Cold-stored Fruit Research Articles

Design and implementation of temperature and humidity monitoring system for small cold storage of fruit and vegetable based on Arduino

At present, the utilization rate of small cold storage for fruit and vegetable in Yunnan is low, and it is necessary to carry out regional management of cold storage in order to save energy and improve the utilization rate. Because different fruits and vegetables need different refrigeration temperatures, so real-time temperature and humidity monitoring is particularly important. For meeting this requirement, this paper designs an arduino-based temperature and humidity monitoring system for small cold storage of fruit and vegetable. The system mainly includes hardware and software parts. Handware component includes Arduino Mega2560, ESP8266, Zigbee, DHT11 temperature and humidity sensor, and OLED display and the software component includes the Arduino IDE, UartAssist serial debugging assistant, Lighting. Blinker. Finally, the whole system is tested, and the test results show that the system has the characteristics of remote viewing, high measuring accuracy and convenient use, and the system could meet the needs of temperature and humidity management for small cold storage.

Glycine betaine treatment alleviates loss of aroma-related esters in cold-stored ‘Nanguo’ pears by regulating the lipoxygenase pathway

Glycine betaine (GB) is known to alleviate chilling injury in many fruit species. Therefore, we studied how GB affects the biosynthesis of esters in ‘Nanguo’ pears. Based on the kinds of esters, total esters, and the quantity of the main esters, it was evident that aroma losses were alleviated by GB treatment. In addition, unsaturated fatty acids contents (linoleic and linolenic acid) and the activities of lipoxygenase (LOX) and alcohol acyltransferase (AAT) enzymes were also increased. Meanwhile, comparing with the control fruit, the genes directly involved in ester synthesis were up-regulated in the GB-treated fruit. In addition, an increase in the activities and gene expression of antioxidant enzymes was observed in the treated samples. Thus, GB treatment promotes the synthesis of esters by regulating the LOX pathway and increasing antioxidant capacity, thereby effectively improving the quality of esters in cold-stored fruit.

Bruise Damage of Pomegranate during Long-term Cold Storage: Susceptibility to Bruising and Changes in Textural Properties of Fruit

ABSTRACT This study evaluated the bruise susceptibility of pomegranate fruit and textural properties of impact bruised fruit during long-term storage. Pomegranate fruit were stored at 5ºC and 85% relative humidity for 90 d. Impact tests were performed by dropping fruit from three drop heights (20, 40, and 60 cm) onto a flat hard surface to obtain different impact energy levels. The energy absorbed at impact, bruise volume (BV, mm3), bruise area (BA, mm2) and bruise susceptibility (BS, mm3/mJ) of pomegranate fruit were determined at 30 d interval for each impact dropped fruit. Textural properties for whole bruised and control (non-bruised) cold-stored fruit were carried out at 14 d intervals to determine the mechanical strength based on compression, cutting and puncture resistance tests. Based on impact tests, the increase in BV and BA of pomegranate fruit with increased drop heights and duration of cold storage were found significant (p < .05) during the first 2 months of storage and then decreased in the last month of storage time. Pearson correlations indicated a strong linear relationship between the increase in both BV and BA with an increase in impact energy throughout the 90 d storage period. Fruit puncture resistance and whole fruit cutting force, cutting energy and power as well as fruit compression strength properties; firmness, and related textural properties increased with higher impact bruising and prolonged storage. The results obtained in this study demonstrate that long-term storage, indeed, influenced the susceptibility of pomegranate fruit to bruise, and altered fruit texture.

Change in taste-altering non-volatile components of blood and common orange fruit during cold storage.

