Maintained Fruit Firmness Research Articles

Postharvest application of sodium nitroprusside improves the quality of ‘Umran’ ber fruit under cold storage conditions by regulating enzyme activities

ABSTRACT Ber fruit is highly perishable, with a storage life of only 3–5 days under ambient conditions, which makes it difficult to transport the fruit even to domestic markets. An experiment was conducted to study the effect of postharvest treatment with sodium nitroprusside (50, 100 and 150 µM) on the storage life, quality attributes, bioactive composition and antioxidant enzyme contents of ‘Umran’ ber fruit. The treated fruit were stored for 28 days to investigate the effects of sodium nitroprusside after 7 days of cold storage at 7.5°C and 90–95% RH. It was found that fruit treated with 100 μM sodium nitroprusside experienced lower fruit weight loss and spoilage, maintained fruit firmness, and had a higher sensory quality, phenolic content, carotenoid content, soluble solids content, sugar content, ascorbic acid and antioxidant activity than the control. Furthermore, the activities of the cell wall degrading enzymes polygalacturonase, polyphenol oxidase, pectin methyl esterase and catalase were lower, while the activities of superoxide dismutase and peroxidase enzymes were higher in the treated fruit. Therefore, treatment with 100 μM sodium nitroprusside shows high potential for improving the storage life and maintaining the quality attributes of ber fruit for up to 21 days under cold storage.

Effect of pre-harvest application of potassium nitrate, naphthalene acetic acid and ethephon on ripening and shelf-life of guava cv. Allahabad Safeda

The current study, effect of pre-harvest application of potassium nitrate (KNO3), naphthalene acetic acid (NAA) and ethephon on ripening and shelf-life of guava (Psidium guajava L.) cv. Allahabad Safeda was undertaken at the Fruit Research Farm, Dr B R S Agri at Sri Muktsar Sahib, Punjab. The experiment was carried out on an eight-year-old guava tree of the Allahabad Safeda. The trees were sprayed with various doses of chemicals, KNO3 (1.0, 1.5, 2.0%), NAA (200, 300, 400 ppm) and ethephon (200, 400, 600 ppm) during the third week of November. The fruits were harvested at the hard ripe stage on 19 December, placed in Corrugated fibre box (CFB) of 4 kg capacity and stored at ambient temperature. In ambient storage, guava fruits were remain acceptable for up to 6 days of storage without any adverse effect on fruit quality. KNO3 (1.5 and 2.0%), NAA (300 ppm) and ethephon (200 ppm) recorded a reduction in physiological loss of weight and spoilage and KNO3 (2.0%) maintaining fruit firmness (7.64 kg/cm2), palatability rating (8.00) throughout the storage period. However, the highest storage life and good-quality fruits was recorded with the application of KNO3 (1.5, 2%) during ambient storage. At lower concentrations, ethephon also helps to enhance the ripening of fruits, contrast to this fruits treated with NAA delayed the fruit senescense.

Chlorogenic Acid as a Promising Tool for Mitigating Chilling Injury: Cold Tolerance and the Ripening Effect on Tomato Fruit (Solanum lycopersicum L.).

Tomato fruit (Solanum lycopersicum L.) has a very brief storability, displaying chilling injury (CI) when stored in cold conditions used to delay ripening. For this reason, in this study, different concentrations (10, 50, and 100 mg L-1) of chlorogenic acid (ChA) were assayed to evaluate its effectiveness in maintaining fruit quality traits and mitigating CI symptoms in tomatoes. Our results showed that ChA treatments effectively delayed weight loss and maintained fruit firmness, with optimal results observed at 50 mg L-1. In general, higher concentrations did not result in significant quality improvements. Additionally, ChA-treated tomatoes exhibited reduced values in malondialdehyde (MDA) content and electrolyte leakage (EL), indicating improved membrane integrity and reduced oxidative damage. ChA treatments also maintained a higher total phenolic content (TPC) during storage, with significant levels of individual polyphenols such as rutin, neochlorogenic acid, and p-coumaric acid, suggesting enhanced antioxidant capacity and better preservation of fruit quality. This is the first time the potential of ChA to reduce CI has been evaluated in any fruit species, and its impact in tomato ripening is shown to uphold fruit quality during cold storage, prolonging the storability of tomatoes. In particular, we highlight its natural origin and effectiveness as a postharvest treatment.

