Peel Browning Research Articles

Effect of low temperature storage on energy and lipid metabolisms accompanying peel browning of ‘Nanguo’ pears during shelf life

Low temperature storage is an effective technology which is widely used in prolonging the postharvest storage of ‘Nanguo’ pears (Pyrus ussuriensis Maxim). However, the peel of pears gradually turned brown during shelf life at 20 °C after the long period of cold storage. In this study, peel browning (PB) particularly appeared during shelf life in the pears which were stored for 120 d and 180 d. Increased concentration of malondialdehyde (MDA) and electrolyte leakage were found during shelf life with the extension of refrigeration. ATP concentration and energy charge (EC) were lower in fruit stored for 180 d compared to those stored for 60 d and 120 d. Meanwhile, decreased enzymes activities and genes expression of transcripts for ATP synthase (ATPase), NADH dehydrogenase (NDA), and vacuolar proton-inorganic pyrophosphatase (VPP), which were associated with energy metabolism, were detected along with the prolonging of storage period. Moreover, the activity and gene expression of phospholipase D (PLD) were remarkably increased in fruit after long period of cold storage. The results indicated that the appearance of PB in ‘Nanguo’ pears was closely related to the extension of refrigeration, and energy deficiency and membrane damage in cells play pivotal roles on the incident of PB. The possible mechanisms are discussed.

Evaluation of biochemical markers associated with the development of husk scald and the use of diffuse reflectance NIR spectroscopy to predict husk scald in pomegranate fruit

Abstract Husk scald is a physiological rind disorder that manifests during storage and commercial shipping of pomegranate fruit. Scald affects the external quality thereby reducing its marketability, causing major economic loss to the industry worldwide. The lack of understanding of the underlying physiological and biochemical mechanisms of this disorder hinders the development of cost-effective solutions to minimise losses and assure consistent supply of quality fruit. Therefore, this study evaluated several biochemical markers associated with the development of husk scald and to discriminate between healthy and scalded fruit non-destructively. The effects of storage temperature and duration on fruit weight loss, colour attributes (L*, a*, C*, h°), browning index, total phenolics, total tannins, total anthocyanin content and enzymatic activity (polyphenol oxidase; PPO and peroxidase; POD) were investigated. The results showed that enzymatic browning was the main cause of peel browning with tannin and phenolic compounds acting as substrates for PPO and POD activity. Fruit stored at 10 °C for five months exhibited a higher incidence of scald compared to fruit at 5 °C. Fourier transform near-infrared reflectance spectroscopy was used to qualitatively discriminate between healthy and scalded fruit using orthogonal partial least squares discriminant analysis (OPLS-DA). The fruit were classified into three categories, namely, healthy, moderate scald and severe scald. A classification accuracy of 100% healthy, 92.6% moderate scald and 93% severe scald was achieved. Furthermore, the variable importance of projection (VIP) plot revealed that wavelength regions responsible for discrimination between classes were at 1350–1450, 1830–1950 and 2150–2250 nm, the wavebands attributed to stretching of C O, O H and C C bonds related to phytochemical compounds such as phenolics and anthocyanins. This study demonstrated that PPO activity, total phenolic and total tannins content were associated with the development of husk scald and these biomarkers were used to discriminate pomegranate fruit into different quality tiers.

Development of computer vision system to predict peroxidase and polyphenol oxidase enzymes to evaluate the process of banana peel browning using genetic programming modeling

Abstract The process of enzymatic browning is one of the most important chemical reactions, which effects on color, appearance and quality of fruits and vegetables. Polyphenol oxidase (PPO) and peroxidase (POD) enzymes are associated with enzymatic browning in the tissue of agricultural products. Quality of banana as a climacteric fruit is reduced by enzymatic browning during storage. Therefore, to evaluate enzymatic browning in banana, first, images of the fruits were taken at 25 °C for 9 days. Then, these images were investigated using digital image processing in order to predict and study POD and PPO enzymes during the browning process of banana peel. To this end, seventeen color parameters ( R ¯ , G ¯ , B ¯ , VR, VG; VB, r, g, b, C1, C2, C3, C4, C5, C6, C7, C8) were extracted from each image as non-destructive parameters. In the following, PPO and POD both were measured through the laboratory methods Finally, using genetic programming (GP) modeling, two equations were obtained which can be used to predict and detect the changes of the activity of the PPO and POD enzymes during the storage period (9 days). The correlation coefficients between the measured values and the predicted values for PPO and POD enzymes were 0.98 and 0.97, respectively. Furthermore, there were no significant differences between predicted values with measured values of PPO and POD enzymes (p > 0.05); these results indicate the proper performance of the designed models.

