAs were identified as Ca2+ ATPase genes in litchi genome. • Ca2+ ATPase plays positive roles in energy homeostasis and litchi storability. • LcACA2 was firstly identified and validated as the target of LcmiR482e. • Downregulation of LcmiR482e-LcACA2 module delayed litchi senescence. [ABSTRACT FROM AUTHOR]

Energy transport system plays a pivotal role in maintaining cellular energy status. The adenine nucleotide translocator (ANT) family includes ATP/ADP carrier (AAC) and ATP/AMP translocator (ADNT). This research aims to illuminate the role of energy transport in pericarp browning process of postharvest longans. The results elucidated that the ATP content decreased with longan pericarp browning, and was positively correlated with expression levels of DlAAC1 and DlAAC5. Besides, the bongkrekic acid (BKA) treatment, which has a strong energy transport inhibitory property, could down-regulate the expressions of DlANTs , maintain lower energy level and activities of Ca2+-ATPase, Mg2+-ATPase and H+-ATPase in membranes of plasmas, mitochondria and vacuoles, and hasten the browning development of postharvest longan. While the ATP treatment kept higher expression levels of DlANTs , higher energy level and ATPase activities, and reduced the occurrence of longan pericarp browning. These findings suggested that the expression of DlANTs was regulated by energy status, and the inhibition of energy transport could lead to the reduction of energy level, the decreased ATPase activities, the down-regulated expressions of DlANTs , which might cause energy deficiency and thus accelerated pericarp browning of harvested longan fruit. [Display omitted] • The inhibition of energy transport accelerated the browning of longan. • The inhibition of energy transport induced the energy deficiency of longan. • The inhibition of energy transport accelerated the reduction of ATPase activities. • Energy status affected the expression characteristics of DlANTs. • The DlAAC1 and DlAAC5 might play key roles in energy transport of longan. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bacillus siamensis inhibits pericarp browning in litchi fruit by reducing LAC and PPO activity. • B. siamensis enhances ATP, ADP and energy charge levels in litchi fruit. • B. Siamensis enhances Ca2+-ATPase, H+-ATPase, CCO, and SDH activity and LcVHA2/3 expression. • LcVHA2 and LcVHA3 positively regulate energy levels in litchi fruit and as a result delay senescence. Pericarp browning, postharvest disease, and a short storage life are the leading causes of economic losses in the litchi industry globally. Energy metabolism plays an integral role in regulating browning, disease resistance, and the shelf-life of litchi fruit. The ability of Bacillus siamensis (N-1) to control postharvest diseases and maintain the quality of a variety of tropical fruits has previously been reported, however its effect on litchi fruit has not been explored. In the present study, we investigated the effect of Bacillus siamensis (N-1) on the postharvest energy metabolism of litchi fruit and its relation to pericarp browning, as well as the expression of energy-related genes. Results indicated that litchi fruit treated with Bacillus siamensis (N-1) exhibited a significant improvement in storability as evidenced by a decrease in the rate of the browning index (BI), color change, rate of weight loss, and laccase (LAC) and polyphenol oxidase (PPO) activity. There was also an increase in the energy status of litchi fruit due to the enhanced activity of Ca2+-ATPase, H+-ATPase, oxidase (CCO), cytochrome C , and succinic dehydrogenase (SDH), as well as the expression of their corresponding genes. LcVHA2 and LcVHA3 , two major vacuolar-type H+-ATPase genes, were cloned and characterized. Phylogenetic analysis revealed that these genes are members of the V-ATPase subunit D and E gene family, respectively. Both heterologous (in tomato) and homologous (in litchi) transient overexpression (OE) assays indicated that both LcVHA2 and LcVHA3 have the potential to delay changes in fruit coloration and pericarp browning, but also increase ADP, ATP, and V-H+-ATPase activity, as well as the energy charge (EC) of fruit. Collectively, results indicated that the LcVHA2 and LcVHA3 play a critical role in preventing the browning and senescence of litchi fruit. This study provides new information on the ability of Bacillus siamensis (N-1), which has been previously demonstrated to be an effective postharvest biocontrol agent, to also improve the storage life of litchi fruit. [ABSTRACT FROM AUTHOR]

The postharvest quality of rambutan fruits (Nephelium lappaceum Linn.) is mainly influenced by dehydration, which causes browning of the peel and spinterns. This research investigated the effects of some essential oils—from citronella, clove, kaffir lime, and lemongrass—on ‘Rongrien’ rambutan fruit quality during storage at 13 °C. Screening of effective concentrations from 0.01 to 0.16% was conducted for each essential oil. The results showed that, of the essential oil treatments tested, a kaffir lime oil coating of 0.01% could best maintain the quality of fruits, reducing both weight loss and browning of the peel and spinterns. However, essential oil concentrations exceeding 0.04% severely damaged the fruit pericarp, in which scores of spintern browning were higher than those of peel browning. These results suggest that kaffir lime oil can maintain the postharvest quality of ‘Rongrien’ rambutan fruit as a supplement in some edible coatings.