Cold storage may cause changes in the volatile and non-volatile components of orange fruit, in association with the decrement of the characteristic fruit flavour and sensory acceptability. The aim of this work was to evaluate the changes of some non-volatile taste-altering components (total and individual sugars, acids, anthocyanins, putrescine and limonin) that may affect the organoleptic perception of cold-stored orange fruit. Three blood orange varieties ('Tarocco TDV', 'Tarocco Gallo', and 'Moro') and a common variety ('Washington navel') were stored at 6±1°C and 90-95% Relative Humidity (RH) for 60 d. Chemical and sensory assessments were performed during fruit storage at 15 d intervals. During storage, no dramatic change of the physicochemical parameters was recorded and the ascorbic acid content remained almost unchanged in all varieties. As expected, total anthocyanins significantly increased during storage. Limonin significantly decreased in all varieties. A consistent and significant increase in putrescine occurred during storage in the fruit of the pigmented varieties, not recorded in the common orange variety. Putrescine behaviour showed direct correlation with the accumulation of off-flavour in cold-stored 'Moro' and 'T. TDV' fruit, showing a clear influence of its relative concentration on the sensory perception of fruit. Finally, principal component analysis showed that the complete quality profile of the four investigated varieties represented clear differentiation without overlapping clusters. Our results suggest that the arise of a negative sensory perception in cold stored blood orange fruit might be linked to their accumulation of putrescine.

Low-temperature stress-induced aroma loss by regulating fatty acid metabolism pathway in ‘Nanguo’ pear

Low temperatures retard postharvest ripening and prolong the supply period of ‘Nanguo’ pears. However, quality deterioration, or more specifically, a faded aroma occurs in long-term cold-stored fruits. To understand the implicit mechanism, we analyzed the change in content of the main aroma esters and fatty acids by chromatography–mass spectrometry (GC–MS), and the expression patterns of the main genes in fatty acid metabolism pathways. The results showed that hexyl hexanoate disappeared completely and the content of five other aromas declined significantly in cold-stored fruit during the optimal taste period. The content of saturated and unsaturated fatty acids significantly increased and decreased, respectively in cold-stored fruit. fadD, fadE, fadJ, atoB, fabF, SCD, FAD2, LOX2S, LOX1_5 and HPL genes down-regulated in fatty acid metabolism during shelf life in the fruit after cold storage. In conclusion, the faded aroma of cold-stored fruit was mainly regulated by fatty acid metabolism pathway.

Determination of H+ and Ca2+ fluxes in cold-stored banana fruit using non-invasive micro-test technology

Ion concentration changes significantly under stress conditions such as chilling. Accurate assessment of the concentration, flow velocity and flow direction of ions is pivotal to understanding the mechanism of stress response of fruits and vegetables. Fibroin is a newly reported edible coating material effective in delaying fruit senescence and alleviating chilling injury. In the present study, banana fruit were fibroin-treated before cold-stored, and non-invasive micro-test technology (NMT) was employed to determine H+ and Ca2+ fluxes across the non-wound surfaces of pericarp cuboids of the fibroid-treated banana fruit. When the wound surfaces of banana pericarp cuboids were coated with food grease, H+ and Ca2+ fluxes across the wound surfaces fluctuated around 0 nmol m−2 s-1, indicating that ion flow across the wound surfaces of the pericarp cuboids had been completely prevented by food grease coating. This coating method was employed to coat the wound surfaces while H+ and Ca2+ fluxes across the normal surfaces of the pericarp cuboids of fibroin-treated cold-stored banana fruit were determined. The results suggested that fibroin treatment alleviated chilling injury by reducing H+ and Ca2+ effluxes. Utilization of food grease coating on wound surfaces will greatly improve our ability to reveal the mechanism of chilling injury in fruits and vegetables by learning ion fluxes in tissues and organs.

