Browning Of Litchi Fruit Research Articles

Water Supply via Pedicel Reduces Postharvest Pericarp Browning of Litchi (Litchi chinensis) Fruit.

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.

LcVHA2 and LcVHA3 positively modulate energy metabolism and reduce pericarp browning in litchi fruit after application of Bacillus siamensis

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.

Combined Application of Malic Acid and Lycopene Maintains Content of Phenols, Antioxidant Activity, and Membrane Integrity to Delay the Pericarp Browning of Litchi Fruit During Storage.

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.

Regulation of browning and senescence of litchi fruit mediated by phenolics and energy status: A postharvest comparison on three different cultivars

Abstract Pericarp browning is one of the most important factors limiting the shelf life of litchi fruit. The storage behavior of three cultivars of litchi with different shelf life were studied to comprehensively address the importance of phenolic content and energy status in delaying the development of browning in litchi fruit after harvest. Results revealed that slower changes of browning indices; higher content of EGC, EC, ECG, GCG, PA2, total phenols and anthocyanins; lower activities of ANT, LAC, PPO, POD and PAL were detected in ‘Jingganghongnuo’, as compared to that in ‘Guiwei’ and ‘Nuomici’. The transcript abundant of oxidation-enzyme corresponding genes LcANT, LcLAC, LcPPO, LcPOD and LcPAL exhibited similar trends as changes of phenolics and enzyme activities in three cultivars. The energy status and the relative expression intensity of ATP metabolic-related genes LcATPb, LcSnRK2, LcAAC1, and LcAOX1 differed among the three cultivars and maintained higher levels in ‘Jingganghongnuo’. Accordingly, the development of pericarp browning was significantly related to the content of phenolics, especially ECG and EC, and to the changes in ATP of litchi fruit after harvest. The comparative study on variety of litchi cultivars evident that the phenolics, energy status as well as the transcript abundant of their corresponding genes are potential indicators to mark the browning change in litchi fruit.

Melatonin alleviates pericarp browning in litchi fruit by regulating membrane lipid and energy metabolisms

Melatonin functions as a pivotal bio-active molecule that is involved in diverse physiological processes in plants. This study investigated the effects of exogenous melatonin on browning, membrane phospholipids, membrane fatty acids, energy status, and activities of enzymes associated with lipid and energy metabolisms in harvested litchi (Litchi chinensis Sonn. cv. A4Wuhe) fruit during storage at 25 °C. The results exhibited that 0.4 mM melatonin treatment to litchi fruit retarded the development of browning and reduced the changes of cellular membrane permeability during storage. Melatonin treatment suppressed the increment of phospholipase D (PLD), lipase, and lipoxygenase (LOX) activities while prevented the hydrolysis of phosphatidylcholine (PC) into phosphatidic acid (PA). Compared to untreated fruit, higher contents of unsaturated fatty acids (USFA) (oleic acid, linoleic acid and linolenic acid), lower contents of saturated fatty acids (SFA) (palmitic acid and stearic acid) and a higher ratio of USFA to SFA were also found in litchi fruit receiving melatonin. In addition, melatonin treatment maintained the higher energy status, as indicated by the enhanced adenosine triphosphate (ATP) content and energy charge, which could be attributed to the enhanced activities of energy metabolism-related enzymes including H+-ATPase, Ca2+-ATPase, succinate dehydrogenase (SDH), and cytochrome C oxidase (CCO). These results suggest that melatonin could display a better performance to retard browning and senescence in litchi fruit by modulating membrane lipid and energy metabolisms.

Edible coating on litchi (Litchi chinensisSonn.) for improvement of fruit quality and shelf life: a review

Litchi (Litchi chinensis Sonn.) is one of the most important fruit crops of Sapindaceae family. As far as export of agricultural products is concerned, by virtue of its delicious taste, excellent flavour, attractive appearance and high nutritional value, it has gained popularity in many parts of the world. Litchi peels changes so quickly to brown colour within 1-2 days of harvesting. Post-harvest browning in litchi fruit is mainly associated with degradation of anthocyanin due to aerobic oxidation. However, to stay in global market, which is turning more and more competitive day by day, it is of paramount importance to maintain high standard in the qualities of fruits produced and providing longer shelf life. Many polyamines and SO2 fumigation reduces browning but leaves undesirable residue in fruit that are health hazardous and even neurotoxicity of chemicals has been reported. Keeping the seriousness in the problem and to avoid glut in the market, the present review explores the advances in technology to manage pericarp browning and to maintain overall fruit quality. Edible coating is widely applicable in fresh fruit, vegetable or their fresh-cut materials which are quite safe, environment friendly and economically acceptable. Many types of edible coatings such as polysaccharide-based coatings, cellulose and its derivatives, protein-based coatings are available to overcome losses of economic value, reduces the respiration rate as well as the physiological loss of fruit weight.