Pericarp browning is the major cause of deterioration of harvested litchi fruit. Water loss plays a role in pericarp browning of litchi fruit. This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature. Litchi fruit were stored in a non-humidified cold chamber (control) or in a humidified cold room using Tabor atomizer system that generated 95% relative humidity (RH) without depositing water on the fruit surface at 4°C. Control fruit stored in cold room without added humidity underwent rapid weight loss, accompanied by severe pericarp browning after 25 d of storage. However, slight weight loss and no obvious pericarp browning were found in humidified-fruit. Moreover, humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage. In addition, respiration rate was obviously inhibited in humidified-fruit compared with control fruit. This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film. [ABSTRACT FROM AUTHOR]

• Exogenous cytokinin treatment, applied during litchi pericarp cell division, result in mature fruit with thicker pericarp, reduced rate of post-harvest water loss and reduced susceptibility to post-harvest pericarp browning. • Cytokinin application prior to the onset of litchi fruit maturation inhibits fruit pericarp color change, but does not postpone aril maturation as implies from the rate of sugar accumulation and acid degradation. • During litchi fruit development, the timing of cytokinin application induce cell-type specific proliferation leading to differential effect on fruit pericarp anatomy. Litchi (Litchi chinensis Sonn.) is a subtropical fruit known for its attractive red pericarp color, semi-translucent white aril and unique flavor and aroma. Rapid post-harvest pericarp browning strictly limits litchi fruit marketing. In the current research, we hypothesized that modification of litchi fruit pericarp anatomy by hormone application may reduce fruit susceptibility to post-harvest pericarp browning. In this context, we hypothesized that cytokinin treatment, known to induce cell division, may yield fruit with thicker pericarp and reduced susceptibility for fruit surface micro-crack formation, water loss and post-harvest pericarp browning. Exogenous cytokinin treatment was applied at different stages along the course of litchi fruit development and the effect on fruit pericarp anatomy, fruit maturation and postharvest pericarp browning was investigated. Interestingly, cytokinin treatment, applied 4 weeks after full female bloom (WFB), during the phase of pericarp cell division, led to mature fruit with thicker pericarp, reduced rate of post-harvest water loss and reduced susceptibility to post-harvest pericarp browning, as compared to non-treated control fruit. Histological sections ascribe the difference in pericarp anatomy to increased cell proliferation in the parenchymatic tissue and the highly-lignified brachysclereid cell layer. In contrast, exogenous cytokinin treatment applied 7 WFB, following the phase of pericarp cell division, significantly increased epidermal-cell proliferation but had no significant effect on overall fruit pericarp thickness and only minor affect on post-harvest water loss or pericarp browning. Interestingly, the late cytokinin treatment also significantly postponed fruit maturation-associated anthocyanin accumulation and chlorophyll degradation, as previously reported, but had no effect on other parameters of fruit maturation, like total soluble sugars and total titratable acids typically modified during aril maturation. In conclusion, exogenous cytokinin treatment at different stages in fruit development differentially modifies litchi fruit pericarp anatomy by induction of cell-type specific cell proliferation. Early cytokinin treatment during the phase of pericarp cell division may prolong litchi fruit storage by reducing fruit susceptibility to post-harvest water loss and pericarp browning. [ABSTRACT FROM AUTHOR]

The pericarp browning is an important physiological index during the postharvest storage, which seriously shortens the shelf-life of litchi fruit. In this study, the browning index of four litchi cultivars were compared, and the shelf-life, from longer to shorter, was 'Feizixiao (FXZ)', 'Jingganghongnuo (JGHN)', 'Huaizhi (HZ)' and 'Nuomici (NMC)', respectively. Then, comparative metabolomics were performed in the pericarp of four litchi cultivars during browning. Finding results showed that a total of 119 kinds of metabolites were detected in litchi pericarp, including 30 kinds of primary metabolites, 44 kinds of volatile compounds, 29 kinds of free amino acids and 16 kinds of hydrolytic amino acids. After ANOVA and OPLS-DA, 52 kinds of metabolites were important with predictive VIP > 1 and p < 0.05. In FZX pericarp, the contents of many amino acids increased significantly, which might be related to the yellow-green pericarp and play an important role in delaying browning. In the pericarp of JGHN, NMC and HZ, a great number of soluble sugars and some free amino acids were induced during browning, which was negatively correlated with the browning speed of three red pericarp cultivars. The browning induced a large number of sesquiterpenes in the pericarp of FZX, NMC and HZ, which was positively correlated with the browning index. In addition, the correlation analysis showed that the amino acids were negatively correlated with the volatile compounds, suggesting that pericarp browning could induce the conversion of metabolic products from amino acids to terpenes. Unlabelled Image • A total of 119 metabolites were detected and identified in litchi pericarp. • A total of 52 metabolites were important with predictive VIP > 1 and p < 0.05. • Twenty free amino acids and hydrolytic amino acids was specifically induced in FZX. • Eleven soluble sugars and three free amino acids were induced in JGHN, HZ and NMC. • Browning induced 24 sesquiterpenes in the pericarp of FZX, NMC and HZ. [ABSTRACT FROM AUTHOR]