Integrative comparative analyses of metabolite and transcript profiles uncovers complex regulatory network in tomato (Solanum lycopersicum L.) fruit undergoing chilling injury

Tomato fruit are especially susceptible to chilling injury (CI) when continuously exposed to temperatures below 12 °C. In this study, integrative comparative analyses of transcriptomics and metabolomics data were performed to uncover the regulatory network in CI tomato fruit. Metabolite profiling analysis found that 7 amino acids, 27 organic acids, 16 of sugars and 22 other compounds had a significantly different content while transcriptomics data showed 1735 differentially expressed genes (DEGs) were down-regulated and 1369 were up-regulated in cold-stored fruit. We found that the contents of citrate, cis-aconitate and succinate were increased, which were consistent with the expression of ATP-citrate synthase (ACS) and isocitrate dehydrogenase (IDH) genes in cold-treated tomato fruit. Cold stress promotes the expression of ACS and IDH which may increase the synthesis of citrate, cis-aconitate and succinate. Alanine and leucine had increased contents, which may result from alanine aminotransferase (ALT) and branched-chain amino acid aminotransferase (BcAT)’s high expression levels, respectively. Overall the transcriptomics and metabolomics data in our study explain the molecular mechanisms of the chilling injury and expands our understanding of the complex regulatory mechanisms of a metabolic network in response to chilling injury in tomato fruit.

Comparative Transcriptome Profiling in a Segregating Peach Population with Contrasting Juiciness Phenotypes.

Cold storage of fruit is one of the methods most commonly employed to extend the postharvest lifespan of peaches ( Prunus persica (L.) Batsch). However, fruit quality in this species is affected negatively by mealiness, a physiological disorder triggered by chilling injury after long periods of exposure to low temperatures during storage and manifested mainly as a lack of juiciness, which ultimately modifies the organoleptic properties of peach fruit. The aim of this study was to identify molecular components and metabolic processes underlying mealiness in susceptible and nonsusceptible segregants. Transcriptome and qRT-PCR profiling were applied to individuals with contrasting juiciness phenotypes in a segregating F2 population. Our results suggest that mealiness is a multiscale phenomenon, because juicy and mealy fruit display distinctive reprogramming processes affecting translational machinery and lipid, sugar, and oxidative metabolism. The candidate genes identified may be useful tools for further crop improvement.

De Novo Analysis Reveals Transcriptomic Responses in Eriobotrya japonica Fruits during Postharvest Cold Storage.

Cold storage is the primary preservation method of postharvest loquat fruits. However, cold storage also results in many chilling injury physiological disorders called lignification, which decreases the quality and economic value of the fruits. Few studies to date have focused on the transcriptomic responses associated with lignification except lignin synthesis pathways. This study aimed to explore the changes of loquat transcriptome during long-term cold storage. Our results showed that the gene expression patterns were differed among the five stages. The differentially expressed genes (DEGs) in response to cold storage were more intense and complex in earlier stage. The membrane-related genes preferentially responded to low temperature and were followed by intracellular-located genes. The cold-induced pathways were mainly concerned with signal transduction and secondary metabolism (i.e., lignin, pectin, cellulose, terpenoid, carotenoid, steroid) in the first three stages and were chiefly related to primary metabolism in the later two stages, especially energy metabolism. Further investigation suggested that 503 protein kinases, 106 protein phosphatases, and 40 Ca2+ signal components were involved in the cold signal transduction of postharvest loquat fruits. We predicted a pathway including 649 encoding genes of 49 enzymes, which displayed the metabolisms of major sugars and polysaccharides in cold-stored loquat fruits. The coordinated expression patterns of these genes might contribute to the changes of saccharides in the pathway. These results provide new insight into the transcriptomic changes of postharvest loquat fruits in response to cold storage environment, which may be helpful for improving the postharvest life of loquat in the future.

Ethylene altered fruit cuticular wax, the expression of cuticular wax synthesis-related genes and fruit quality during cold storage of apple (Malus domestica Borkh. c.v. Starkrimson) fruit