Effect of intermittent warming on alleviation of peel browning of ‘Nanguo’ pears by regulation energy and lipid metabolisms after cold storage

Refrigeration slows postharvest ripening of ‘Nanguo’ pears (Pyrus ussuriensis Maxim.), but the peel of the pears is prone to browning when the fruit are returned to room temperature. Intermittent warming (IW), in which the fruit were exposing to 20 ± 1 °C for 1 day every 20 d during storage at 0 ± 0.5 °C, retarded the occurrence of peel browning (PB) of the pears in this study. IW-treated pears showed higher firmness and ethylene production in peel of fruit during the early stage of shelf life. An increase in ATP concentration and energy charge (EC) was detected in IW-treated fruit. The concentration of malondialdehyde (MDA) and the electrolyte leakage were lower in IW-treated fruit. Higher enzyme activity and increased gene expression of transcripts for ATP synthase (ATPase), NADH dehydrogenase (NDA) and vacuolar proton-inorganic pyrophosphatase (VPP), which were associated with oxidative phosphorylation, were found in IW-treated fruit during the shelf life. Lower enzyme activity and down-regulated gene expression levels of phospholipase D (PLD) involved in glycerophospholipid metabolism were found in fruit under IW treatment. These results indicate that the PB of ‘Nanguo’ pears can be effectively alleviated by IW treatment and the possible mechanisms are discussed.

Minimize browning incidence of banana by postharvest active chitosan/PVA Combines with oxalic acid treatment to during shelf-life

Abstract The effect of anti-browning by exogenous of chitosan/polyvinyl alcohol (CS/PVA) blended with oxalic acid (OA) at different concentration (0, 10, 15 and 20 mM) on ‘Williams’ banana coating to minimize fruit peel browning during shelf life/marketing. Fruits were immersed in different CS/PVA-OA treatments for 10 min and stored at room temperature (24 ± 1 and RH 58 ± 2). Samples were taken every two days for non-destructive and destructive measurements. CS/PVA-OA 20mM presents a significant reduction in cell membrane degrading enzyme activities such as cellulase (CEL), lipoxygenase (LOX) and pectinase (PT). Consequently, it minimizes lipid peroxidation and cell membrane leakage. Then browning enzymes activities polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) minimized by maintaining total phenols and less browning incidence on fruit peel during shelf life. Overall, oxalic acid could minimize the browning enzyme activities to ensure a smooth surface and long term of the shelf life of banana at room temperature.

Regulatory effects of CaCl2, sodium isoascorbate, and 1‐methylcyclopropene on chilling injury of banana fruit at two ripening stages and the mechanisms involved

To improve fruit chilling tolerance during postharvest storage, banana fruit at two ripening stages (green and yellow) were pretreated with 2% (wt/vol) CaCl2 (Ca2+) or 1% (wt/vol) sodium isoascorbate (SI) under vacuum infiltration, or fumigated with 1.0 μL/L 1-methylcyclopropene (1-MCP), then stored at 6 °C. Application of Ca2+ or SI significantly reduced chilling injury index, electrolyte leakage, malondialdehyde content, and polyphenol oxidase activity of banana peel during storage at 6 °C. And Ca2+ or SI also sustained levels of firmness, peel lightness, and promoted activities of peroxidase, superoxide dismutase, catalase, and ascorbate peroxidase in banana at two ripening stages. Application of 1-MCP resulted in positive effects only on the visual quality of yellow ripening banana. Our results indicated that Ca2+ or SI could ameliorate chilling injury of both mature green and yellow ripening banana fruit stored at 6 °C; 1-MCP could enhance chilling tolerance of yellow ripening banana. Practical applications Refrigeration is a usual method for extending storage life of banana fruit. Like other tropical and subtropical fruits, banana is highly susceptible to chilling injury (CI) and develops CI symptoms of rapid peel browning, pulp rigidity, and pitting when stored at low temperature. Our results indicate that 2% (wt/vol) calcium chloride or 1% (wt/vol) sodium isoascorbate are effective methods in alleviating CI of the banana at two ripening stages. A total of 1.0 μL/L 1-methylcyclopropene significantly reduced CI of yellow ripening banana, while exacerbation of CI was observed in green maturity banana during the storage. This research not only provides environmentally friendly chemicals for postharvest application but also investigates the effects of chemical treatments on CI both of mature green banana and yellow ripening banana.