Postharvest short-time partial dehydration extends shelf-life and improves the quality of Actinidia arguta during low temperature storage

Actinidia arguta is a type of kiwi fruit with a smooth glabrous shape, which provides high nutritional value, a sweet and sour taste, and excellent healthcare function. However, it is a typical climacteric fruit and decomposes quickly when stored. For delaying senescence, the effect of postharvest short-time partial dehydration (STPD) on the storage quality of A. arguta was investigated under dehydration rates of 2%, 4%, and 6% coupled with storage at (2.0 ± 0.5) °C, respectively. Results showed that appropriate dehydration treatment coupled with low temperature storage inhibited the pectinase activity and the decomposition of propectin, thus maintaining fruit firmness, reducing fruit decay rate, regulating the generation of abscisic acid (ABA) delaying ethylene production, and decreasing the peak level of respiration rate. It also inhibited the reduction of total soluble solid, titratable acid, and vitamin C, maintains catalase and peroxidase activity. Based on the present study, the 4% dehydration treatment was the most effective, which extended the storage period up to 60 days and reduced the decay rate to 33%. In conclusion, it was revealed that STPD could be an effective method for retarding the losses that occurred in the fruit quality of A. arguta during cold storage.

Thymol application delays the decline of fruit quality in blueberries via regulation of cell wall, energy and membrane lipid metabolism

In this study, we evaluated the potential for exogenous thymol to slow this decline by measuring the effects of thymol application on cell wall, energy, and membrane lipid metabolism. The results showed that thymol application improved the preservation of the total soluble solids, titratable acidity, decay rate, and anthocyanin content, and effectively inhibited the accumulation of O2·-, H2O2, and malondialdehyde in blueberries during storage. Thymol application also effectively maintained fruit firmness, cell wall structure, and energy levels, while delaying the degradation of membrane phospholipids and unsaturated fatty acids during the storage of post-harvest blueberries. Therefore, exogenous thymol can maintain the quality of blueberry fruits by regulating energy and membrane lipid metabolism and reducing cell wall degradation. Thus, thymol-treatment could be a suitable biocontrol agent for maintaining blueberry quality and extending blueberry fruit storage life.

γ-Aminobutyric acid delays fruit softening in postharvest kiwifruit by inhibiting starch and cell wall degradation

The effects of 10 mM γ-aminobutyric acid (GABA) treatment on fruit softening, starch degradation, cell wall disassembly in cold-stored ‘Hongyang’ kiwifruit after harvest were investigated. The results depicted that GABA treatment maintained firmness and delayed fruit softening during storage by retaining high starch content due to the inhibition of the transcription levels of related starch-degrading genes, such as AcGWD, AcPWD, and AcBAMs. In addition, compared with the control, higher level of chelated-soluble pectin, Na2CO3-soluble pectin, hemicellulose and cellulose content but lower water-soluble pectin content were observed in the treated kiwifruit as GABA suppressed cell wall breakdown by down-regulating the expression of AcPE, AcPG, AcBGALs, and AcXTHs. In summary, our results indicated that exogenous GABA contributes to maintaining fruit firmness, delaying softening in postharvest kiwifruit by inhibiting starch degradation and preserving cell wall metabolism.

Carnauba wax-based edible coatings retain quality enhancement of orange (Citrus sinensis cv. Moro) fruits during storage