To investigate the impact of ethylene in regulating wax synthesis-related gene expression and the consequent fruit quality changes during cold storage, four key apple wax synthesis genes from ‘Starkrimson’ apple, MdCER4, MdCER6, MdWSD1 and MdMAH1, were identified, and their expression levels in response to treatments with ethephon and 1-methylcyclopropene (1-MCP) during cold storage were studied. The fruit quality changes in these two treatments were also determined during cold storage. The results showed that ethephon increased cuticular wax density, accelerated wax crystal melting and fruit senescence during cold storage of ‘Starkrimson’ apple, while 1-MCP delayed these processes. The results also showed that ethephon increased the expression levels of MdCER6 (a key gene in very long chain fatty acids synthesis), MdCER4 and MdWSD1 (two key genes in the alcohol-forming pathway of wax synthesis), while 1-MCP decreased their expression. In addition, neither ethephon nor 1-MCP regularly regulated the expression of MdMAH1, a key gene in the final step of the alkane-forming pathway of wax synthesis. Therefore, it was concluded that ethylene altered fruit cuticular wax composition and crystal morphology via MdCER6 and the subsequent alcohol-forming pathway, thus affecting the fruit quality to some extent during ‘Starkrimson’ apple fruit cold storage.

Postharvest shelf life of mango fruits stored in a CoolbotTM cold room

The Coolbot(TM) technology is an innovative cold storage technology promoted among smallholder farmers as a low-cost alternative to conventional cold rooms. The objective of the present study was to establish the efficacy of a Coolbot(TM) cold room to preserve quality and extend shelf life of mango fruits. The study was conducted in a participatory approach with smallholder mango farmers in Makueni County of Kenya between 2014 and 2015. Fruits of a popular mango cultivar (‘Apple’) were harvested from commercial farms, selected for uniformity and separated into two batches of 100 fruits each. One batch was stored in the Coolbot(TM) cold room with the temperature set at 10±2°C. The second batch was stored at ambient room temperature (24-35°C). A random sample of five fruits was drawn from each storage condition every three days to evaluate ripening-related changes including, respiratory activity, peel/flesh color and firmness, total soluble solids, titratable acidity and weight loss. The shelf life of mango fruits which were stored in the Coolbot(TM) cold room was extended by 23 days compared to fruits under ambient room conditions. Cold storage significantly (p<0.05) reduced the respiratory activity of the stored fruits. At the end stage (day 12) ‘Apple’ mango fruits stored at ambient room conditions had a respiration rate of 53.9 mL kg-1 h-1 compared to 40.5 mL-1 kg-1 h-1 for cold-stored fruits. The lower respiration rate was mirrored positively in other ripening-related changes including peel/flesh firmness and colour confirming the efficacy of the Coolbot(TM) technology as a low-cost alternative to the expensive conventional cold rooms.

A Prunus persica genome-wide RNA-seq approach uncovers major differences in the transcriptome among chilling injury sensitive and non-sensitive varieties.

Chilling injury represents a major constrain for crops productivity. Prunus persica, one of the most relevant rosacea crops, have early season varieties that are resistant to chilling injury, in contrast to late season varieties, which display chilling symptoms such as mealiness (dry, sandy fruit mesocarp) after prolonged storage at chilling temperatures. To uncover the molecular processes related to the ability of early varieties to withstand mealiness, postharvest and genome-wide RNA-seq assessments were performed in two early and two late varieties. Differences in juice content and ethylene biosynthesis were detected among early and late season fruits that became mealy after exposed to prolonged chilling. Principal component and data distribution analysis revealed that cold-stored late variety fruit displayed an exacerbated and unique transcriptome profile when compared to any other postharvest condition. A differential expression analysis performed using an empirical Bayes mixture modeling approach followed by co-expression and functional enrichment analysis uncover processes related to ethylene, lipids, cell wall, carotenoids and DNA metabolism, light response, and plastid homeostasis associated to the susceptibility or resistance of P. persica varieties to chilling stress. Several of the genes related to these processes are in quantitative trait loci (QTL) associated to mealiness in P. persica. Together, these analyses exemplify how P. persica can be used as a model for studying chilling stress in plants.