Effects of low temperature conditioning on fruit quality and peel browning spot in ‘Huangguan’ pears during cold storage

‘Huangguan’ pears are susceptible to peel browning spots (PBS) during cold storage. In this study, the effects of low temperature conditioning (LTC) on fruit firmness, soluble solids content (SSC) and PBS incidence in ‘Huangguan’ pears were investigated. Fruit were directly stored at 0°C (control) and conditioned at 10°C for 3 d (LTC), respectively. Afterwards, all fruit were stored at 0°C. Fruit firmness was unaffected by the LTC treatment. However, SSC was higher in the LTC-treated fruit than in control fruit on days 30 and 60. Compared with the control, LTC treatment effectively inhibited the development of PBS, reduced the activities of lipoxygenase (LOX) and polyphenol oxidase (PPO), reduced malondialdehyde (MDA) content in peel tissue, the decline in the phenolic content, and it showed higher proline content before the appearance of PBS. In addition, LTC treatment decreased the expression levels of LOX1, PPO1 and PPO5 genes, while it up-regulated the expression of the PPO4 gene in peel tissue. These results indicate that the alleviation effect of LTC on the development of PBS was closely related to reduced membrane lipid peroxidation, activities of LOX and PPO, and the expression of LOX1, PPO1 and PPO5 genes in peel tissue in ‘Huangguan’ pears.

Low temperature conditioning alleviates peel browning by modulating energy and lipid metabolisms of ‘Nanguo’ pears during shelf life after cold storage

Refrigeration is a common technique for impeding the postharvest ripening of the ‘Nanguo’ pear (Pyrus ussuriensis Maxim.). However, peel of pears gradually become brown when the fruit are returned to room temperature after cold storage. Low temperature conditioning (LTC), in which fruit were initially stored at 10°C and then cooled during a 20 day period, delayed the incidence of peel browning (PB) of pears in our study. LTC-treated fruit showed a decrease in the content of malondialdehyde (MDA) and the relative leakage rate of the peel. The ATP content and energy charge (EC) were higher in LTC-treated pears. Gene expression levels of transcripts for NADH dehydrogenase (NDA), ATP synthase (ATPase) and vacuolar proton-inorganic pyrophosphatase (VPP), which were involved in oxidative phosphorylation, were all up-regulated by LTC treatment. Gene expression levels of phospholipase D (PLD) involved in glycerophospholipid metabolism were lower in LTC-treated fruit during the shelf-life. These results indicate that LTC treatment can effectively alleviate the PB of ‘Nanguo’ pear and the possible mechanisms are discussed.

Application of Exogenous Ethylene Inhibits Postharvest Peel Browning of ‘Huangguan’ Pear

Peel browning disorder has an enormous impact on the exterior quality of ‘Huangguan’ pear whereas the underlying mechanism is still unclear. Although different methods have been applied for inhibiting the peel browning of ‘Huangguan’ pear, there are numerous issues associated with these approaches, such as time cost, efficacy, safety and stability. In this study, to develop a rapid, efficient and safe way to protect ‘Huangguan’ pear from skin browning, the effect of exogenous ethylene on peel browning of pear fruits stored at 0°C was evaluated. Results showed that ethylene treatments at 0.70–1.28 μL/L significantly decreased the browning rate and browning index from 73.80% and 0.30 to 6.80% and 0.02 after 20 days storage at 0°C, respectively, whereas ethylene treatments at 5 μL/L completely inhibited the occurrence of browning. In addition, ethylene treatments at 5 μL/L decreased the electrolyte leakage and respiration rate, delayed the loss of total phenolic compounds. Furthermore, ethylene (5 μL/L) treatment significantly enhanced the activity of catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) and increased the 1, 1-diphenyl-2-picrylhydrazyl inhibition rate, but inhibited the activity of polyphenol oxidase (PPO) and peroxidase (POD). Our data revealed that ethylene prevented the peel browning through improving antioxidant enzymes (CAT, APX and SOD) activities and reducing PPO activity, electrolyte leakage rate and respiration rate. This study demonstrates that exogenous ethylene application may provide a safe and effective alternative method for controlling browning, and contributes to the understanding of peel browning of ‘Huangguan’ pear.