Fruit coatings serve a dual purpose in preserving the quality of fruits. Not only do they act as a barrier against water evaporation and fungal infiltration, but they also enhance the fruit’s visual appeal in the market. Yet, their influence on the fruit’s quality components, which play a crucial role in determining its nutritional value, taste, and overall flavor, has remained relatively unexplored. This study aimed to evaluate the effects of carnauba wax coating on the quality of Moro oranges during storage. The selected fruits were meticulously chosen for uniformity in size. The experiment involved applying carnauba wax, a commonly used type among local producers, at four different concentrations: 0%, 0.5%, 1%, and 1.5%. These treatments were applied during various storage periods, including immediately after fruits were harvested and after 40 and 80 days. Following the application of these treatments, the oranges were stored in a controlled environment (morgue) at a temperature of 4 ± 1 °C. Subsequently, several physicochemical parameters of both the fruit flesh and skin were examined. The results unveiled a decline in the overall ascorbic acid content of the fruits. In terms of phenol content, a general decreasing trend was observed after harvesting. At each sampling interval during storage, the phenol content in uncoated fruits consistently exceeded that of their waxed counterparts. Significant reduction in fruit weight was observed throughout the storage period. Both vitamin C and total acidity levels in the fruit exhibited decreases during the storage period. As time passed, fruit firmness gradually declined, while fruit decay increased during the 40- and 80-day storage periods for untreated Moro oranges. The anthocyanin content showed an increasing trend. The study also unveiled a decline in the antioxidant capacity of citrus fruits during storage. Strong significant positive correlations were observed between total phenol content and key parameters, such as antioxidant activity (0.941**), MDA (0.364*), vitamin C content, and total carbohydrate content (0.475**). Skin radiance showed a perfect correlation with chroma and hue (1.000**). Principal component analysis revealed that the first principal component accounted for 34.27% of the total variance, out of a total of five principal components that explained 77.14% of the variance. Through cluster analysis, the variables were categorized into three distinct groups; one associated with weight loss and another with ion leakage. Considering these findings, carnauba wax-based coating emerges as a promising solution for preserving Moro oranges. It effectively mitigates fruit weight loss and helps maintain fruit firmness during storage, making it a valuable tool for fruit preservation.

FISIOLOGÍA DE LA MADURACIÓN Y MANEJO EN POSTCOSECHA DE FRUTILLA CHILENA (Fragaria chiloensis)

The Chilean strawberry (Fragaria chiloensis) is a native species to Chile. Consumers value this fruit for its organoleptic properties, but it is highly perishable. Since it is a non-climacteric fruit, harvesting at the optimum ripening stage is essential to ensure its quality during commercialization. In this fruit, quality is determined by appearance, flavor, aroma, nutritional value, and firmness, which changes during ripening. The species presents a high rate of firmness loss or softening, associated with the elevated enzymatic activity of cell wall-modifying enzymes of the pectin and hemicellulose fractions, such as polygalacturonase, α-arabinofuranosidase, β-galactosidase, endo-glucanase, β-xylosidase, xyloglucan endotransglycosilase/hydrolase and rhamnogalacturonan lyase at different ripening stages. Firmness is a key trait for commercialization and organoleptic quality; hence, its management during storage is necessary. Different studies have investigated the effects of pre or postharvest treatments, such as modified atmosphere packaging and exogenous applications of calcium, auxin, methyl jasmonate, chitosan, and hydrogen sulfide, which maintain fruit firmness by reducing pectin solubilization and improve other attributes responsible for organoleptic and nutritional quality during storage. This literature review focuses on the ripening biology of Fragaria chiloensis and recent findings regarding softening and its biochemical and molecular basis, as well as interventions oriented to maintain the quality and extend the shelf-life of this fruit.

IAA regulated levels of endogenous phytohormones in relation to chilling tolerance in cold-stored peaches after harvest

The effects of indoleacetic acid (IAA) treatment on chilling injury and endogenous phytohormones in peach fruit were studied. The results showed that IAA treatment decreased chilling injury index of cold-stored peaches, effectively maintaining fruit firmness and reducing the electrical conductivity level. IAA treatment upregulated the expression of IAA biosynthetic gene PpMES and signaling pathway gene PpSAUR, but reduced the transcript abundance of IAA degradative genes PpDAO, PpGH3, and PpIAMT, leading to endogenous IAA accumulation in treated peaches. Meanwhile, after IAA treatment, contents of melatonin and γ-aminobutyric acid (GABA) were also increased which was associated with the upregulation of their anabolic genes and downregulation in GABA catabolic genes. In addition, the levels of abscisic acid (ABA) and gibberellin (GA) were reduced in treated peaches due to its modification in the transcript levels of ABA and GA metabolic genes. Collectively, IAA could alleviate the symptoms of chilling injury in peach fruit via regulating contents of endogenous phytohomones such as IAA, melatonin, GABA and GA.