Highlights • Sodium para -aminosalicylate (PAS-Na) reduced pericarp browning of harvested litchi fruit. • PAS-Na inhibited expressions of senescence/apoptosis-related genes. • PAS-Na reduced oxidative stress in harvested litchi fruit. • PAS-Na maintained membrane integrity of litchi pericarp. • The mechanism of PAS-Na reducing browning index of harvested litchi fruit was elucidated partially. Abstract The effect of sodium para -aminosalicylate (PAS-Na) on litchi pericarp browning and the potential regulating mechanism was investigated in this study. Results showed that 0.3 g L−1 PAS-Na significantly inhibited the development of pericarp browning and reduced respiration rate of litchi fruit. PAS-Na inhibited the production of reactive oxygen species (ROS) and decreased the expression level of senescence-related genes. Additionally, PAS-Na treatment enhanced the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), which might contribute to the scavenging of ROS. Meanwhile, PAS-Na treatment maintained membrane integrity as indicated by reduced relative membrane leakage rate and malondialdehyde (MDA) content, as well as lower activities of membrane lipids-degrading enzymes: lipase and lipoxygenase (LOX). Amino acids, especially GABA, Glu, Met contents were also significantly affected by PAS-Na treatment. Taken together, we postulated that PAS-Na treatment might be a promising method for controlling postharvest browning and prolonging shelf-life of harvested litchi fruit. [ABSTRACT FROM AUTHOR]

Highlights • L. theobromae -induced disease development of longans affected energy metabolism. • L. theobromae- infection decreased ATP content and energy charge in longan pericarp. • L. theobromae- infection reduced longan pericarp Ca2+-, Mg2+- and H+-ATPase activities. • L. theobromae -induced energy deficit disrupted cell membrane structure and function. • L. theobromae -induced longan browning was related to ion disorder and energy shortage. Abstract This study aimed to investigate the effects of Lasiodiplodia theobromae (Pat.) Griff. & Maubl (L. theobromae) inoculation on the energy status and activity of adenosine triphosphatase (ATPase) during L. theobromae -induced disease development and pericarp browning of harvested 'Fuyan' longan (Dimocarpus longan Lour. cv. Fuyan) fruit. The results showed that, compared to the control longans, L. theobromae -inoculated longans displayed higher indices of fruit disease and pericarp browning, lower pericarp ATP and ADP contents, higher AMP content, lower level of energy charge, as well as lower activities of Ca2+-ATPase, Mg2+-ATPase and H+-ATPase in membranes of plasma, vacuole, and mitochondria. These results indicated that the infection of L. theobromae reduced energy status and ATPase activities, caused ions disorder, damaged the integrity and function of the cell and organelles including vacuole and mitochondria in pericarp of longan fruit, which contributed to L. theobromae -promoted disease development and pericarp browning of harvested longan fruit during storage. [ABSTRACT FROM AUTHOR]

BACKGROUND: Zinc (Zn) fertilization has been reported to improve the quality and storability of many fruits, but the mechanism had not been systematically studied. In this study, the effect of preharvest 0.2% zinc sulfate (ZnSO4) spray on the storability of longan fruits was investigated. RESULTS: The preharvest ZnSO4 spray did not significantly influence the quality but increased the Zn content in longan pericarp by 12.5‐fold. More importantly, the treatment significantly reduced the rotting rate, pericarp browning, and aril breakdown of longan fruits stored at room temperature and low temperature. Physiological and biochemical results indicated that the treatment resulted in higher water retention capacity and inhibited the degradation of cellulose, pectin, flavonoid, and phenolics of longan pericarp at the late stages of storage. Consistent with these results, the activity of cellulase, polygalacturonase, polyphenol oxidase, and lipoxygenase was significantly inhibited in the ZnSO4‐treated longan pericarp at the late stages of storage. CONCLUSION: Higher Zn content in the ZnSO4‐treated longan pericarp might help to enhance the resistance against microbial infection, inhibit the hydrolysis of cell wall components, and thus effectively protected the cell wall components, maintained the cellular compartmentation, and prevented the phenolics and flavonoid from degradation by browning‐related enzymes. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Compared to P. longanae -inoculated longan fruit, DNP-treated P. longanae -inoculated longans displayed higher fruit disease index, pericarp browning index and cell membrane permeability. Moreover, they exhibited higher activities of phospholipase D, lipase and lipoxygenase, lower amounts of phosphatidylcholine, phosphatidylinositol and USFA (unsaturated fatty acids) as well as higher amounts of phosphatidic acid and SFA (saturated fatty acids). Additionally, lower ratio of USFA to SFA and USFA index were shown in DNP-treated P. longanae -inoculated longans. However, ATP-treated P. longanae -inoculated longans exhibited the opposite results. These findings indicated that DNP stimulated longan pericarp browning and disease development caused by P. longanae resulted from the increases in activities of membrane lipids-degrading enzymes, promoting degradation of membrane phospholipids and USFA, and disruption of membrane structural integrity. Whereas, the opposite results observed in ATP-treated P. longanae -inoculated longans were due to the reduction in activities of membrane lipids-degrading enzymes and the maintenance of membrane structural integrity. [ABSTRACT FROM AUTHOR]