The Effect of Controlled-release Chlorine Dioxide on the Preservation of Grapefruit

The effect of controlled-release chlorine dioxide (ClO2) gas on the safety and quality of grapefruit was studied. The experiments were run under controlled chamber systems with inoculated fruit, and in boxed fruit under commercial conditions. For the inoculation test, fruit artificially inoculated with either Escherichia coli or Penicillium digitatum, or naturally inoculated Xanthomonas citri ssp. citri (Xcc) (fruits with citrus canker lesions), were incubated in a chamber containing a dose equivalent to 0–60 mg·L−1 of pure ClO2 as an antimicrobial agent. After 24 hours, the microbial population on treated grapefruit was significantly reduced compared with that of control fruit: a dosage of 5 mg·L−1 completely inhibit the growth of E. coli and P. digitatum, but a dosage of 60 mg·L−1 was needed to completely kill Xcc. For the simulated commercial experiment, fruit were harvested in late Oct. 2015 passed through a commercial packing line, and packed in 29 L citrus boxes. ClO2 packets were attached to the top lids with the following five treatments: fast-release, slow-release, slow/fast-release combination (each containing 14.5 mg·L−1 of pure ClO2), double dose fast-release (containing 29 mg·L−1 of ClO2), and control. After 6 weeks of storage at 10 °C (to simulate storage and transportation) + 1 week of storage at 20 °C (to simulate retail marketing), the fruit quality was evaluated. The slow-release treatment at standard dose exhibited the best antimicrobial activity, reducing total aerobic bacterial count and yeast/mold count by 0.95 and 0.94 log colony-forming units (cfu)/g of fruit, respectively, and maintained the best visual, sensory, and overall quality. However, the higher dosage treatments resulted in phytotoxicity as evidenced by peel browning.

Proteomic analysis of peel browning of 'Nanguo' pears after low-temperature storage.

Postharvest ripening of the 'Nanguo' pear (Pyrus ussuriensis Maxim.) can be impeded by low-temperature storage. However, pears after long-term refrigeration are prone to peel browning when returned to room temperature conditions. This study investigated the browning mechanism of 'Nanguo' pear stored at a low temperature by analysing the differentially expressed proteins between healthy fruit and fruit with peel browning. The results showed that 181 proteins underwent statistically significant changes. A categorisation of the disparately accumulated proteins was performed using gene ontology annotation. The results showed that the 'metabolic process', 'cellular process', 'catalytic activity', and 'binding' proteins were the most affected after low-temperature storage. Further analysis revealed that the differentially expressed proteins, which are related to peel browning, are primarily involved in the phenylpropanoid pathway, linoleic acid pathways, fatty acid biosynthesis pathway, glutathione metabolism pathway, photosynthesis pathway, oxidative phosphorylation pathway, and glycolysis pathway. This study reveals that there are variations in key proteins in 'Nanguo' pear after low-temperature storage, and the identification of these proteins will be valuable in future functional genomics studies, as well as provide protein resources that can be used in the efforts to improve pear quality. © 2016 Society of Chemical Industry.

Extraction conditions of polyphenol oxidase from banana peel

Polyphenol oxidase (PPO) is an enzyme containing copper, presents in various fruits and vegetables. It is responsible for the browning reactions when the cells are damaged during handling. The best conditions for extraction of polyphenol oxidase from banana peel was by using an extraction buffer containing phosphate buffer (0.05 M, pH 7), 0.01 M ascorbic acid and 0.5% polyethylene glycol, with extraction ratio 1:4 (w:v) for one minute by using blender. The enzyme activity was measured spectrophotometrically at 425 nm. PPO was studied to prevent the browning of banana peel which results in the loss of their marketability. The aim of this study was to determine the optimum conditions for polyphenol oxidase extraction from banana peel.