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 tea seed oil treatment on browning of litchi fruit in relation to energy status and metabolism

‘Dadingxiang’ litchi fruit were treated with 0.1% tea seed oil (TSO) and then stored at 25°C for up to 8days to investigate the effects of TSO and possible mechanisms on pericarp browning. The results showed that TSO effectively delayed the development of pericarp browning and the loss of red color in litchi fruit. TSO treatment markedly maintained membrane integrity as indicated by a lower relative electrical conductivity, which might contribute to delayed fruit senescence. In addition, TSO treatment enhanced the ATP level, energy charge and activities of H+-ATPase and Ca2+-ATPase and regulated the expression of four genes related to energy metabolism, including LcAtpB, LcAAC1, LcAOX1 and LcSnRK2. These results indicate that the process of browning and senescence in litchi fruit may be closely associated with energy status via the regulation of energy metabolism-related enzymes and genes. We suggest that TSO treatment is a convenient and safe approach for reducing browning of harvested litchi fruit.

Role of pure oxygen treatment in browning of litchi fruit after harvest

Experiments were conducted to test the effect of pure oxygen treatment on energy charge of peel tissue which may affect membrane integrity during browning of litchi fruit after harvest. Fruit were kept in air or pure O 2 for up to 6 days at 25 °C. Changes in browning index, membrane permeability, contents of ATP, ADP and AMP and energy charge were measured. As fruit browned, membrane permeability increased gradually, while ATP content and energy charge decreased rapidly. Exposure to pure O 2 significantly prevented peel browning, maintained high levels of ATP, ADP and energy charge, and reduced increase in membrane permeability of peel tissue of litchi fruit after 4 days of storage. The inhibition of browning of litchi fruit peel suggested that high levels of ATP, ADP and energy charge of litchi fruit kept in pure O 2 may contribute to maintenance of membrane integrity which reduced decompartmentation of enzymes and substrates resulting in enzymatic browning.

Biochemical and physiological changes involved in browning of litchi fruit caused by water loss

SummaryThe browning of litchi fruit pericarp caused by water loss was investigated in relation to total phenolic concentration, phenylalanine ammonia-lyase (PAL) activity, reduced glutathione content, polyphenol oxidase (PPO) and peroxidase (POD) activities, and peroxide content. Development of pericarp browning increased with reduced storage relative humidity (r.h.; from 90% to 60% r.h.) and increased storage time (from 1–3 d), and there was a strong time 2 r.h. interaction. Water loss from the pericarp increased PAL activity of pericarp of fruit stored at 60% or 70% r.h. with a maximum after 2 d storage, while activity of this enzyme stored at 80%, 90% or 95% r.h. remained at lower levels. Total phenolic compounds of litchi pericarp was initially high, and tended to decrease. Reduced glutathione content as an indicator of antioxidant capacities was lower for low storage r.h. values than for high ones, whereas a higher content of peroxides for lower storage r.h. was observed. PPO and POD activities of litchi pericarp tended to increase with reduced storage r.h. Accordingly, the results suggest that water loss-induced browning of litchi pericarp may be due to both a reduction in antioxidant capacities and an increase in oxidation of phenolics catalyzed by PPO and POD.

The control of rotting and browning of litchi fruit by hot benomyl and plastic film

Browning, weight loss and rotting of litchis ( Litchi chinensis Sonn) were studied in 3 seasons with fruit from several growing-areas in Australia. Post-harvest wastage was reduced when the fruit were dipped in hot benomyl and packed in plastic film. A benomyl dip (0.05% at 52°C for 2 min) followed by packing the fruit in punnets and over-wrapping with a “cling” pvc film (0.01 mm thickness) is suggested for controlling rotting, browning and loss in weight at temperatures of 20–30°C.