Relationship among Sugars, Organic Acids, Mineral Composition, and Chilling Injury Sensitivity on Six Pomegranate Cultivars Stored at 2 °C.

Pomegranate is a sensitive fruit to chilling injury (CI) during storage at temperatures below 7 °C. However, sensitivity of pomegranate to CI is dependent on cultivar and exposure times to low temperatures. In this work, the sensitivity to CI of six pomegranate cultivars (Punica granatum L.) 'Wonderful', 'Kingdom', 'Bigful', 'Acco', 'Purple Queen', and 'Mollar de Elche', was evaluated after 30 d at 2 °C plus 2 d at 20 °C. Among cultivars, there was a great variability in the sensitivity to the appearance of CI symptoms. 'Kingdom' cultivar was the most CI sensitive and 'Mollar de Elche' cultivar was the least sensitive cultivar. CI symptoms were greater in the internal part of the skin than in the external part, although no correlation was found between ion leakage (IL) and CI severity after cold storage. However, both, external and internal CI index were correlated with the IL at harvest, with Pearson correlation of 0.63 and 0.80, respectively. In addition, this variability to CI among cultivars could also be due to composition and tissue structures in arils and peel. The solute content of the arils (anthocyanins, sugars, and organic acids, in particular citric acid), showed high correlations with CI sensitivity, with Pearson correlations (r) of 0.56 for total soluble solids, 0.87 for total acidity, 0.94 for anthocyanins, -0.94 for oxalic acid, 0.87 for citric acid, 0.62 for tartaric acid, -0.91 for malic acid, 0.8 for sucrose, and 0.71 for glucose, which can leak to the inner surface of the peel causing browning reactions. In addition, the high peel Ca/K ratio could play an important role on increasing fruit tolerance to CI, since it was negatively correlated with the internal and external CI indexes.

The Simultaneous Use of 1-Methylcyclopropene and Methyl Jasmonate Vapor as an Innovative Strategy for Reducing Chilling Injury and Maintaining Pomegranate Fruit Quality at Suboptimal Temperatures.

Spain is one of the main contributors to global pomegranate production. Pomegranate presents a challenge for preservation at suboptimal temperatures. Preserving this fruit for an extended period is challenging due to its susceptibility to chilling injury (CI). For this reason, we have examined different postharvest treatments to extend the pomegranate shelf life and their potential impact on reducing CI. For this reason, two postharvest treatments have been applied: 1-Methylcyclopropene (1000 nL L-1 1-MCP) and methyl jasmonate vapors (0.01 mM MeJA), a natural elicitor found in many plant organs that induces a wide range of physiological processes, including the activation of defense mechanisms against stress. Following the application of these treatments and subsequent fruit storage at 2 °C for 90 days, maintenance of firmness and membrane integrity was observed. Additionally, a positive synergic effect was observed in these quality traits when combining both substances (1-MCP + MeJA), especially with regard to delaying weight loss, the external color evolution, and total polyphenol accumulation. On the other hand, MeJA treatment alone or in combination with 1-MCP also increased the anthocyanin content in arils, thereby enhancing the fruit quality. In general, the best results were observed when these two different technologies were applied as a combined treatment, especially in terms of maintaining quality traits such as fruit firmness and total acidity and reducing weight loss and CI. This is the first time that these two substances have been tested together in any fruit species, and their simultaneous application in the same container represents an innovative approach that could be an interesting tool for commercial purposes.

A Synergistic Effect Based on the Combination of Melatonin with 1-Methylcyclopropene as a New Strategy to Increase Chilling Tolerance and General Quality in Zucchini Fruit.

Zucchini fruit are highly sensitive to low temperatures leading to significant peel depressions, increasing weight loss and making them impossible to be commercialized. In this study the effect on the reduction of chilling injury (CI) assaying different postharvest treatments to cv. Cronos was evaluated. We have compared the application of substances such as 1-methylcyclopropene (1-MCP) with the application of a natural origin compound as melatonin (MT), both with demonstrated activity against CI in different vegetal products. The effects of MT (1 mM) by dipping treatment of 1 h and 1-MCP (2400 ppb) have been evaluated on zucchini fruit during 15 days of storage at 4 °C plus 2 days at 20 °C. Treatments applied independently improved some fruit quality parameters in comparison with control fruit but were not able to manage CI even though they mitigated the impact on several parameters. However, when these two separated strategies were combined, zucchini cold tolerance increased with a synergic trend. This synergic effect affected in general all parameters but specially CI, being also the only lot in which zucchini fruit were most effectively preserved. This is the first evidence in which a clear positive effect on zucchini chilling tolerance has been obtained combining these two different strategies. In this sense, the combined effect of 1-MCP and MT could be a suitable tool to reach high quality standards and increasing shelf life under suboptimal temperatures.

