Pericarp Browning Of Litchi Fruit Research Articles

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.

Laccase-Mediated Flavonoid Polymerization Leads to the Pericarp Browning of Litchi Fruit.

Litchi pericarp turns brown rapidly after fruit harvest, while the mechanism remains obscure. The contents of (-)-epicatechin (EC) and procyanidins (PCs) A2/B1/B2/C1 decreased during the pericarp browning, and a previously identified laccase (ADE/LAC) showed activity to these compounds, with brown products observed in the reactions. By UPLC-DAD-QTOF-MS/MS, isomers of dimeric, trimeric, and tetrameric PCs were detected in the EC-ADE/LAC reaction. In the presence of cyanidin-3-O-rutiside and rutin, anthocyanin-EC and rutin-EC adducts were, respectively, produced, and darker brown precipitation was observed in these reactions relatively to the EC-ADE/LAC reaction alone. ADE/LAC catalyzed the conversion of PC B2 to A-type PC dimers and B-type PC tetramers. ADE/LAC complemented the transparent testa of Arabidopsis LAC15-loss-of-function mutant (tt10) to wild-type dark brown seed coat. The results demonstrated that ADE/LAC-mediated flavonoid polymerization played an important role in the browning of pericarp.

α-Lipoic acid treatment alleviates postharvest pericarp browning of litchi fruit by regulating antioxidant ability and energy metabolism

Litchi fruit has high commercial value and significant benefits for humans. However, pericarp browning, as the indicator of litchi fruit senescence, limits the shelf life of litchi fruit. Effect of α-lipoic acid (α-LA) that has great antioxidant potential, on litchi fruit senescence was investigated. Results showed that α-LA delayed pericarp browning and attenuated redox stress of litchi fruit, indicated by lower hydrogen peroxide (H2O2) and superoxide radical (O2−·) contents but higher hydroxy radical scavenging rate. Compared to control, α-LA treatment enhanced enzymatic: superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) as well as nonenzymatic antioxidants: glutathione (GSH) and ascorbate (AsA). Meanwhile, α-LA was protective against oxidative stress by inducing glutaredoxin (LcGrx), thioredoxin (LcTrx) and methionine sulfoxide reductase (LcMsr) expression levels. These α-LA-induced antioxidant systems directly increased the antioxidant capacity. Further research indicated that α-LA pretreatment maintained higher intracellular ATP level and activated extracellular ATP signaling through up-regulating LcDORN1s expression, indirectly increasing the antioxidant capacity. In conclusion, α-LA is effective to increase the antioxidant capacity and delay the pericarp browning of litchi fruit.

Choline chloride alleviates the pericarp browning of harvested litchi fruit by inhibiting energy deficiency mediated programmed cell death

Abstract The effect of choline chloride (ChCl) on litchi pericarp browning and the potential regulating mechanism was investigated in this study. Results showed that 1 g L−1 ChCl significantly inhibited the development of pericarp browning and reduced respiration rate of litchi fruit. Meanwhile, choline chloride treatment delayed the programmed cell death (PCD) indicated by lower DNA laddering, inhibition of programmed cell death-related genes expression and higher soluble protein content. Additionally, ChCl treatment maintained higher ATP content and energy charge due to higher level of glycine betaine and regulation of energy metabolism related genes and ATPase activities by ChCl treatment. Finally, higher ATP status in ChCl treated fruit resulted in lower accumulation of reactive oxygen species via enhancing the activities of superoxide dismutase, catalase and ascorbate peroxidase. Taken together, the results obtained in this study suggested that choline chloride reduced pericarp browning of litchi fruit possibly through inhibiting energy deficiency mediated PCD.

Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature

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. Keywords: litchi, pericarp browning, dry fog, high relative humidity, cold storage DOI: 10.25165/j.ijabe.20191204.4420 Citation: Xiao L, Li T T, Jiang G X, John A, Zhang D D, Jin W Y, et al. Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature. Int J Agric & Biol Eng, 2019; 12(4): 192–196.

Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature

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. Keywords: litchi, pericarp browning, dry fog, high relative humidity, cold storage DOI: 10.25165/j.ijabe.20191204.4420 Citation: Xiao L, Li T T, Jiang G X, John A, Zhang D D, Jin W Y, et al. Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature. Int J Agric & Biol Eng, 2019; 12(4): 192–196.