Influence of Exogenous Spermidine on to Peel Color Change and Browning Symptom of Musa (AAA group) cv. Kluai Hom Thong at Low Temperature Storage

Musa (AAA Group) cv. Kluai Hom Thong is popular and widely consumed fruits in Thailand and overseas. This experiment showed an influence of spermidine (SPD) on change of peel color and browning in banana. Ripe bananas were soaked with 0, 0.2, 0.5 and 2.0 mM and then stored at 10 oC, 85±5 %RH. Bananas, treated with 0.5 and 2.0 mM SPD, showed alteration of biochemical changes such as color, ripping and enzymatic browning reaction. Biochemical changes included chlorophyll, carotenoid, phenolic compounds, as well as polyphenol oxidase and peroxidase activities which increased during storage. Bananas, treated with SPD at 0.5 and 2.0 mM, exhibited a reduction in an accumulation of phenolic compounds, polyphenol oxidase and peroxidase activities, comparing with the non-treated SPD samples.

Extraction conditions of polyphenol oxidase from banana peel

Polyphenol oxidase (PPO) is an enzyme containing copper, presents in various fruits and vegetables. It is responsible for the browning reactions when the cells are damaged during handling. The best conditions for extraction of polyphenol oxidase from banana peel was by using an extraction buffer containing phosphate buffer (0.05 M, pH 7), 0.01 M ascorbic acid and 0.5% polyethylene glycol, with extraction ratio 1:4 (w:v) for one minute by using blender. The enzyme activity was measured spectrophotometrically at 425 nm. PPO was studied to prevent the browning of banana peel which results in the loss of their marketability. The aim of this study was to determine the optimum conditions for polyphenol oxidase extraction from banana peel.

Control of litchi downy blight by zeamines produced by Dickeya zeae.

Zeamines (ZMS), a class of polyamine-polyketide-nonribosomal peptide produced by bacterial isolate Dickeya zeae, were shown recently to be potent antibiotics against some bacterial pathogens. In this study, the results indicated that ZMS showed antifungal activity against Peronophythora litchii and other fungal pathogens. The activity of ZMS against the oomycete pathogen P. litchi, which causes the devastating litchi downy blight, was further investigated under in vitro and in vivo conditions. ZMS displayed potent inhibitory activity against the mycelial growth and sporangia germination of P. litchii. At a concentration of 2 μg/mL, about 99% of the sporangia germination was inhibited. Scanning electron microscopy and transmission electron microscopy analyses showed that treatment with ZMS could cause substantial damages to the oomycete endomembrane system. Furthermore, treatment of litchi fruits with ZMS solution significantly (P < 0.05) reduced the fruits decay and peel browning caused by P. litchii infection during storage at 28 °C. Taken together, our results provide useful clues on the antifungal mechanisms of ZMS, and highlight the promising potentials of ZMS as a fungicide, which in particular, may be useful for prevention and control of litchi fruits decay and browning caused by P. litchii infection during storage and transportation.

Image analysis to evaluate the browning degree of banana (Musa spp.) peel

Image analysis was applied to examine banana peel browning. The banana samples were divided into 3 treatment groups: no treatment and normal packaging (Cont); CO2 gas exchange packaging (CO); normal packaging with an ethylene generator (ET). We confirmed that the browning of banana peels developed more quickly in the CO group than the other groups based on sensory test and enzyme assay. The G (green) and CIE L∗, a∗, and b∗ values obtained from the image analysis sharply increased or decreased in the CO group. And these colour values showed high correlation coefficients (>0.9) with the sensory test results. CIE L∗a∗b∗ values using a colorimeter also showed high correlation coefficients but comparatively lower than those of image analysis. Based on this analysis, browning of the banana occurred more quickly for CO2 gas exchange packaging, and image analysis can be used to evaluate the browning of banana peels.

