Effects of storage temperature and duration on chemical properties, proximate composition and selected bioactive components of pomegranate (Punica granatum L.) arils

Differential Efficacy of Storage Temperature and Postharvest Treatment on Shelf Life and Quality of Avocado Fruit (Persea americana Mill.)

Avocado fruit is a rich source of phytonutrients such as vitamins, minerals, carotenoids, carbohydrates, polyphenols and unsaturated fatty acids. However, due to its climacteric nature, fruits are highly susceptible to storage temperature, resulting in poor shelf life and reduced quality. In the present study avocado fruits (Accession CHES-HA-I/I) were stored at different low temperatures (5, 9 and 12 °C with 90-95% relative humidity, RH) to identify optimum low temperature for cold storage. In a further experiment, avocado fruits were treated with 1-methylcyclopropene (1-MCP, 500 ppb) and chitosan (0.5%) to extend the shelf life with better fruit quality. The results showed that storage temperatures had significant effect on physiological, biochemical and antioxidant activities of fruits. Lower physiological loss in weight (PLW), reduced respiration and ethylene production, and higher carbohydrates, protein and fat content were recorded in fruits stored at 9 °C as compared to 12 °C. Similarly, maximum antioxidant properties in terms of free radical scavenging activity (FRSA) and ferric reducing ability of plasma (FRAP) was found in avocado fruits stored at 9 °C. It was also noticed that chilling injury was developed in fruits stored under 5 °C. In addition, exogenous application of 1-MCP significantly reduced respiration and ethylene production rate at 9 °C and extended the shelf life up to 42 days with better fruit quality and more antioxidant activities. However, chitosan treated and control fruits had shelf life up to 28 and 21 days respectively, with minimum nutritional content. From this study it is concluded that a storage temperature of 9 °C and 1-MCP treatment significantly enhanced the shelf life of avocado fruits with better fruit quality as compared to other storage temperatures (5 and 12 °C) and postharvest treatment (chitosan).

The potential of postharvest zinc treatment for preservation of pomegranate aril quality

A short shelf life usually limits the distribution and supply of pomegranate arils. Since zinc (Zn) has an indispensable role in the nutrient integrity of our diet and is effective in suppressing pathogens, this study was done as two separate experiments of pre-harvest spraying and postharvest dipping of arils with two zinc supplements, including nano zinc oxide (nZnO) and zinc sulfate (ZnSO4). The optimized concentration of both sources was used in the experiment. The pre-harvest treatment failed to extend the shelf life of arils, and, ultimately, the arils decayed after 15 days. However, the postharvest zinc treatment significantly (P < 0.01) affected all measured indices. Also, zinc sulfate was more effective than nZnO. Zn uptake was higher in postharvest treatments because exogenous Zn was in direct contact with the aril surface. After dissolving in water, Zn ions in sulfate bind to the membrane of microorganisms and thus delay cell division and microbial growth cycle. The solubility of zinc oxide nanoparticles in water is poor. Using the ZnSO4 treatment (0.8%W/V) effectively maintained the values of titratable acidity (TA), total phenolic content (TPC), total soluble solids (TSS), anthocyanin content, and antioxidant activity. Also, this treatment significantly controlled weight loss in the arils.

Effects of organic and chemical nitrogen fertilization and postharvest treatments on the visual and nutritional quality of fresh-cut celery (Apium graveolens L.) during storage