Chitinase-Like Protein PpCTL1 Contributes to Maintaining Fruit Firmness by Affecting Cellulose Biosynthesis during Peach Development.

The firmness of the flesh fruit is a very important feature in the eating process. Peach fruit is very hard during development, but its firmness slightly decreases in the later stages of development. While there has been extensive research on changes in cell wall polysaccharides during fruit ripening, little is known about the changes that occur during growth and development. In this study, we investigated the modifications in cell wall components throughout the development and ripening of peach fruit, as well as its impact on firmness. Our findings revealed a significant positive correlation between fruit firmness and cellulose content at development stage. However, the correlation was lost during the softening process, suggesting that cellulose might be responsible for the fruit firmness during development. Members of the chitinase-like protein (CTL) group are of interest because of their possible role in plant cell wall biosynthesis. Here, two CTL homologous genes, PpCTL1 and PpCTL2, were identified in peach. Spatial and temporal expression patterns of PpCTLs revealed that PpCTL1 exhibited high expression abundance in the fruit and followed a similar trend to cellulose during fruit growth. Furthermore, silencing PpCTL1 expression resulted in reduced cellulose content at 5 DAI (days after injection), this change that would have a negative effect on fruit firmness. Our results indicate that PpCTL1 plays an important role in cellulose biosynthesis and the maintenance of peach firmness during development.

Involvement of branched RG-I pectin with hemicellulose in cell–cell adhesion of tomato during fruit softening

Cell adhesion of four cultivars of tomato fruit, “Micro Tom (MT)”, “Heinz 1706 (H1706)”, “Money Maker (MM)”, “Ailsa Craig (AC)” were evaluated and cell walls were analyzed in order to assess the possible contribution of pectic and hemicellulosic polysaccharides to the softening and altered cell adhesion at two different stages of ripeness. Cell wall material (CWM) and solubilised fractions of green and red ripe fruit were analyzed by chemical, enzymatic techniques. In comparison with the four cultivars of tomato fruits, H1706 and MM are harder than MT and AC at both green and red ripe stage. The ripening-associated solubilisation of rhamnogalacturonan-riched pectic polysaccharides was reduced in H1706 and MM, and the content of side -chain sugars from RG-I reduced by more than 50% in MT and AC. In addition to recognized pectic modifying enzymes, RGase had a good effect on cell separation of H1706 and MM fruit at red ripe stage. The higher RG-I content and branching degree have been associated with increased cell adhesion and reduced cell wall porosity, thus maintained fruit firmness.

Pre-storage oxalic acid treatment inhibits postharvest browning symptoms and maintains quality of abiu (Pouteria caimito) fruit

The effect of exogenous oxalic acid (OA) treatment on browning and postharvest quality of abiu fruit was evaluated during the storage period. Abiu fruit was soaked in water (control), 5 mM oxalic acid (OA5), and 10 mM oxalic acid (OA10) for 10 min and air-dried, and then stored in an ambient room (28 ± 1 °C and 80 ± 5% RH) for 12 days. The results showed the peel browning in control, and the OA5-treated reached 30% on day-6 of the storage and day-12 storage for the OA10-treated. In addition, the browning symptoms in abiu pulp reached 30% on day-3, day-6, and day-9 storage, for control, OA5, and OA10, respectively. The exogenous OA10 treatment in abiu fruit could suppress the oxidation of phenolic compounds and inhibit an increase in polyphenol oxidase (PPO) enzyme activity and malondialdehyde (MDA) content during storage. In addition, applying the OA10-treated in abiu fruit could reduce 1-aminocyclopropane-1-carboxylic (ACC) concentration, ethylene production, respiration rate, and delay the occurrence of the climacteric peak. The exogenous OA10 treatment in abiu fruit could also reduce fresh weight loss, titratable acidity (TA), ascorbic acid, and maintain fruit firmness during storage. Therefore, the exogenous OA10 treatment could be considered an appropriate treatment to delay browning and preserve the quality of the abiu fruit.

Melatonin Treatment Affects Wax Composition and Maintains Storage Quality in 'Kongxin' Plum (Prunus salicina L. cv) during Postharvest.

