Ethylene Production Rate Research Articles

Postharvest treatment of navel oranges with fluroxypyr, 2-methyl-4-chlorophenoxyacetic acids, and 2,4-dichlorophenoxyacetic maintains physiological quality during ambient storage

Two batches of Green mature Navel oranges with calyxes attached were obtained from a farmer from Juaben Municipality in the Ashanti region of Ghana and were dipped for 2 minutes with fluroxypyr, and 2-methyl-4-chlorophenoxyacetic acid (MCPA), were assessed against the commercial 2,4-D at 0.1 and 0.2 mmol L-1 stored under ambient conditions (24±2 °C and 55-60% RH) for 4 weeks. The results showed that pre-storage dipping with fluroxypyr was the most effective in suppressing endogenous ethylene production and respiration rate, reduced calyx changes, and fruit rot, and retained fruit sensory attributes compared with MCPA 2,4-D, or untreated fruit at the end of storage life of four weeks. The effect of 2,4-D and MCPA on fruit rot, calyx browning, abscission, and fruit internal quality, was similar; which was not significantly different during storage. Dipping fruit with 0.1 mmol L-1 fluroxypyr was more effective in maintaining the quality of oranges and could be a substitute for current commercial 2,4-D.

Effects of cinnamic acid on the root growth of cucumber (cucumis sativus l.) and figleaf ground (cucurbita ficifolia bouché) seedlings

Effect of cinnamic acid (CA) on growth and endogenous hormone content in the roots of cucumber and figleaf gourd seedlings were studied and explained the reason why figleaf gourd was better in resisting CA stress than cucumber using their seedlings as experimental materials. The effect of CA at different concentrations (0, 0.05, 0.10, 0.15, 0.20 and 0.25 mmol/l) was analysed on primary root elongation, total root elongation, average diameter of total roots, total root volume, and total root tips as well as the effects of 0 and 0.25 mmol/l CA on root growth, root density, root hair growth rate, indole acetic acid (IAA) content and ethylene (ET) production rate. The results showed that CA stress decreased the primary root elongation, total root elongation, total root tips, Grade III root and root hair growth rates of both plants. The inhibiting effect of CA was stronger on cucumber than figleaf gourd. Besides, CA stress increased their average diameters of total roots and root hair densities. The increase in the average diameter of total roots of cucumber was larger than that of figleaf gourd while its increase in root hair density was far lower. Apart from that, 0.25 mmol/l CA stress increased the IAA contents and ET production rates in both kinds of roots. The increase in IAA content in cucumber root was 16% higher than in figleaf gourd. However, the increase in the ET production rate of cucumber root was 51% lower than figleaf gourd root. In conclusion, higher concentration IAA could inhibit root growth. Under CA stress, the increase in the IAA content in figleaf gourd root was lower than that in cucumber root, indicating that CA exerted a weaker inhibiting influence on figleaf gourd. Besides, higher ET production rate contributed to the increase in root hair density. Under CA stress, figleaf gourd root had a higher ET production rate than cucumber root, thus having more root hairs. Bangladesh J. Bot. 53(3): 703-710, 2024 (September) Special

Extending Raspberry Shelf Life and Maintaining Postharvest Quality with CO2 Atmospheres

Raspberry (Rubus idaeus L.) fruit are known for their extremely short shelf life. Decay, leakiness, and loss of firmness are the most common limiting factors contributing to their short storage life. However, storage in elevated CO2 and reduced O2 atmospheres can delay senescence in fruit by reducing softening, respiration and ethylene production rates, and pathogen growth. In this study, raspberries were exposed to four different CO2 atmospheres—15 kPa CO2 and 6 kPa O2 (15 kPa); 8 kPa CO2 and 13 kPa O2 (8 kPa); 5 kPa CO2 and 16 kPa O2 (5 kPa); or 0.03 kPa CO2 and 21 kPa O2 (0.03 kPa)—and were evaluated for their postharvest quality periodically during two weeks of storage in 2020 and 2021. Raspberry fruits kept in a 15 kPa CO2 atmosphere followed by 8 kPa CO2 had higher firmness, brighter red color, and the least fungal decay or leakiness. In all atmospheres, the total anthocyanin content increased over time, although the rate of increase was slowed by high CO2. The raspberries’ visual attributes deteriorated over time in all atmospheres, but high CO2 atmospheres slowed the rate of deterioration. After five days, the quality of air-stored raspberries was significantly degraded, while the raspberries stored in elevated CO2 maintained good quality for up to ten days.