Cloning and in silico and expression analyses of the heterotrimeric G protein α subunit gene (EjLGA1) from loquat (Eriobotrya japonica) fruits under cold storage with different pretreatments

ABSTRACTCold-stored fruits of the loquat (Eriobotrya japonica Lindl.) plant suffer from strong lignification, which leads to a hard texture and a crude mouthfeel of the pulp. However, the signalling mechanisms of loquat fruits under cold storage remain unclear. In this study, the heterotrimeric G protein α subunit (Gα) gene (EjLGA1) from loquat was isolated, and in silico analysis was performed. The levels of EjLGA1 expression in cold-stored loquat fruits with different pretreatments were also investigated. The largest open-reading frame of EjLGA1 is 1173 bp, encoding a polypeptide of 390 amino acids. The nucleotide and amino acid sequences of the Gα subunit are highly conserved among loquat and 48 other seed plants, indicating that the loquat Gα subunit likely has similar functions in other plants. A reliable model of the loquat Gα subunit was constructed, which revealed the structure of the subunit. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) results showed that EjLGA1 is highly expressed under cold storage, which suggests the significance of EjLGA1 function in loquat fruits in response to cold stress. However, ethephon and 1-methylcyclopropene (1-MCP) pretreatments did not regulate EjLGA1expression. These results provide new insight into the signalling mechanism in cold-stored loquat fruits.

Modified Atmosphere Packaging Enhances the Effectiveness of Coolbot™ Cold Storage to Preserve Postharvest Quality of Mango Fruits

Recently, the Coolbot™ technology was introduced to smallholder farmers in Kenya as a low-cost alternative to conventional cold rooms. The present study sought to establish the additive benefits of cold storage under Coolbot™ cold storage and modified atmosphere packaging (MAP) in mango fruits. The participatory study was conducted in Makueni County of Kenya between November 2014 and July 2015. The mango fruits (variety ‘Apple mango’) were harvested at mature green stage from commercial orchards owned by smallholder farmers. The fruits were selected for uniformity and randomly separated into four batches which were subjected to four different treatments (storage conditions). The treatments included fruits packaged using Activebag® MAP or not packaged and either stored in the Coolbot cold room or at ambient room conditions. A random sample was taken at regular intervals from each of the four storage environments and evaluated for ripening and quality related changes during storage. The parameters evaluated included physiological weight loss, respiration, firmness, color, sugars and vitamin C. Results showed that cold storage extended the shelf life of mango fruits by 23 days without MAP and 28 days with MAP, in comparison to storage at ambient room conditions. Slow ripening under cold storage (with and without MAP) was evidenced by lower rates of respiration, softening, color changes and sugars accumulation compared to ambient room conditions. In addition, cold-stored mango fruits maintained better nutritional quality as evidenced by higher vitamin C levels, 59.77 mg/100mL and 51.8 mg/100mL with and without MAP respectively at the end of storage (day 40 and 35). This was significantly higher (p&amp;lt;0.05) compared to 55.17 and 51.53 mg/100 mL vitamin C for MAP packed and unpacked fruits at the end of storage under ambient room conditions (day 12). The results demonstrate the additive benefit of MAP and cold storage to preserve postharvest quality and extend the shelf life of mango fruits.

Efficacy of coupling gamma irradiation with calcium chloride and lemongrass oil in maintaining guava fruit quality and inhibiting fungal growth during cold storage

Abstract This study was performed to explore the efficacy of combining more than one postharvest treatment in maintaining some quality attributes and reducing fungal pathogenicity in cold-stored guava fruits. The investigated postharvest treatments included the control, CaCl2 (4%), lemongrass oil (2 dm3 kg−1), gamma (γ) irradiation (0.2, 0.4 and 0.6 kGy), 0.4 kGy γ irradiation + CaCl2 (4%), and 0.4 kGy γ irradiation + lemongrass oil (2 dm3 kg−1). The studied physiochemical attributes included weight loss, decay percentage, fruit firmness, total soluble solids (TSS), titratable acidity (TA), and vitamin C content. Different fungal species were also isolated from decayed fruits and were identified as Alternaria alternata, Alternaria solani, Aspergillus niger, Botrytis cinerea, Fusarium solani and Rhizopus stolonifer. The severity of infection for the different fungi was determined, and an in vitro antifungal assay was conducted for lemongrass oil. All the investigated treatments generally reduced decay and water loss percentages, and controlled TSS, TA and vitamin C decrements that occurred during cold storage. On the other hand, higher irradiation doses generally increased fruit softness, and the 0.4 kGy γ dose did not contribute to the overall fruit quality when coupled with CaCl2 and lemongrass oil, compared to CaCl2 and lemongrass oil treatments alone.