The shelf life of horticultural commodities depends on pre- and postharvest factors, such as soil fertilization and postharvest handling. The current study aimed to evaluate fresh-cut celery's postharvest quality as affected by the rate and type (organic and chemical) of nitrogen (N) fertilizer and postharvest treatments. Celery ('Tall Utah') crop was grown in a field in Karaj, Iran. The experimental design was a randomized complete block with three replications and seven preharvest (fertilizer), and five postharvest treatments. Organic fertilizers were vermicompost (VER) and bio-organic fertilizer [farmyard and livestock manure plus Trichoderma harzianum (COM)]. Chemical fertilizers were urea (46% N) at high rate [322 kg·ha1 N (UREA_HIGH)], optimal rate [196 kg·ha-1 N (UREA_OPT)], and low rate [138 kg·ha-1 N (UREA_LOW)]; ammonium nitrate [35% N (AN)] at 196 kg·ha-1 N; and treatment without fertilization was used as a control. Postharvest treatments included plastic packaging (PP), hydrocooling (HC), blanching (B), and edible coating of psyllium seed mucilage (EC). After postharvest treatments, celery petioles were stored (0-2°C, 85%-90% RH) for 4 weeks and evaluated weekly for quality attributes. Organic fertilizers and UREA_LOW were the most effective treatments in reducing the changes in color, weight loss, titratable acidity (TA), pH, and total soluble solids (TSS) of fresh-cut celery. Organic fertilizers enhanced the vitamin C content, total phenols, and antioxidant activity in celeries. As postharvest treatments, hydrocooling, plastic packaging, and blanching maintained chroma and hue values. Blanching had the greatest effect on the L* value. Hydrocooling increased celery's TA, TSS, and vitamin C content and reduced weight loss and pH during storage. Thus, celery quality was improved when grown under low or adequate N fertilization. Hydrocooling was an effective postharvest treatment for preserving fresh-cut celery quality during storage.

Potential Anticancer Activity of Pomegranate (Punica granatum L.) Fruits of Different Color: In Vitro and In Silico Evidence

Pomegranate (PMG; Punica granatum L.) fruits possess a well-balanced nutrient/phytochemical composition, with proven adjuvant benefits in experimental cancer chemotherapy; however, such bioactivity could be affected by PMG's phenogenotype (varietal). Here, the chemical and phytochemical (UPLC-DAD-MS2) composition, antioxidant capacity and anticancer potential [in vitro (MTT assay) and in silico (foodinformatics)] of three PMG fruits of different aryl color [red (cv. Wonderful), pink (cv. Molar de Elche), and white (cv. Indian)] were evaluated. The macro/micronutrient (ascorbic acid, tocols, carotenoids), organic acid (citric/malic), and polyphenol content were changed by PMG's varietal and total antioxidant activity (ABTS, alcoholic > hexane extract) in the order of red > pink > white. However, their in vitro cytotoxicity was the same (IC50 > 200 μg.mL-1) against normal (retinal) and cancer (breast, lung, colorectal) cell lines. Sixteen major phytochemicals were tentatively identified, four of them with a high GI absorption/bioavailability score [Ellagic (pink), vanillic (red), gallic (white) acids, D-(+)-catechin (white)] and three of them with multiple molecular targets [Ellagic (52) > vanillic (32) > gallic (23)] associated with anticancer (at initiation and promotion stages) activity. The anticancer potential of the PMG fruit is phenogenotype-specific, although it could be more effective in nutraceutical formulations (concentrates).

Application of Aloe vera Gel Coating Enriched with Cinnamon and Rosehip Oils to Maintain Quality and Extend Shelf Life of Pomegranate Arils

A completely randomized design was applied on pomegranate arils for several post-harvest treatments before the packaging in polypropylene boxes for 15 days at (5 ± 1 °C, 95 ± 2% RH): control (untreated), Aloe vera gel (10% or 20%), 10% Aloe vera + rosehip oil (0.25% or 0.50%), 20% Aloe vera + rosehip oil (0.25% or 0.50%), 10% Aloe vera + cinnamon oil (0.25% or 0.50%), and 20% Aloe vera + cinnamon oil (0.25% or 0.50%). Aloe vera in combination with cinnamon oil resulted in an enhanced shelf life (15 d) compared to the uncoated arils (control). The Aloe vera + cinnamon oil coating led to the retention of total phenolics, anthocyanin, ascorbic acid, and antioxidant activity in context to the quality attributes. Moreover, this coating showed minimal change in the color, total soluble solids, titratable acidity, firmness, delayed ethylene production, respiration rate, and physiological weight loss. Also, A. vera + cinnamon oil coatings significantly (p < 0.05) inhibited the total counts of mesophilic aerobics, coliforms, and yeast and mold. Organoleptic attributes, including color, flavor, aroma, texture, and purchase acceptability were higher for the arils that were treated with 10% A. vera + 0.25% cinnamon oil; thus, this highly economical and easily available coating material can be formulated and used commercially to extend the shelf life and enhance the profit of the producers and/or processors.