Deciphering the Effects of Different Calcium Sources on the Plant Growth, Yield, Quality, and Postharvest Quality Parameters of ‘Tomato’

Tomatoes are one of the most important vegetables in every home, especially in South Asian countries, used as a vegetable, ketchup, and condiment in many kitchen recipes. It is a good source of calcium, potassium, folate, vitamin A, vitamin K, and lycopene, which are beneficial for the human body and protect it against different diseases. Nutrient management is a key factor for the best quality production of tomato fruit. The present study was conducted to compare the efficiency of different calcium salts (calcium sulphate, calcium carbonate, calcium nitrate, and calcium chloride) in improving the growth, yield, and other quality-related parameters of tomatoes. A single field experiment was conducted and laid out according to the Randomized Complete Block Design (RCBD) with a single factor in the field and a Complete Randomized Design (CRD)) for postharvest fruit storage. The results obtained from this experiment suggest that plants treated with 2% calcium chloride solution exhibited the greatest plant height (85.27 cm), number of leaves (221), yield per plant (2.3 kg), ascorbate peroxidase (290.75 m mol s−1 kg−1), superoxide dismutase (7.13 m mol s−1 kg−1), catalase (18.74 m mol s−1 kg−1), total phenolics (2.44 mg g−1), and β carotene (0.48 µg g−1). During postharvest storage, the maximum shelf life (18 days), minimum disease incidence (4.78%), weight loss (6.61%), and ethylene production (119.6 µL C2H4 kg−1h−1) rate were also observed in calcium-treated fruits.

Aminoethoxyvinylglicine and 1-Methylcyclopropene: Effects on Preharvest Drop, Fruit Maturity, Quality, and Associated Gene Expression of 'Honeycrisp' Apples in the US Mid-Atlantic.

Preharvest fruit drop is one of the main challenges in apple production as it can lead to extensive crop losses in commercially important cultivars including 'Honeycrisp'. Plant growth regulators, such as aminoethoxyvinylglicine (AVG) and 1-methylcyclopropene (1-MCP), which hinder ethylene biosynthesis and perception, respectively, can control preharvest fruit drop, but an assessment of their effects in 'Honeycrisp' fruit grown under US mid-Atlantic conditions is lacking. In this study, we evaluated the effects of AVG (130 mg a.i. L-1) and 1-MCP (150 mg a.i. L-1) on preharvest fruit drop, ethylene production, fruit physicochemical parameters, skin color, and transcript accumulation of ethylene and anthocyanin-related genes in 'Honeycrisp' apples throughout on-the-tree ripening. We showed that both AVG and 1-MCP significantly minimized preharvest fruit drop with respect to the control fruit. Additionally, AVG was the most effective in decreasing ethylene production, downregulating ethylene biosynthesis and perception-related gene expression, and delaying fruit maturity. Nevertheless, AVG negatively impacted apple red skin color and exhibited the lowest expression of anthocyanin-biosynthesis-related genes, only allowing apples to reach the minimum required 50% blush at the last ripening stage. Conversely, 1-MCP-treated fruit displayed an intermediate behavior between AVG-treated and control fruit, decreasing ethylene production rates and the associated gene expression as well as delaying fruit maturity when compared to the control fruit. Remarkably, 1-MCP treatment did not sacrifice red skin color development or anthocyanin-biosynthesis-related gene expression, thus exhibiting > 50% blush one week earlier than AVG.

Sustainable active packaging developed using starch-based foam incorporating 1-Methylcyclopropene@α-Cyclodextrin

The preservation of fruit freshness during long-distance transportation frequently faces significant challenges, especially a high risk of spoilage. 1-Methylcyclopropene (1-MCP), an effective ethylene inhibitor, is widely used to slow down fruit ripening and maintain freshness. However, achieving a controllable release of 1-MCP is challenging, and traditional carrier materials such as paper, chitosan films, and microcapsules have proven unsatisfactory. Here, we introduced an innovative sustainable packaging featuring a “sandwich” structure based on starch-based foam sheets. The hydrophilic properties and porous structure of the foam ensure the controllable and slow release of 1-MCP. Additionally, its mechanical durability provides a cushioning role to minimize physical damage to fruits during transport process. This method achieves a significant reduction in ethylene production and respiration rates by up to 60.49 % and 57.50 % respectively, leading to an extension of the shelf life of climacteric fruits by 5–10 days. The novel active packaging not only effectively prolongs the shelf life and improves the quality of fruit but is also economical and environmentally friendly due to its biodegradable starch-based composition.

An Efficient Trifunctional Spinel-Based Electrode for Oxygen Reduction/Evolution Reactions and Nonoxidative Ethane Dehydrogenation on Protonic Ceramic Electrochemical Cells.