Exogenous Application of Oxalic Acid Delays Pericarp Browning and Maintain Fruit Quality of Litchi cv. “Gola”

The present study was conducted to investigate the influence of oxalic acid on pericarp browning, biochemical quality, antioxidative and enzymatic changes in litchi cv. “Gola” fruit under extended cold storage, which has not been studied extensively. Postharvest application of 2 mM oxalic acid reduced fruit weight loss and delayed pericarp browning by maintaining higher anthocyanin contents, as compared with control. Activities of polyphenol oxidase and peroxidase enzymes in litchi peel as well as pulp tissues were reduced in fruit treated with 2 mM oxalic acid during 28 days of cold storage. Activities of antioxidative enzymes (superoxide dismutase and catalase) and level of total phenolic contents and total antioxidants in litchi peel as well as pulp tissues were significantly higher in 2 mM oxalic acid-treated fruit. In conclusion, postharvest application of 2 mM oxalic acid significantly delayed pericarp browning and maintained better quality of litchi cv. “Gola” fruit during cold storage. Practical Applications Pericarp browning of litchi fruit is associated with postharvest oxidative stress, which deteriorates its quality, long-term storability and commercial value. Postharvest application of oxalic acid has been found to be a useful strategy to overcome the issue of pericarp browning and enhance antioxidative potential of litchi under low temperature storage; thereby, applicable to commercial supply chains for domestic and export markets. Furthermore, this study may facilitate in understanding the changes in antioxidative potential and enzymatic activities during cold storage with gradual browning in pulp as well as peel tissues of litchi.

Effect of tea polyphenols on lipid peroxidation and antioxidant activity of litchi (Litchi chinensis Sonn.) fruit during cold storage.

To understand the potential of application of tea polyphenols to the shelf life extension and quality maintenance of litchi (Litchi chinensis Sonn.) fruit, the fruits were dipped into a solution of 1% tea phenols for 5 min before cold storage at 4 °C. Changes in browning index, contents of anthocyanins and phenolic compounds, superoxide dismutase (SOD) and peroxidase (POD) activities, O2.− production rate and H2O2 content, levels of relative leakage rate and lipid peroxidation, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were measured after 0, 10, 20 and 30 days of cold storage. The results showed that application of tea polyphenols markedly delayed pericarp browning, alleviated the decreases in contents of total soluble solids (TSS) and ascorbic acid, and maintained relatively high levels of total phenolics and anthocyanins of litchi fruit after 30 days of cold storage. Meanwhile, the treatment reduced the increases in relative leakage rate and lipid peroxidation content, delayed the increases in both O2.− production rate and H2O2 contents, and increased SOD activity but reduced POD activity throughout this storage period. These data indicated that the delayed pericarp browning of litchi fruit by the treatment with tea polyphenols could be due to enhanced antioxidant capability, reduced accumulations of reactive oxygen species and lipid peroxidation, and improved membrane integrity.

Cloning and expression analysis of litchi (Litchi Chinensis Sonn.) polyphenol oxidase gene and relationship with postharvest pericarp browning.

Polyphenol oxidase (PPO) plays a key role in the postharvest pericarp browning of litchi fruit, but its underlying mechanism remains unclear. In this study, we cloned the litchi PPO gene (LcPPO, JF926153), and described its expression patterns. The LcPPO cDNA sequence was 2120 bps in length with an open reading frame (ORF) of 1800 bps. The ORF encoded a polypeptide with 599 amino acid residues, sharing high similarities with other plant PPO. The DNA sequence of the ORF contained a 215-bp intron. After carrying out quantitative RT-PCR, we proved that the LcPPO expression was tissue-specific, exhibiting the highest level in the flower and leaf. In the pericarp of newly-harvested litchi fruits, the LcPPO expression level was relatively high compared with developing fruits. Regardless of the litchi cultivar and treatment conditions, the LcPPO expression level and the PPO activity in pericarp of postharvest fruits exhibited the similar variations. When the fruits were stored at room temperature without packaging, all the pericarp browning index, PPO activity and the LcPPO expression level of litchi pericarps were reaching the highest in Nandaowuhe (the most rapid browning cultivar), but the lowest in Ziniangxi (the slowest browning cultivar) within 2 d postharvest. Preserving the fruits of Feizixiao in 0.2-μm plastic bag at room temperature would decrease the rate of pericarp water loss, delay the pericarp browning, and also cause the reduction of the pericarp PPO activity and LcPPO expression level within 3 d postharvest. In addition, postharvest storage of Feizixiao fruit stored at 4°C delayed the pericarp browning while decreasing the pericarp PPO activity and LcPPO expression level within 2 d after harvest. Thus, we concluded that the up-regulation of LcPPO expression in pericarp at early stage of postharvest storage likely enhanced the PPO activity and further accelerated the postharvest pericarp browning of litchi fruit.