Glycine betaine treatment alleviates chilling injury in zucchini fruit (Cucurbita pepo L.) by modulating antioxidant enzymes and membrane fatty acid metabolism

The effect of glycine betaine (GB) treatment on chilling injury (CI) and its relation with the physiological response of zucchini fruit to chilling tolerance have been investigated. GB treatment significantly reduced postharvest CI of zucchini fruit at the concentration of 10 mmol L–1 during a fifteen-days period of storage at 1 ℃ followed by an additional three days at 20 ℃. CI index, the activities of lipoxygenase (LOX) and plant phospholipase D (PLD), proline content and fatty acid composition were assessed. The activities of various antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were essayed along with their regulatory gene transcript levels. Results suggested that amelioration of CI in zucchini fruit by GB treatment was associated with the accumulation of proline and the reduction in lipid peroxidation. Meanwhile, GB-treated fruit also showed lower levels of palmitic acid and stearic acid, and lower LOX and PLD activities, but higher activity levels of enzymes related to proline metabolism such as △1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine d-aminotransferase (OAT). Both gene expressions and antioxidant enzyme activities of SOD, CAT and APX in GB-treated fruit were significantly higher than that of control fruit. Thus, exogenous GB treatment could alleviate CI in cold-stored zucchini fruit through improved antioxidant enzymatic mechanisms. Principal component analysis (PCA) indicated that GB treatment possessed a better performance to delay chilling injury of zucchini fruit based on antioxidant levels and fatty acid metabolism than control fruits during 9 d of storage.

Role of Melatonin in Cell-Wall Disassembly and Chilling Tolerance in Cold-Stored Peach Fruit.

Melatonin reportedly increases chilling tolerance in postharvest peach fruit during cold storage, but information on its effects on cell-wall disassembly in chilling-injured peaches is limited. In this study, we investigated the role of cell-wall depolymerization in chilling-tolerance induction in melatonin-treated peaches. Treatment with 100 μM melatonin alleviated chilling symptoms (mealiness) characterized by a decrease in fruit firmness and increase in juice extractability in treated peaches during storage. The loss of neutral sugars, such as arabinose and galactose, in both the 1,2-cyclohexylenedinitrilotetraacetic acid (CDTA)- and Na2CO3-soluble fractions was observed at 7 days in treated peaches, but the contents increased after 28 days of storage. Atomic-force-microscopy (AFM) analysis revealed that the polysaccharide widths in the CDTA- and Na2CO3-soluble fractions in the treated fruit were mainly distributed in a shorter range, as compared with those in the control fruit. In addition, the expression profiles of a series of cell-wall-related genes showed that melatonin treatment maintained the balance between transcripts of PpPME and PpPG, which accompany the up-regulation of several other genes involved in cell-wall disassembly. Taken together, our results suggested that the reduced mealiness by melatonin was probably associated with its positive regulation of numerous cell-wall-modifying enzymes and proteins; thus, the depolymerization of the cell-wall polysaccharides in the peaches treated with melatonin was maintained, and the treated fruit could soften gradually during cold storage.