Melatonin Pre-harvest Treatments Leads to Maintenance of Sweet Cherry Quality During Storage by Increasing Antioxidant Systems.

Melatonin has been reported to have an important role in fruit ripening, although the effect of pre-harvest melatonin treatment on sweet cherry quality properties during storage is still unknown. In the present experiments, the effects of melatonin (0.1, 0.3, and 0.5 Mm) by foliar spray treatments of 'Prime Giant' and 'Sweet Heart' sweet cherry trees on fruit quality traits and antioxidants systems during storage was evaluated. Results showed that these treatments reduced weight losses during storage, as well as losses in firmness and titratable acidity. In addition, changes in fruit colour and total soluble solid content were also delayed in fruit from melatonin treated trees with respect to controls. Moreover, in general, total phenolic and anthocyanin concentrations were higher in fruit from treated trees than in those from control ones, either at harvest or during the whole storage period. Finally, the activity of the antioxidant enzymes catalase, ascorbate peroxidase and peroxidase was also enhanced as a consequence of melatonin treatment. Overall results show that pre-harvest melatonin treatment delayed the post-harvest ripening process of sweet cherry fruit, leading to maintenance of their quality properties in optimum levels for consumption 2 weeks more with respect to fruit from control trees. Antioxidant systems, both enzymatic and non-enzymatic ones, were also enhanced by melatonin treatments, which would account for the delay on fruit post-harvest ripening process and fruit quality maintenance during storage.

Preharvest Treatment with Oxalic Acid Improves Postharvest Storage of Lemon Fruit by Stimulation of the Antioxidant System and Phenolic Content.

Lemon trees (Citrus limon (L.) Burm. F) were treated monthly with oxalic acid (OA) at 0.1, 0.5, and 1 mM from initial fruit growth on the tree until harvest in2019. The experiment was repeated in 2020, with the application of OA 1 mM (according to the best results of 2019). In both years, fruit from OA-treated trees and the controls were stored for 35 days at 10 °C. Results showed that all treatments reduced weight loss (WL) and maintained higher firmness, total soluble solids (TSS), and total acidity (TA) than in the controls. Meanwhile, colour (hue angle) did not show significant differences. The activity of antioxidant enzymes, catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) in the flavedo of the fruit from the OA-treated trees was higher than in the controls at harvest and after 35 days of storage. Similarly, the total phenolic content (TPC) in the flavedo and juice of the fruit from the OA-treated trees were higher than in the controls. The increase in the activity of the antioxidant enzymes and TPC started with the first preharvest OA treatment and were maintained during fruit development on the tree until harvest. Preharvest OA treatments enhanced the antioxidant system of the lemon fruits, reducing the postharvest incidence of decay. Thus, OA could be a useful tool to increase the quality and functional properties of lemon fruits.

Melatonin Treatment to Pomegranate Trees Enhances Fruit Bioactive Compounds and Quality Traits at Harvest and during Postharvest Storage.

The effect of melatonin pomegranate tree treatments on fruit quality and bioactive compounds with antioxidant activity at harvest and during storage at 10 °C for 60 days was assayed in two consecutive years, 2019 and 2020. In the first year, trees were treated with 0.1, 0.3 and 0.5 mM of melatonin along the developmental fruit growth cycle, and results showed that bioactive compounds (total phenolics and total and individual anthocyanins) and antioxidant activity at harvest were higher in fruits from melatonin-treated trees than in controls. Other fruit quality parameters, such as firmness, total soluble solids and aril red colour, were also increased as a consequence of melatonin treatment. In fruit from control tress, firmness and acidity levels decreased during storage, while increases occurred on total soluble solids, leading to fruit quality reductions. These changes were delayed, and even maintenance of total acidity was observed, in fruit from melatonin-treated trees with respect to controls, resulting in a fruit shelf-life increase. Moreover, concentration of phenolics and anthocyanins and antioxidant activity were maintained at higher levels in treated than in control fruits during the whole storage period. In general, all the mentioned effects were found at the highest level with the 0.1 mM melatonin dose, and then it was selected for repeating the experiment in the second year and results of the first year were confirmed. Thus, 0.1 mM melatonin treatment could be a useful tool to enhance aril content on bioactive compounds with antioxidant activity and health beneficial effects and to improve quality traits of pomegranate fruit, at harvest and during postharvest storage.