Inhibición del bronceado en cáscara de chirimoya ‘Fino de Jete’ por aplicación de 6-bencilaminopurina

The cherimoya (Annona cherimola Mill.) fruit is climacteric and has a very short postharvest life; the symptoms of senescence include peel browning and fruit softening. The objective of this research was to evaluate the effect of application of 6-benzylaminopurine (BAP) in the postharvest life of cherimoya fruit ‘Fino de Jete’. Fruits were randomly selected from the middle and basal part of six trees. BAP was applied at 1.0 mM or 0 mM in every of two dates, that is 8 or 15 days before harvest (DAC). After harvest, fruits were transported for 1.5 h and stored in two different temperatures, refrigerated (TR) (6 °C) or room temperature (TA) (16 ± 2 °C). Every third day, from 1 to 15 day after harvest (DDC), they were analyzed in relation to weight loss, color L*, a* and b*, and fruit firmness and deformation. In TA, the fruits treated with 1 mM BAP in both, 8 or 15 DAC retained peel color L* over 35% (ρ ≤ 0.05) in relation to control.

Postharvest Low Temperature Conditioning Reduces Peel Browning and Improves Fruit Quality in Storage and Subsequent Shelf Life of Huangguan Pear

Huangguan pear (Pyrus bretschneideri Rehd cv. Huangguan) is a pear cultivar that rapidly developed in China. However, rapid postharvest browning appearing in fruit peel and core during storage and shelf life pose a challenge for their marketing. The potential for low temperature conditioning (LTC) treatment to inhibit peel browning and improve quality of Huangguan pears in storage and shelf life was investigated. Pears were treated at 8℃ - 9℃ for 1, 3, 6 and 9 d, respectively, physiological indexes, including peel and core browning, core breakdown, malondialdehyde (MDA) content and ethanol content were determined and quality in storage period and shelf life was evaluated in this paper. LTC treatment alleviated peel browning and core browning either in storage or shelf life remarkably; it also delayed the decline of firmness, total soluble solids and titratable acidity in storage to some extent, inhibited ethanol and MDA content both in storage and shelf life effectively and maintained juiciness and crispness of pear fruit in shelf life. These results showed that LTC can serve as an important tool for the regulation of Huangguan pears external and internal quality in storage and shelf life with economic benefits and LTC treatment for 6 d was the optimum condition in the present study.

Antifungal Activity of Hypothemycin against Peronophythora Litchii In Vitro And In Vivo

The antifungal activity of a natural resorcylic acid lactone, hypothemycin (HPM), against Peronophythora litchii in vitro and in vivo was investigated. HPM treatment substantially suppressed spore germination of P. litchi, with the inhibition rate of 100% when 0.78 μg/mL HPM was applied. Similarly, mycelial growth of P. litchii was efficiently inhibited. Furthermore, HPM caused the ultrastructural modifications of P. litchii, including the disruption of the cell wall and the endomembrane system, especially the plasma membrane, mitochondria, and vacuoles, which led to the destruction of the cellular integrity. Moreover, application of HPM significantly reduced decay and suppressed peel browning of postharvest litchi fruit inoculated with P. litchii during storage at 28 °C. Overall, these findings suggested that HPM exhibited excellent antifungal activity against P. litchii both in vitro and in vivo, which could be helpful for the storage of harvest litchi fruit.

Chilling injury in mango (Mangifera indica) fruit peel: Relationship with ascorbic acid concentrations and antioxidant enzyme activities

We investigated the degree of chilling injury (CI) in mango (Mangifera indica) fruit stored at 4°C or 12°C, in relation to peel ascorbic acid concentrations, total antioxidant capacity, and the activities of four antioxidative enzymes. In cv. Nam Dok Mai fruit exposed to 4°C, CI (peel browning) was found after 5 days, whilst CI in cv. Choke Anan fruit started after 10 days and did not reach the same degree. When held at 27–28°C, following various periods of exposure to 4°C, peel browning in both cultivars increased, but that in cv. Nam Dok Mai remained higher than in cv. Choke Anan. An inverse correlation was found between peel browning and ascorbic acid concentrations, and between peel browning and total antioxidant capacity, measured using the FRAP method. In cv. Nam Dok Mai, the superoxide dismutase (SOD) and catalase (CAT) activities were lower during storage at 4°C than during storage at 12°C, while such a difference was not found in cv. Choke Anan. When compared to cv. Choke Anan, lower activities of ascorbate peroxidase (APX) and of guaiacol peroxidase (POX) were found in the peel of cv. Nam Dok Mai. However, no difference was observed in APX and in POX activities in the peel of cv. Nam Dok Mai stored at 4°C or 12°C. This means that the relationships between CI and APX and POX activities were weak.