Chitosan-Cinnamon Oil Coating Maintains Quality and Extends Shelf Life of Ready-to-Use Pomegranate Arils under Low-Temperature Storage

Different formulations of chitosan (1%, 2%, or 3%) with the incorporation of cinnamon oil (0.25% or 0.50%) were prepared for the preservation of pomegranate aril cv. Bhagwa. Six combinations of chitosan-cinnamon oil formulations along with one control (untreated) were applied to the freshly extracted arils using the dipping application method. All treatments were found to be effective in enhancing the shelf life, improving the postharvest characteristics, and reducing microbial populations on pomegranate arils during a 15-day storage period at 4 ± 1°C. The treated pomegranate arils exhibited excellent resistance to microbial decay, moisture loss, respiration rate, preservation of phenolics, flavonoids, and antioxidants activity, among other characteristics. Chitosan 2% + cinnamon oil 0.25% edible coating has a high potential to enhance the storage life and biochemical properties and reduce the microbial population of arils. This treatment recorded a higher total phenolic content (18%) and antioxidant activity (16%) than the control sample, respectively, at the end of storage. In addition, the treatment also helped to decrease the microbial activity by 45% compared to the control sample. The present investigation proposed an alternative method to prolong the shelf life of pomegranate arils during the 15 days of storage.

Non-destructive Evaluation of the Quality Characteristics of Pomegranate Kernel Oil by Fourier Transform Near-Infrared and Mid-Infrared Spectroscopy

The pomegranate kernel oil has gained global awareness due to the health benefits associated with its consumption; these benefits have been attributed to its unique fatty acid composition. For quality control of edible fats and oils, various analytical and calorimetric methods are often used, however, these methods are expensive, labor-intensive, and often require specialized sample preparation making them impractical on a commercial scale. Therefore, objective, rapid, accurate, and cost-effective methods are required. In this study, Fourier transformed near-infrared (FT-NIR) and mid-infrared (FT-MIR) spectroscopy as a fast non-destructive technique was investigated and compared to qualitatively and quantitatively predict the quality attributes of pomegranate kernel oil (cv. Wonderful, Acco, Herskawitz). For qualitative analysis, principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) was applied. Based on OPLS-DA, FT-MIR spectroscopy resulted in 100% discrimination between oil samples extracted from different cultivars. For quantitative analysis, partial least squares regression was used for model development over the NIR region of 7,498-940 and 6,102-5,774 cm-1 and provided the best prediction statistics for total carotenoid content (R 2, coefficient of determination; RMSEP, root mean square error of prediction; RPD, residual prediction deviation; R 2 = 0.843, RMSEP = 0.019 g β-carotene/kg, RPD = 2.28). In the MIR region of 3,996-1,118 cm-1, models developed using FT-MIR spectroscopy gave the best prediction statistics for peroxide value (R 2 = 0.919, RMSEP = 1.05 meq, RPD = 3.54) and refractive index (R 2 = 0.912, RMSEP = 0.0002, RPD = 3.43). These results demonstrate the potential of infrared spectroscopy combined with chemometric analysis for rapid screening of pomegranate oil quality attributes.

Effects of Argon-Based and Nitrogen-Based Modified Atmosphere Packaging Technology on the Quality of Pomegranate (Punica granatum L. cv. Wonderful) Arils