Effect of PLA Active Packaging Containing Monoterpene-Cyclodextrin Complexes on Berries Preservation.

Blackberries and raspberries are highly perishable and fragile products, which limits their shelf life. The effect of biodegradable active packaging of blackberries and raspberries containing 2.5% and 5.0% weight (wt%) of thymol or carvacrol complexed in ß-cyclodextrins (ß-CDs), successively added to poly(lactic acid) (PLA), and melt-processed by injection molding was evaluated under stored conditions at 4 °C for 21 days, using as reference commercial clamshell and PLA package control samples. Thus, physicochemical, headspace, microbiological, and sensory quality studies were carried out in order to compare the efficacy of the different packages. Concerning weight loss, color, and total phenolic and soluble solids content, significant differences were detected when compared with commercial clamshell packaging. The results show that the PLA packages containing thymol and carvacrol complexes maintained the color, weight, and phenolic content of berries until day 21, with a score up to 45% better compared to commercial clamshell. The headspace analysis detected 101 mg L-1 (ppm) of thymol and 35 ppm of carvacrol on the first day of refrigeration; these concentrations decreased with time. This release mechanism of carvacrol and thymol into the PLA package modified the initial atmosphere composition. After 21 days of storage, the berries had 4.25 degrees of acceptance, without adverse perception of aroma or flavor for both carvacrol and thymol compounds. A general microbial inhibition was observed for yeast and molds, which increased with the concentration of monoterpene in PLA packages, and showed an inhibition of 3.5 log units for PLA packages containing thymol, and of 3 log units for those containing carvacrol. Overall results show that PLA/ß-CD-thymol 5.0% packages prolonged raspberries' and blackberries' shelf life by one more week at 4 °C, compared with commercial clamshell packaging.

Enhancing antioxidant systems by preharvest treatments with methyl jasmonate and salicylic acid leads to maintain lemon quality during cold storage.

The effects of preharvest treatments with 0.1 mM methyl jasmonate (MeJA) and 0.5 mM salicylic acid (SA) on quality parameters of lemon fruit and their relationship with antioxidant systems, gene expression and bioactive compounds at harvest and during cold storage were evaluated. Results showed that total antioxidant activity, total phenolic content and the major individual phenolics (hesperidin and eriocitrin) were always higher in treated fruit than in controls. The activity of the antioxidant enzymes catalase, peroxidase and ascorbate peroxidase was also increased at harvest by SA and MeJA treatments, especially the last enzyme, for which the expression of its codifying gene was also enhanced. In addition, treated fruit had lower weight and firmness losses, respiration rate and production of ethylene than controls. Moreover, sugars and organic acids were maintained at higher concentration in flavedo and juice as a consequence of preharvest SA and MeJA treatments, showing an effect on maintaining fruit quality properties.

Susceptibility of Blood Orange Cultivars to Chilling Injury Based on Antioxidant System and Physiological and Biochemical Responses at Different Storage Temperatures.