Optimization of the formulation of chitosan edible coatings supplemented with carotenoproteins and their use for extending strawberries postharvest life

The aim of this study was to prepare chitosan (CS) edible films containing shrimp carotenoproteins (CP) and plasticized with glycerol and polyvinyl alcohol (PVA) using the casting method. The effects of CS (1–3%), glycerol (0–10%) and CP (0–3%) amounts on mechanical properties, antioxidant and antimicrobial activities of CS-CP composite films (CSCPFs) were studied using response surface methodology (RSM). The structural properties of CSCPFs were greatly influenced by CS, then by glycerol and CP amounts. According to the best fit and response surfaces, the optimized conditions were found to be 2.43% of CS, 9.93% of glycerol and 0.005% of CP. These conditions allow obtaining the highest elongation at break (149.11%) and tensile strength (24.07 MPa), as well as good antibacterial, antifungal and antioxidant activities of 20.64 mm, 21.93 mm and 51.08%, respectively.Due to their important antioxidant and antimicrobial properties, CS (1.5%) and CS-CP (1.5%–1%) edible coatings were used for strawberries preservation. Microbiological quality and physicochemical properties (pH, weight loss and titrable acidity) were evaluated during storage at 4 °C for 11 days. Results showed that CS and CS-CP coatings were effective on reducing the fungal decay (45–50%), as compared to the uncoated fruits (75%). In addition, it was observed that the weight loss of CS and CS-CP coated strawberries was significantly lower than that of the uncoated ones. Furthermore, phytopathogenic growth on the surface of cold-stored fruits was significantly inhibited for the coated fruits, which extend the strawberries shelf life during storage. Based on our findings, CS and CS-CP showed potential coatings for controlling food-borne bacteria and natural microorganism growth during the cold storage of strawberries.

Quality and postharvest-shelf life of cold-stored strawberry fruit as affected by gum arabic (Acacia senegal ) edible coating

The impact of gum arabic (GA) (10 and 15% w/v) on the quality and postharvest-shelf life of strawberry at storage condition of 4 ± 1°C for 10 days were evaluated. Significant (p < .05) differences were found for the overall 15% GA-coating as compared with the control. The application of GA-coatings maintained the total contents of phenolic, anthocyanin and total soluble solid (TSS) but significantly (p < .05) retarded the increase in polyphenol oxidase (PPO) activity, reduced weight loss, and completely inhibited fungal infections. Moreover, the 15% GA edible coating retained the color, improved the firmness, and increased antioxidant activity compared with control. Likewise, sensory analysis results also showed the effectiveness of 15% GA-coating by retaining the quality of strawberry fruits. The results show that 15% of GA-coating can be an effective strategy for enhancing the quality of strawberry fruits during cold storage without any negative effect. Practical applications The edible coating has demonstrated to be a promising food preservation method and is progressively used for the commercial processing of many fruits and vegetables. However, gum arabic has not been used for preserving the quality of highly perishable fruit such as strawberries. The result suggests that gum arabic coatings can be a valuable biochemical means of preserving strawberries during refrigerated storage and could be used as an alternative to the synthetic formulas of fruit and vegetable packaging. Thus, gum arabic coating could provide horticultural and food processors a useful way to improve the quality, prolong shelf life, and marketing strategy.

Impact of postharvest exogenous γ-aminobutyric acid treatment on cucumber fruit in response to chilling tolerance.

Low-temperature storage is generally used to extend postharvest lifetime and to inhibit decay of cucumber fruit, but it also enhances the intensity of chilling injury. The capability of γ-aminobutyric acid to enhance antioxidant enzyme activities and reduce chilling injury was studied in cucumber (Cucumis sativus L.) fruit stored at 1°C for 5weeks. The purpose of this study was to define if the GABA-induced modification in antioxidant system and phospholipase activity is linked to the reduced chilling injury in cold-stored cucumber fruit. Alleviation of chilling injury by GABA treatment was related to increased content of proline, endogenous GABA and enhanced activities of CAT and SOD, together with reduced activities of PLC, PLD and LOX. We suggest that PLC, LOX and PLD are associated with chilling injury initiation by involvement in a signaling pathway and membrane deterioration. Therefore the results obtained in this study suggest GABA's potential for postharvest applications for reducing chilling injury symptom in cucumber fruit.