Ready-to-eat pomegranate arils are considered a “functional food” for their health benefits and have desirable sensory characteristics, which have caused an increasing interest by the consumers for this product. The preparation process of ready-to-eat fruit products can cause severe injuries and worsen their quality and shelf life significantly. Modified atmosphere packaging (MAP) has been used broadly in the last years to maintain the quality of processed fruits and showed optimal results, in spite of the possible problems caused by the depletion of O₂ and corresponding accumulation of CO₂ in the package. This study was conducted to evaluate the effects of different MAP treatments, based on nitrogen or alternatively on a noble gas, argon, in combination with refrigerated storage (0, 4, 8, 12, and 16 days at 4 ± 1 °C and 90 ± 5% RH) on the qualitative parameters of pomegranate arils with the aim to prolong their post-harvest life maintaining the original quality. The argon-based MAP treatment (MAPAr) was the one that provided the best results, assuring a limited loss of weight and juice content. The use of noble gas allowed to maintain a high sugar/acid ratio until 16 days from packaging. Sensory analysis on all MAP treated arils and, on the juice, obtained from them were carried out, and judges showed a preference for MAPAr treated arils and juice until day 12 from packaging.

Ultrasonic potential in maintaining the quality and reducing the microbial load of minimally processed pomegranate

Difficulty of Pomegranate fruit peeling and arils separation are the main motivations of progressive ready-to-eat pomegranate fresh arils industry. Also, extracted pomegranate arils are highly perishable due to water loss and microbial contamination expose. The aim of the current work was then to evaluate the effect of ultrasound for 15 and 30 min on maintenance of bioactive compounds and microbial load reduction of pomegranate arils cv. Rabbab. Treated arils were kept at 5 °C and analyzed during 15 days of storage. The most and least weight loss of arils obtained in control and 30 min treated samples, respectively. After 12 days of storage, all samples were decayed except those treated for 15 and 30 min. The ultrasound treatment significantly prevented degradation of anthocyanin and ascorbic acid compounds. Total phenol and antioxidant activity decreased during storage. At the end of storage, the most total phenol content (3898.6 mg GAE L-1) was found in arils treated for 30 min whereas the most anthocyanin (91.93 mg L-1), total antioxidant activity (82.65%), and ascorbic acid (2.53 mg L-1) were found in arils treated for 15 min. Ultrasound treated arils had lower microbial load (total mesophilic bacteria in control and 30-min treated samples) in each stage during storage. At the end of storage, the microbial load in treated and control arils was 0.7 and 0.2 Log CFU g-1, respectively). Overall, ultrasound treatment effectively reduced weight loss and preserved bioactive compounds during storage.

Selenium and silica nanostructure-based recovery of strawberry plants subjected to drought stress

Drought is an important environmental stress that has negative effects on plant growth leading to a reduction in yield. In this study, the positive role of nanoparticles of SiO₂, Se, and Se/SiO₂ (SiO₂-NPs, Se-NPs and Se/SiO₂-NPs) has been investigated in modulating negative effects of drought on the growth and yield of strawberry plants. Spraying of solutions containing nanoparticles of SiO₂, Se, and Se/SiO₂ (50 and 100 mg L⁻¹) improved the growth and yield parameters of strawberry plants grown under normal and drought stress conditions (30, 60, and 100%FC). Plants treated with Se/SiO₂ (100 mg L⁻¹) preserved more of their photosynthetic pigments compared with other treated plants and presented higher levels of key osmolytes such as carbohydrate and proline. This treatment also increased relative water content (RWC), membrane stability index (MSI) and water use efficiency (WUE). In addition, exogenous spraying of Se/SiO₂ increased drought tolerance through increasing the activity of antioxidant enzymes including catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and superoxide dismutase (SOD) as well as decreasing lipid peroxidation and hydrogen peroxide (H₂O₂) content. Increase in biochemical parameters of fruits such as anthocyanin, total phenolic compounds (TPC), vitamin C and antioxidant activity (DPPH) in strawberry plants treated with Se/SiO₂ under drought stress revealed the positive effects of these nanoparticles in improving fruit quality and nutritional value. In general, our results supported the positive effect of the application of selenium and silicon nanoparticles, especially the absolute role of Se/SiO₂ (100 mg L⁻¹), on the management of harmful effects of soil drought stress not only in strawberry plants, but also in other agricultural crops.