Susceptibility of four blood orange cultivars ('Moro', 'Tarocco', 'Sanguinello' and 'Sanguine') to chilling injury (CI) was studied. Antioxidant enzymes as well as physiological and biochemical changes were measured monthly at 2 and 5 °C plus 2 days at 20 °C for shelf life. At 2 °C, CI symptoms were higher than at 5 °C, and 'Moro' and 'Tarocco' had significantly higher CI than 'Sanguinello' and 'Sanguine'. 'Moro' and 'Tarocco' had the highest electrolyte leakage, malondialdehyde, hydrogen peroxide (H2O2) and polyphenol oxidase activity and lower phenylalanine ammonia-lyase compared with 'Sanguinello' and 'Sanguine'. The scanning electron microscopy (SEM) micrographs revealed that 'Moro' and 'Tarocco' showed severe fractures in the flavedo due to CI. 'Sanguinello' and 'Sanguine' were more tolerant to CI due to an increase of catalase, ascorbate peroxidase and superoxide dismutase, which could prevent the loss of membrane integrity and alleviate CI symptoms. Hierarchical clustering analysis (HCA) for cultivars and temperatures revealed four main clusters. The first cluster included 'Moro' and 'Tarocco' at 2 °C, and the second cluster included 'Moro' and 'Tarocco' at 5 °C. The third cluster involved 'Sanguinello' and 'Sanguine' at 2 °C, and the fourth cluster included 'Sanguinello' and 'Sanguine' at 5 °C. The order of susceptibility of cultivars to CI was 'Moro' > 'Tarocco' > 'Sanguine' > 'Sanguinello'.

Thymol Encapsulated into HP-ß-Cyclodextrin as an Alternative to Synthetic Fungicides to Induce Lemon Resistance against Sour Rot Decay.

Consumers demand the use of eco-friendly fungicides to treat fruit and vegetables and governmental authorities have unauthorized the application of chemical antifungals for the efficient control of sour rot. In the present research, the microwave irradiation (MW) method was used to encapsulate thymol into 2-hydroxylpropyl-beta-cyclodextrin (HP-ß-CD) and the effect of these HP-ß-CD on controlling sour rot in citrus fruit, caused by Geotrichum citri-aurantii, was evaluated. Amounts of 25 and 50 mM of HP-ß-CD-thymol were used, and compared with propiconazole, to control the decay of inoculated lemon fruit. The treatments were performed in curative and preventive experiments. The incidence and severity of Geotrichum citri-aurantii in 25 and 50 mM HP-ß-CD-thymol-treated fruit were reduced in both experiments. The preventive 50 mM HP-ß-CD-thymol treatment showed the best effect, reducing the sour rot, respiration rate and fruit weight loss during storage at 20 °C. HP-ß-CD-thymol increased polyphenol concentration and the activity of antioxidant enzymes, such as catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD) in lemon peel, and the highest effects were found with the 50-mM dose. In conclusion, the results show that the use of thymol encapsulated by MW into HP-ß-CD could be an effective and sustainable tool, a substitute to the synthetic fungicides, for G. citri-auriantii control in citrus fruit.

Preharvest Salicylate Treatments Enhance Antioxidant Compounds, Color and Crop Yield in Low Pigmented-Table Grape Cultivars and Preserve Quality Traits during Storage.

Previous reports reported on the effectiveness of preharvest salicylic acid (SA) treatment on increasing fruit quality properties although no information is available about acetyl salicylic acid (ASA) and methyl salicylate (MeSa) treatments. Thus, SA, ASA and MeSa were applied at 1, 5, and 10 mM in 2016 and at 1, 0.1 and 0.01 mM in 2017 to vines of 'Magenta' and 'Crimson' table grapes. Preharvest salicylate treatments at high concentration, 5 and 10 mM, delayed berry ripening and reduced crop yield, while ripening was accelerated and yield increased at lower concentrations. In addition, SA, ASA, and MeSa treatments, at 1, 0.1, and 0.01 mM, improved berry color due to increased concentration of total and individual anthocyanins, for both cultivars. Quality parameters, and especially, antioxidant bioactive compounds, such as total phenolics and total and individual anthocyanins, were found at higher levels in treated berries at harvest and during prolonged cold storage, the highest effects being found in 0.1 mM MeSa treated table grapes. Overall, it could be concluded that MeSa treatment at 0.1 mM could be the most useful tool to increase bioactive compounds with antioxidant properties in table grape and in turn, their health beneficial properties, with additional effects on increasing crop yield, accelerating on-vine ripening process and maintaining quality traits during prolonged storage.

The Effects of Salicylic Acid and Its Derivatives on Increasing Pomegranate Fruit Quality and Bioactive Compounds at Harvest and During Storage.