EFFECTS OF ULTRASONIC TREATMENT ON PERICARP BROWNING OF POSTHARVEST LITCHI FRUIT

ABSTRACT Pericarp browning and decline in quality are the major postharvest problems of litchi fruit (Litchi chinensis Sonn.) during storage and transportation. Experiments were conducted to investigate the effects of ultrasonic treatment on pericarp browning and quality of harvested litchi fruit. Fresh fruits of litchi cv. Guiwei were treated with ultrasonic at power of 0 (control) or 120 W for 10 min in water and then stored at room temperature (28C). Application of ultrasonic generally reduced the degradation of litchi anthocyanins and increase in relative leakage rate throughout the storage period, and inhibited the activities of polyphenol oxidase and peroxidase at the early storage stage and, thus, significantly delayed pericarp browning of litchi fruit. However, ultrasonic treatment accelerated the reduction in the amount of total soluble solids and slowed down the increase in total titratable acid. All these results suggest that the application of ultrasonic can effectively control the pericarp browning of postharvest litchi fruit during storage. PRACTICAL APPLICATIONS Litchi fruit has a very short storage life under ambient conditions because of the browning and quality deterioration. Various approaches are now applied to extend the storage life of litchi fruit, such as sulfur fumigation, chitosan coating and acidic treatment. Although sulfur treatment has been adopted widely, sulfur residue remains to be solved. Therefore, a novel postharvest technique ultrasonic sound without hazard to human health is needed urgently. In this study, ultrasonic treatment was used to effectively delay the pericarp browning of harvested litchi fruit. This prospective technique will be helpful to solve the problem of litchi browning from another angle and substitute the chemical approaches of antibrowning to prolong the storage life and control the decay of litchi.

INHIBITORY EFFECT OF ANTHOCYANIN EXTRACT FROM SEED COAT OF BLACK BEAN ON PERICARP BROWNING AND LIPID PEROXIDATION OF LITCHI FRUIT DURING STORAGE

ABSTRACT Anthocyanins were extracted from seed coats of black beans (Glycine max[L.]) and the inhibitory effects of anthocyanin extract on pericarp browning and lipid peroxidation of litchi fruit were investigated. Litchi fruit were infiltrated for 3 min with 0 (control) or 50 mg/L of anthocyanin extract at a reduced pressure of 53 kPa, then packed in 0.03 mm thick polyethylene bags, and finally stored at 28C for 6 days. Changes in browning index, contents of anthocyanins and total phenol, peroxidase (POD) activity, levels of relative leakage rate and lipid peroxidation, α,α-diphenyl-β-picrylhydrazy (DPPH) radical scavenging activity and reducing power were evaluated. Application of anthocyanin extract from black bean delayed pericarp browning of litchi fruit during storage, which was associated with reduced POD activity and higher contents of anthocyanins and total phenol. Moreover, the anthocyanin extract was found to have a direct inhibition on the POD activity in vitro. Furthermore, application of the anthocyanin extract apparently reduced lipid peroxidation and relatively maintained membrane integrity, which may account for browning inhibition to an extent. Finally, higher DPPH radical scavenging activity and reducing power of the fruits treated with the anthocyanin extract than control fruits possibly benefited in scavenging free radicals and reducing lipid peroxidation. It is, therefore, suggested that inhibited POD activity and reduced lipid peroxidation by the anthocyanin extract from seed coats of black beans were responsible for the inhibition of pericarp browning of litchi fruits. PRACTICAL APPLICATIONS Lipid peroxidation is a major cause of quality deterioration of postharvest fruits and vegetables. Some synthetic antioxidants are beneficial in inhibiting lipid peroxidation. However, considering that synthetic antioxidants, such as butylhydroxyanisole and butylated hydroxytoluene (BHT), have potential toxicity, the use of natural extracts to extend the shelf life of postharvest fruits and vegetables is a tendency. In our previous study, it has been found that anthocyanin extract from litchi pericarp has stronger antioxidant activities or free radical scavenging activities than BHT and ascorbic acid (Duan et al. 2007). In this study, the application of anthocyanin extract from seed coat of black soybean showed reduced lipid peroxidation and pericarp browning. It could be used potentially as a postharvest technology for reducing or replacing the use of other chemicals, but it requires further investigation.