Cuticular wax is an essential barrier against biological and abiotic stress and is also an important factor affecting fruit storage quality. This paper investigated the effect of melatonin treatment on cuticular wax and the storage quality of plum fruit at low temperature storage of 4 ± 1 °C. 'Kongxin' plum was treated with 150 μmol·L-1 melatonin, dried overnight at room temperature 25 ± 1 °C, and then stored at 4 ± 1 °C for 40 d. The microstructure of the fruit epidermis was examined after 0, 20, and 40 d of storage, and the wax composition and fruit storage quality were measured at 10 d intervals. The results demonstrated that melatonin promoted the disintegration and thickening of rod-shaped waxy crystals of 'Kongxin' plum fruit and inhibited the combination of disintegrated wax and inner wax. Melatonin maintained fruit firmness and decreased the correlation between fruit firmness and other storage quality parameters. The correlation between firmness and wax composition was enhanced. Melatonin promoted long-chain alkanes that were positively correlated with firmness and water retention and strengthened the correlation between the length of the alkane chain and storage quality parameters but reduced the difference between alkane isomers and storage quality parameters.

Pulsed light reduces postharvest losses of Chinese bayberries by affecting fungal microbiota during cold storage

Non-thermal sterilization technology is considered a safe and effective approach in controlling postharvest losses of fruit. In this study, the effects of pulsed light (PL) on qualities of Chinese bayberries during storage at 10 °C, 95% RH for 12 d were investigated. At the same time, high-throughput sequencing was operated to identify fungal microbiota on Chinese bayberries. The results showed that PL treatment could inhibit the decay incidence and polyphenol oxidase (PPO) activity, maintain fruit firmness and enhance phenylalanine ammonia-lyase (PAL) activity, with no effect on titratable acid (TA), total soluble solids (TSS), malondialdehyde (MDA) content and superoxide dismutase (SOD) activity. Additionally, the PL treatment maintained alpha diversity and altered beta diversity. At the species level, the abundance of Monographella nivalis and Colletotrichum cordylinicota were reduced in PL samples, while Hanseniaspora uvarum and Diaporthe spp were enriched. M. nivalis and C. cordylinicota were positively correlated with weight loss and decay index according to canonical correspondence analysis (CCA). The data of microbial correlation network indicated that PL treatment reduced pathogenic fungal microbiotas and made fungal community more complex and steadier. This study demonstrated that PL affects fungal community by inhibiting plant pathogens, increasing the amounts of endophytes and consolidating microbial networks. It provides new insights into the dynamics of the microbiome of Chinese bayberries after PL treatment.

THE EFFICACY OF POSTHARVEST BIOCONTROL TREATMENTS IN CONTROLLING SPOILAGE OF TOMATO FRUIT IN SOUTH AFRICAN COMMERCIAL SUPPLY CHAINS

In this study, the effectiveness of postharvest biocontrol treatments using B-13 yeast isolate in controlling spoilage of tomato fruit was evaluated in selected commercial supply chains in South Africa. Mature green tomatoes were harvested from three commercial farms in Limpopo (Musina, Mooketsi and Pont drift) during summer and transported through the three supply routes to Pietermaritzburg, where four postharvest treatments were applied to the fruit, then stored in ambient and cold storage (11oC) conditions. The fruit was sampled over a 30-day storage period and its firmness, colour, weight loss, marketability and incidences of decay assessed. Fruit stored under ambient conditions had higher incidences decay, diseases and physiological disorders compared to samples stored in cold storage, with these incidences varying widely with pre-storage treatments applied on the fruit. The supply chain route significantly (p≤0.05) influenced the physicochemical and subjective quality of tomato fruit. Biocontrol treatment reduced mass loss of fruit and had comparable physicochemical and subjective attributes to chlorine treated fruit. Biocontrol treatment was also effective in maintaining fruit firmness and colour for the first eight days of storage. Biocontrol treated fruit had 7.9% and 7.7% lower mass loss compared to control and chlorine fruit treated fruit, respectively. Although, biocontrol treatment showed promising prospects in controlling tomato spoilage and improving its shelf life, integrating it with other treatments should be further tested to improve its efficacy.