In the present research two experiments were performed to evaluate the effect of pre-harvest salicylic acid (SA), acetyl salicylic acid (ASA), and methyl salicylate (MeSa), applied as a foliar spray to pomegranate "Mollar de Elche," on crop yield, fruit quality parameters, and bioactive compounds at harvest and during storage. In the 2017 experiment, trees were treated with SA, ASA, and MeSa at 1, 5, and 10 mM and a higher crop yield (kg tree-1 and number of harvested fruit tree-1) and quality parameters (firmness, aril color, and individual sugars and organic acids) at harvest were obtained, as well as a higher concentration of phenolics, anthocyanins, and ascorbic acid. The best results were achieved with 10 mM dose of the three assayed compounds, which was chosen for the 2018 experiment, and results for crop yield and fruit quality attributes were confirmed. These quality traits and the concentration of phenolics, anthocyanins, and ascorbic acid were maintained at higher levels in pomegranate fruit from treated trees than in controls during prolonged storage at 10°C. In addition, the effects of salicylate treatments on increasing total and individual anthocyanin concentration in pomegranate arils led to arils with a deeper red color (Graphical Abstract) and, in turn, fruit that would be more appreciated in the international market. This fact, together with the increased crop yield, would contribute to the increased profit of this crop. Thus, pre-harvest treatment with salicylates, and especially SA at 10 mM concentration, could be a safe, natural, and new tool to improve fruit quality and its content on antioxidant compounds with health beneficial effects (namely, ascorbic acid, phenolics, and anthocyanins) at harvest and during storage.

Preharvest application of methyl jasmonate increases crop yield, fruit quality and bioactive compounds in pomegranate 'Mollar de Elche' at harvest and during postharvest storage.

BACKGROUND: Previous reports have addressed the effectiveness of postharvest methyl jasmonate (MeJA) treatments on maintaining quality properties of pomegranate fruit during storage. However, there is no literature regarding the effects of preharvest MeJA treatments on pomegranate 'Mollar de Elche' crop yield, fruit ripening, quality attributes and bioactive compounds content (at harvest or after long-term storage), which were evaluated in this research. RESULTS: Preharvest MeJA treatments (1, 5, and 10 mmol L-1 ) increased pomegranate crop yield. MeJA at 1 and 5 mmol L-1 accelerated the on-tree ripening process, while it was delayed with 10 mmol L-1 . Losses in fruit weight, firmness and organic acids during storage at 10 °C were delayed in MeJA treated fruit, leading to quality maintenance. In addition, MeJA treatments improved arils colour due to increased concentration of total and individual anthocyanins, at harvest and during storage. Total phenolic and ascorbic acid contents and total antioxidant activity [hydrophilic (H-TAA) and lipophilic (L-TAA) fractions] were also higher in arils from treated pomegranate fruits than in controls. CONCLUSION: Preharvest treatments with MeJA could be a promising tool to improve pomegranate crop yield, fruit quality and its content in bioactive compounds at harvest and during storage. The higher effects were obtained with MeJA at 5 mmol L-1 dose, which could be the selected treatment for practical application purposes. © 2019 Society of Chemical Industry.

Effect of Thymol and Carvacrol Encapsulated in Hp-Β-Cyclodextrin by Two Inclusion Methods against Geotrichum citri-aurantii.

Geotrichum citri-aurantii causes sour rot in citrus fruits and is responsible for important economic losses during storage. However, the availability of chemical fungicides for the control of this pathogen is limited. Thus, the aim of this research was to evaluate the antifungal efficacy of thymol and carvacrol encapsulated in 2-hydroxylpropyl-beta-cyclodextrin (HP-ß-CD) (prepared by the microwave irradiation method [MW] and solubility method [S]) for inhibition of G. citri-aurantii using in vitro bioassays broth (micro and macrodilutions methods) and inoculated food testing. Both encapsulated thymol and carvacrol were shown to be effective for inhibiting G. citri-aurantii growth in in vitro assays. Thymol was more effective in inhibiting G. citri-aurantii, while better encapsulation was provided by MW. HP-ß-CD-thymol encapsulated by MW (HP-ß-CD-thymol-MW) showed the lowest 50% effective dose (ED50 = 1.16 mM), minimum inhibitory concentration (MIC = 5.06 mM), and minimum fungicide concentration (MFC = 52.6 mM). HP-ß-CD-thymol-MW was found highly effective in reducing the growth rate and mycelial growth inhibition. Finally, HP-ß-CD-thymol-MW and HP-ß-CD-carvacrol-MW showed a higher persistent effect than thymol and carvacrol in their natural form in inhibiting this fungus. Therefore, HP-ß-CD-thymol-MW could be a promising alternative to synthetic fungicides for controlling G. citri-aurantii, the causal agent of citrus sour rot. PRACTICAL APPLICATION: Encapsulated thymol and carvacrol in HP-ß-Cyclodextrins are effective for controlling G. citri-aurantii in in vitro experiments. Encapsulation of thymol and carvacrol by microwave irradiation method (MW) was more effective than the solubility (S) method. Thymol was more effective than carvacrol, and the best results on G. citri-auriantii inhibition were achieved using the HP-ß-CD-thymol-MW method (which gave the lowest ED50 , MIC, and MFC).