Evaluation of the Antioxidant Properties of Litchi Fruit Phenolics in Relation to Pericarp Browning Prevention

Phenolics were extracted from litchi fruit pericarp (LFP) tissues, purified and their antioxidant properties analyzed. LFP phenolics strongly inhibited linoleic acid oxidation and exhibited a dose-dependent free-radical scavenging activity against alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH*) and hydroxyl radicals and superoxide anions. The degradation of deoxyribose by hydroxyl radicals was inhibited by phenolics acting mainly as iron ion chelators, rather than by directly scavenging the radicals. Phenolics from litchi fruit pericarp were found to display similar reducing power activity as ascorbic acid. The effect of phenolic compound treatment on pericarp browning and electrolyte leakage of litchi fruit was also evaluated and it was observed that application of exogenous litchi phenolics to harvested litchi fruit significantly prevented pericarp browning and delayed increases in electrolyte leakage. These results suggest that litchi pericarp tissue phenolics could be beneficial in scavenging free radicals, maintaining membrane integrity and, thereby inhibiting pericarp browning of litchi fruit.

Postharvest control of pericarp browning of litchi fruit ( Litchi chinensis Sonn cv Kwaï Mi) by treatment with chitosan and organic acids : I. Effect of pH and pericarp dehydration

Postharvest pericarp browning of litchi fruit ( Litchi chinensis Sonn cv Kwaï Mi) significantly reduces its commercial potential on the fresh market. In this study, a new treatment, based on the use of organic acids (citric or tartaric) in association with chitosan coating, both harmless for human health, has been tested. Trials at pH 0.8, 1.0 and 1.3 show that browning rate is related to dehydration rate during storage, and pericarp pH. Pericarp pH and weight loss of fruit may thus be used to predict postharvest browning rate at a given storage temperature.

Effect of oxalic acid on control of postharvest browning of litchi fruit

Litchi ( Litchi chinensis Sonn.) fruit, cv. Huaizhi, was treated with 2 and 4 mM oxalic acid and stored at room temperature to investigate the effect of oxalic acid on pericarp browning. The results showed that the pericarp browning indices of the fruit, treated with both oxalic acid concentrations, were significantly lower than that of the control, due to increase of membrane integrity, inhibition of anthocyanin degradation, decline of oxidation, and maintanance of relatively low peroxidase activity in the fruit during storage. It appears that application of oxalic acid can effectively control the pericarp browning of litchi fruit during postharvest storage.

Effects of chitosan coating on shelf life of cold-stored litchi fruit at ambient temperature

Postharvest pericarp browning of litchi fruit results in an accelerated loss in shelf life and a reduced commercial value. Visual quality was lost in only 6 h at ambient temperature when fruit were removed from storage at 2 °C, due to browning. The experiment was conducted to test the role of chitosan coating in inhibiting skin browning and extending shelf life of cold-stored litchi fruit at ambient temperature. Litchi fruit were treated with 2 g chitosan/100 g solution and then stored for 20 days at 2 °C and 90–95% relative humidity (RH), prior to shelf life evaluation at 25 °C and 80–90% RH. Changes in polyphenol oxidase (PPO) activity, anthocyanin concentration, colour index, eating quality and concentrations of total soluble solids and titratable acidity were measured. The effects of chitosan coating on disease incidence were also evaluated. Application of chitosan coating delayed the decrease in anthocyanin content, the increase in PPO activity and the changes in colour index and eating quality, reduced the decrease in concentrations of total soluble solids and titratable acidity, and partially inhibited decay. The results suggested that treatment with chitosan coating exhibited a potential for shelf life extension at ambient temperature when litchi fruit were removed from cold storage.

Effects of low-temperature acclimation on browning of litchi fruit in relation to shelf life

SummaryPostharvest pericarp browning of litchi fruit results in an accelerated loss in shelf life and reduced commercial value. Visual quality was lost in only 6.h at room temperature after fruit were removed from storage at 2°C, due to browning. Cultivar ‘Huaizhi’ fruit stored for 2 d at 8°C, for 26 d at 2°C, followed by 2 d storage at 15°C prior to a shelf-life evaluation at 23–258C, 80–90% r.h. were compared with continuous storage for 30 d at 2°C. Changes in polyphenol oxidase (PPO), anthocyanin, membrane leakage, colour, eating quality, total soluble solids, titratable acidity, and ascorbic acid were measured. The effects of temperature conditioning on disease incidence was also evaluated. Application of low-temperature acclimation delayed the decrease in anthocyanin content, the increases in PPO activity and membrane leakage, the changes in colour and eating quality, and partially inhibited decay of fruit. The results suggested that potential exists for shelf-life extension at ambient temperature when fruit are acclimated.