Essential oils nano-emulsion confers resistance against Penicillium digitatum in 'Newhall' navel orange by promoting phenylpropanoid metabolism

Inducing natural resistance against pathogen infection in postharvest citrus by exogenous elicitor is a promising alternative to reduce postharvest losses. Here, the potential induced resistance mechanism of blended cinnamaldehyde, carvacrol and eugenol nano-emulsion against P. digitatum in ‘Newhall’ navel orange (Citrus sinensis (L.) Osbeck) was evaluated through combined transcriptomic and metabolomics analysis. Application of nano-emulsion maintained fruit firmness after P. digitatum inoculation, nano-emulsion reduced H2O2 and MDA accumulation of citrus fruit, increased PAL, C4H, 4CL and CAD activity, and higher contents of flavonoids, lignin and total phenolic compounds. Furthermore, higher activities of SOD, CAT, POD and APX in nano-emulsion treated fruit possibly benefited reducing ROS accumulation and lipid peroxidation. The activities of the defense enzymes CHI, GLU were higher in the nano-emulsion treated fruits. RNA-seq identified 653 differentially expressed genes (DEGs) between the control and the nano-emulsion-treated fruit at 48 hpi, including 444 up-regulated and 209 downregulated genes. Genes encoding shikimate O-hydroxycinnamoyltransferase (HCT), caffeoyl-CoA O-methyltransferase (CCoAOMT), caffeic acid 3-O-methyltransferase / acetylserotonin O-methyltransferase (COMT), cinnamyl-alcohol dehydrogenase (CAD) and peroxidase (POD) were differentially expressed by nano-emulsion treatment. In addition, 175 differential accumulated metabolites between the control and the nano-emulsion-treated fruit at 48 hpi also were identified, the different accumulated metabolites from phenylpropanoid biosynthesis pathway related with disease resistance including L-phenylalanine, caffeic acid, caffeoyl quinic acid, coniferyl alcohol, coniferaldehyde. The integrated transcriptomic and metabolomic profiling indicated that the differentially expressed genes (DEGs) and the differentially accumulated metabolites (DAMs) were mainly involved in phenylpropanoid biosynthesis pathway. Besides, the nano-emulsion significantly induced accumulation of primary metabolites including amino acids, soluble sugars, organic acids, lipids, sugar and alcohols. All these results indicated that blended essential oil nano-emulsion as an antifungal delivery system to induce resistance against P. digitatum infection of ‘Newhall’ navel orange by promoting phenylpropanoid metabolism.

Benzothiadiazole induced changes in the transcriptome and regulation of banana fruit ripening and disease resistance

Benzothiadiazole (BTH) induces plant disease resistance and delays fruit ripening, but its possible mechanism of action remains unclear. Therefore this study investigated the effects of BTH on ripening and disease incidence in banana (Musa spp.) fruit. Our results showed that using BTH delayed ripening and maintained fruit firmness by inhibiting the enzymes involved in softening. BTH also delayed and reduced the occurrence of anthracnose caused by Colletotrichum musae during the ripening process. Transcriptome analysis identified 10,430 differentially expressed genes (DEGs) during the ripening process compared with freshly harvested fruit. Many DEGs were identified between the BTH and control group or prochloraz treatment, but only a few DEGs were found in the prochloraz treatment compared to the control group. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the DEGs induced by the BTH treatment were primarily enriched in the synthesis of terpenoid quinones, plant-pathogen interaction, plant hormone signal transduction, phenylpropanoid biosynthesis, phenylalanine metabolism, peroxisome, and fatty acid biosynthesis among other pathways. BTH also induced the expression of many transcription factor (TF) families, including those in the WRKY, NAC, MYB and bHLH families, with the WRKY family being the most enriched. The WRKY TF interacts with many ripening- and secondary metabolism-related genes to regulate fruit ripening and disease resistance. Our results showed that, compared with the fungicide prochloraz, BTH alters the transcripts of the genes related to hormone signalling, secondary metabolism and resistance in the banana peel, and key TFs, thereby delaying fruit ripening, enhancing fruit resistance, and maintaining fruit quality.

Bioefficacy of Composite Medicinal Plant Extracts and Gum Arabic on Improving Postharvest Quality in Dragon Fruit.