Pre-harvest methyl jasmonate treatments increase antioxidant systems in lemon fruit without affecting yield or other fruit quality parameters.

BACKGROUND: Jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA) are hormones involved in the regulation of many processes in plants and act (when applied as a post- or pre-harvest treatment) to increase fruit bioactive compounds with antioxidant potential. However, there is no literature available regarding the effect of pre-harvest MeJA treatment on lemon fruit antioxidant systems, which was the aim of the present study. RESULTS: MeJA treatment (0.1, 0.5 and 1.0 mmol L-1 ) increased antioxidant compounds, such as phenolics, in the juice and flavedo of 'Fino' and 'Verna' lemons at harvest, with the most effective concentration being 0.1 mmol L-1 in both cultivars. In addition, catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities were also increased by MeJA treatment, with the highest increases being also found with 0.1 mmol L-1 . The increases in APX and CAT were maintained from one treatment to another during fruit development on the tree, whereas the increase on POD disappeared after 8-10 days of each treatment. For both antioxidant systems, the highest increases were found in lemon harvested at the commercial ripening stage. By contrast, crop yield, fruit ripening process and quality parameters were generally not affected by MeJA treatment. CONCLUSION: Preharvest MeJA treatment could be a useful tool for increasing antioxidant potential and the health beneficial effects of lemon fruit consumption, given the relationship between these properties and phenolic content. Moreover, the increased concentration of phenolics and the activity of antioxidant enzymes in the flavedo of MeJA treated fruit could increase lemon tolerance to chilling injury and decay during postharvest storage. © 2019 Society of Chemical Industry.

Oxalic acid preharvest treatment increases antioxidant systems and improves plum quality at harvest and during postharvest storage.

BACKGROUND: Plums are much appreciated by consumers as fresh fruit but have a limited storage life. Since reactive oxygen species (ROS) are associated with fruit ripening, an increase in ROS scavenging antioxidant systems could lead to a delay in postharvest plum ripening and in maintaining fruit quality after long cold storage. RESULTS: Results showed that crop yield (kg per tree) and fruit weight were enhanced by preharvest oxalic acid (OA) treatment of plum cultivars ('Black Splendor' and 'Royal Rosa'), although the on-tree ripening process was delayed. In addition, the ripening process during cold storage was delayed in plums from OA-treated tress, manifested by lower firmness and acidity losses and reduced ethylene production, as compared with fruits from control trees. Antioxidant compounds (phenolics, anthocyanins and carotenoids) and the activity of antioxidant enzymes were higher in plums from OA-treated trees than in controls, at harvest and during 50 days of cold storage. CONCLUSION: OA preharvest treatment could be a useful tool to maintain plum quality properties during long-term storage, by delaying the postharvest ripening process through a delay in ethylene production, with an additional effect on increasing bioactive compounds with health beneficial effects. © 2018 Society of Chemical Industry.

Preharvest treatments with salicylates enhance nutrient and antioxidant compounds in plum at harvest and after storage.