Maintenance of quality and bioactive compounds of cold stored pomegranate (Punica granatum L.) fruit by organic acids treatment

Pomegranate is a subtropical and chilling sensitive fruit. In this study, the effects of malic acid (50 and 100 mM) and oxalic acid (5 and 10 mM) on quality properties of pomegranate during cold storage (2 ℃) were investigated. The lowest weight loss was observed in fruit treated with 50 mM malic acid. Malic acid had positive effects on color parameters (L*, a*, and b*) of pomegranate at low temperature. Organic acid treatments reduced chilling injury, malondialdehyde, and hydrogen peroxide and increased catalase activity. The lowest activity of polyphenol oxidase and peroxidase was observed in 5 mM oxalic acid-treated fruit. On the other hand, fruit treated with 50 mM malic acid showed the maximum ascorbic acid and citric acid content. The most antioxidant activity was found in fruit treated with 5 mM oxalic acid and 50 mM malic acid. Also, all treatments except 10 mM oxalic acid and 100 mM malic acid resulted in higher titratable acidity than control fruit. Overall, 50 mM malic acid and 5 mM oxalic acid were the most effective for preserving the quality of pomegranate fruit at low temperature.

Comparison the effect of putrescine application on postharvest quality of Pyrus communis cv. "Shah-Miveh" and "Spadona"

Role of putrescine for extending storage life of pear cv. "Shah-Miveh" and "Spadona" was evaluated. The trees were sprayed by various concentrations of putrescine (0.5, 1, and 2 mM) and distilled water "control." After harvest, all samples were stored at 0 ± 1°C, 80%-85% RH for 21 weeks. Thereafter, some physico-chemical attributes were measured initially and after each storage period 7, 14, and 21 weeks. Putrescine at 1 and 2 mM reduced fruit softening, weight loss, color changes (L*, hue angle), fungal infection as well as retarded the degradation of total soluble solids, titratable acidity, ascorbic acid, total phenol (TP), and total antioxidant activity (TAA). However, fruit softening, weight loss, and hue angle rates were slower in "Shah-Miveh" to "Spadona." Moreover, at the end of storage, "Shah-Miveh" demonstrated more TP and TAA in compare to "Spadona." Thus, putrescine application at higher values may be an effective tool to prolong pear postharvest life during storage.

Effects of postharvest treatments with chitosan and putrescine to maintain quality and extend shelf-life of two banana cultivars

Chitosan (1.0% and 2.0%) and putrescine (1.0 and 2.0 mmol/L) treatments were used to investigate the effects of these compounds on the postharvest quality and shelf-life of two banana cultivars, "Native" and "Cavendish." Fruits were stored at 15 ± 2°C and a relative humidity of 85%-90% during a 20-day period. In the controls, increases in weight loss, microbial population, total soluble solids, and ethylene production and decreases in firmness, ascorbic acid contents, and fruit lightness occurred gradually during storage. All these changes were delayed significantly after treatments with chitosan and putrescine. Application of putrescine and chitosan also caused small increases in phenolic compound contents and antioxidant activity at the end of the storage period. Results obtained suggest that a treatment with 1% chitosan is effective in improving the postharvest quality and shelf-life of banana, and open the possibility that lower concentrations of chitosan may be also effective.

Flaxseed gum in combination with lemongrass essential oil as an effective edible coating for ready-to-eat pomegranate arils

Flaxseed gum (FSG) in combination with lemongrass essential oil (LGEO) was investigated for coating of ready-to-eat pomegranate arils. FSG was used at 0.3% and 0.6% concentrations and with both concentrations LGEO was incorporated at levels of 0ppm, 200ppm, 500ppm and 800ppm. Changes in headspace gases, physicochemical, microbiological and sensory attributes of pomegranate arils stored at 5°C were studied on different days of analysis during the 12day storage period. Coatings containing LGEO were effective in reducing total plate count and yeast and mold populations. Increasing LGEO concentrations in the coatings resulted in more decline in microbial populations. Reduced weight loss occurred in coated samples as compared to uncoated (control) sample. Coated samples showed a gradual decrease in ripening index in contrast with control where a significantly higher decline was observed. Total soluble solids, pH and titratable acidity significantly varied over the storage period. Color change (ΔE) for control increased steeply over the storage time in comparison to coated samples. Furthermore, chroma decreased while as hue angle increased over time.