Several natural preservative techniques including plant extracts are used to minimize postharvest losses caused by pathogens. Our recent findings elucidated that the application of crude extracts of ginger, turmeric, and "dukung anak" (Phyllanthus niruri Linn.) alone causes phytotoxicity and adversely affects the postharvest quality of dragon fruit, especially at high concentrations. This study investigated the effect of a composite coating of 10% gum arabic (GA) and crude extracts of ginger, turmeric, and "dukung anak" separately at 5, 10, and 15 g L-1 on postharvest quality of dragon fruit stored at 11 ± 2°C, 80% RH for 28 days. After 28 days of cold storage, anthracnose was significantly reduced in fruit coated with 10% GA plus 10 or 15 g L-1 of any of the crude extracts and resolved the problem of phytotoxicity while maintaining the postharvest quality of fruit for 28 days. The reduction of anthracnose was pronounced at 10% GA+10 g L-1 of turmeric extract (38.6%) which was not significantly different at 10% GA+10 g L-1 of ginger extract compared to control (41.3%). Composite coating of 10% GA+10 g L-1 of turmeric extract maintained the postharvest quality of dragon fruit as was evident with a reduction in weight loss (2.53%), delayed degradation of titratable acids (0.15%), and maintained fruit firmness (28.72 N) and the overall acceptability of the fruit after 28 days. We conclude that incorporation of 10% GA with turmeric extract at a high concentration can serve as a potential biofungicide in postharvest management of fresh produced by reducing phytotoxicity while improving the overall acceptability of fruit.

Integrative metabolomics and transcriptomics analyses reveal pivotal regulatory mechanisms of 1-methylcyclopropene in maintaining postharvest storage quality of ‘Fuji’ apples

Abstract In this study, integrative metabolomics and transcriptomics analyses were conducted to investigate the effects of 1-methylcyclopropene (1-MCP) on apple fruit quality during long-term cold storage. The results showed that 1-MCP (1 μL/L) treatment could maintain fruits apparent quality (i.e. external color and firmness), inhibit the increase of rot rate and soluble solids content/titratable acidity ratio, decrease ethylene release, and respiratory intensity during cold storage, and extend shelf life. Moreover, 1-MCP had long-term effects on the accumulation of many qualities related to metabolite and gene expression in fruits. 1-MCP affected genes related to metabolism at the early stage of storage, specifically those of the glycolysis and tricarboxylic acid cycle pathways. Genes related to the degradation of sucrose, starch, and cellulose were inhibited, and some starch and cellulose synthesis genes were up-regulated by 1-MCP. Apart from ethylene synthesis and signal transduction being inhibited by 1-MCP, several enzymes (pectinesterase, pectate lyase, polygalacturonase) were involved in pectin degradation, and degradation products of the cell wall (i.e. d-galacturonic acid and d-glucuronic acid) were also strongly inhibited, further maintaining fruit firmness. Cysteine, as precursor glutathione (GSH) related to plant resistance, up-regulated the synthase gene. However, the expression of genes related to cyanoalanine synthase and amino acid utilization pathways was suppressed by 1-MCP. Collectively, 1-MCP could maintain the postharvest quality of apple fruits.

Salicylic acid treatment inhibits ethylene synthesis and starch-sugar conversion to maintain apple fruit quality during shelf life

Starch and sugars are widely acknowledged as taste determinants, energy substances, and signal molecules in fruits. Salicylic acid (SA) regulates many physiological and biochemical processes during fruit ripening. In this work, we investigated the effects of SA treatment on physiological parameters and SA synthesis, ethylene production, and starch-sugar metabolism of apples during shelf life. Results showed that SA maintained fruit firmness, reduced weight loss, and inhibited starch to sugar conversion during shelf life. The endogenous SA level was increased in SA-treated fruits, mediated by MdPAL, MdICS2, and MdNPR1, thus decreasing MdACS1 and MdACO1 expressions and inhibiting ethylene biosynthesis. Furthermore, the expression of starch and sugar-related genes, MdAMY, MdBam5, MdBam8, MdSPS, MdSUSY, MdNINV, and MdAINV, were inhibited by SA treatment during shelf life. It was inferred that exogenous SA could inhibit ethylene synthesis and starch-sugar conversion, maintain the quality, and prolong the shelf life of apples