BACKGROUND: Previous reports have addressed the effectiveness of salicylic acid (SA), acetylsalicylic acid (ASA) and methylsalicylate (MeSA) postharvest treatments on maintaining quality properties during storage in several commodities. However, there is no literature regarding the effect of preharvest treatments with salicylates on plum quality attributes (at harvest or after long-term cold storage), which was evaluated in this research. RESULTS: At harvest, weight, firmness, individual organic acids, sugars, phenolics, anthocyanins and total carotenoids were found at higher levels in plums from SA-, ASA- and MeSA-treated trees than in those from controls. During storage, softening, colour changes and acidity losses were delayed in treated fruits as compared to controls. In addition, organic acids and antioxidant compounds were still found at higher levels in treated than in control plums after 40 days of storage. Results show a delay in the postharvest ripening process due to salicylate treatments, which could be attributed to their effect in delaying and decreasing ethylene production. CONCLUSION: Preharvest treatment with salicylates could be a safety, eco-friendly and new tool to improve (at harvest) and maintain (during storage) plum quality and especially its content of bioactive compounds with antioxidant properties, increasing the health effects of plum consumption. © 2017 Society of Chemical Industry.

Preharvest Application of Methyl Jasmonate as an Elicitor Improves the Yield and Phenolic Content of Artichoke.

The effects of methyl jasmonate (MeJa) treatment as an elicitor of artichoke plants [Cynara cardunculus var. scolymus (L.) Fiori] on the yield and quality attributes of artichokes, especially those related to individual phenolic content and antioxidant activity, at two harvest dates and along storage were analyzed in this research. Plants treated gave a higher yield of artichokes in comparison to control plants, with 0.55 kg more per plant. MeJa treatment also increased artichoke quality and phenolic content in the edible fraction at harvest and during storage at 2 °C for 28 days as a result of the accumulation of hydroxycinnamic acids and luteolin derivatives. In addition, antioxidant activity was enhanced by MeJa treatment and correlated with the total phenolic content. Results suggest that MeJa foliar application could be a simple and practical tool to improve the yield and phytochemical content on artichokes, with elicitation being a cheap and environmentally friendly procedure to improve the health-beneficial effects of artichoke consumption.

Enhancement of Antioxidant Systems and Storability of Two Plum Cultivars by Preharvest Treatments with Salicylates.

In this research the effect of salicylic acid (SA), acetylsalicylic acid (ASA), and methylsalicylate (MeSA) treatments, applied as a foliar spray during on-tree plum development, on fruit quality attributes, bioactive compounds, antioxidant activity, and the activity of the antioxidant enzymes at harvest and after long-term cold storage was evaluated in two plum cultivars ("Black Splendor", BS, and "Royal Rosa", RR). At harvest, plum quality parameters, such as weight, total phenolics (including anthocyanins, in BS), total carotenoids, and antioxidant activity, in both hydrophilic and lipophilic compounds were found at higher levels in plums from SA-, ASA-, and MeSA-treated trees than in those from control trees. During storage, fruit firmness, total acidity, and antioxidant compounds were at higher levels in treated, than in control, plums, which show an effect of salicylate treatments on delaying the plum postharvest ripening process. In addition, the activity of the antioxidant enzymes catalase (CAT), peroxidase (POX), superoxide dismutase (SOD), and ascorbate peroxidase (APX) were also enhanced at the time of harvest in salicylate-treated plums as compared with plums from control trees. The activity of these antioxidant enzymes was also found at higher levels in salicylate-treated plums during storage. Thus, preharvest treatment with salicylates could be a safe, eco-friendly, and new tool to improve and maintain plum quality attributes, and especially their content of antioxidant compounds, with an additional effect on delaying the postharvest ripening process through increasing the levels of antioxidant compounds and the activity of the antioxidant enzymes.

The addition of rosehip oil to Aloe gels improves their properties as postharvest coatings for maintaining quality in plum.

The effect of Aloe vera gel (AV) and Aloe arborescens gel (AA) alone or in combination with rosehip oil (RO) at 2% on ethylene production, respiration rate, quality parameters, bioactive compounds and antioxidant activity during plum postharvest storage was studied. Coated plums showed a delay in ethylene production and respiration rate at 20°C and during cold storage and subsequent shelf life, the main effect being observed for those fruits coated with AA+RO. Quality parameters such as softening, colour and maturity index was also delayed during storage by the use of the coatings, which led to a 2-fold increase in plum storability. Accumulation of bioactive compounds was also delayed although at the end of the experiment the content of bioactive compounds was higher than those found for control fruits at the estimated shelf life. The most effective coating for maintaining plum quality and bioactive compounds was AA+RO.