Protonic ceramic electrochemical cells (PCECs) have received considerable attention as they can directly generate electricity and/or produce chemicals. Development of the electrodes with the trifunctionalities of oxygen reduction/evolution and nonoxidative ethane dehydrogenation is yet challenging. Here these findings are reported in the design of trifunctional electrodes for PCECs with a detailed composition of Mn0.9Cs0.1Co2O4-δ (MCCO) and Co3O4 (CO) (MCCO-CO, 8:2 mass ratio). At 600°C, the MCCO-CO electrode exhibits a low area-specific resistance of 0.382 Ω cm2 and reasonable stability for ≈105h with no obvious degradation. The single cell with the MCCO-CO electrode shows an encouraging peak power density of 1.73W cm-2 in the fuel cell (FC) mode and a current density of -3.93 A cm-2 at 1.3V in the electrolysis cell (EC) mode at 700°C. Moreover, the MCCO-CO cell displays promising operational stability in FC mode (223h), EC mode (209h), and reversible cycling stability (52 cycles, 208h) at 650°C. The MCCO-CO single cell shows an encouraging ethaneconversion to ethylene (with a conversion of 40.3% and selectivity of 94%) and excellent H2 production rates of 4.65mL min-1 cm-2 at 1.5V and 700°C, respectively, with reasonable Faradaic efficiencies.

Fabrication and characterization of a chitosan/cyclodextrin/TiO2-NPs composite for preservation of avocados.

In this study, a TiO2 material with nanoparticle size of about 10-20 nm, surface area of 109 m2 g-1 was synthesized using the microwave-assisted hydrothermal method. The chitosan/TiO2 film combined with cyclodextrin (chitosan-cyclodextrin/TiO2, CS-CD/TiO2NPs) helps significantly improve the mechanical properties and enhance the antibacterial activity of the polymer film. Furthermore, the content of TiO2 nanoparticles in CS-CD/TiO2NPs also affects the tensile strength, antibacterial activity, ripening rate, ethylene production rate, and water vapor permeability during food preservation of the CS-CD film that has been studied. The CS-CD/TiO2NPs film is effective against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aereus) reaching over 99.5% after 15 min of contact. The preservation ability of avocados coated with CS-CD/TiO2NPs was evaluated through some physiological parameters of the avocados, such as sensory evaluation, weight loss, and hardness. The results show that the use of CS-CD/TiO2NPs films extends the preservation time of avocados up to 7 days under conditions of 30 °C and 80% relative humidity.

The Shelf Life of Yellow Passion Fruit with an Edible Biocomposite Coating Based on Chitosan, Graphene Oxide Nanoparticles, and Beeswax

Yellow or sour passion fruit is a climacteric fruit with a high rate of respiration and ethylene production, and postharvest technology is needed to extend its shelf life. This study investigated the properties of a biocomposite film with chitosan (CH) incorporated with beeswax (BW) and graphene oxide (GO) nanoparticles for use as an edible coating to extend the shelf life of yellow passion fruit at 22 °C and 70% RH for eight days. CH films associated with BW showed lower water vapor permeability (WVP) than films with CH alone. However, adding GO to the CH + BW biopolymer matrix improved the WVP, decreased the solubility (12.8%), and increased the opacity of the film by 9% compared to those of the CH film. Fruits coated with CH + BW or CH + BW + GO exhibited a reduction in respiration rate, a slower ripening process by approximately 3 days, and a significant decrease in weight loss. This also resulted in a higher soluble solids content and increased antioxidative capacity of the pulp. The incorporation of GO into the CH + BW matrix resulted in a more pronounced delay of fruit ripening, as evidenced by the lower depigmentation of the peel at eight days, with a lightness approximately 10.7% lower at 54.92, a chroma value 16.5% lower at 49.33, a hue angle 7.2% higher at 92.56, a soluble solid (SS) content 16.7% higher at 11.32°Brix, and an acidity 31.9% higher at 4.18% compared to the control. Furthermore, the biopolymer packaging led to a higher consumer acceptance score for the fruit.

Application and toxicological study of polyvinyl acetate (PVAc) coating on lemon (Citrus limon L.) fruit to extend the shelf life

The objective of the present study is to examine how different concentrations of polyvinyl acetate (PVAc) coating (2.5%, 5.0%, 7.5%, 10.0%, and 12.5%) affect the quality of lemons during storage at (27 ± 2)°C, with the aim of extending their shelf life. Lemons are known for being a rich source of citric acid, ascorbic acid, and dietary fiber. During the study, the coated lemons were regularly assessed for various parameters such as weight loss, respiration rate, firmness, decay incidence, total soluble solids, pH, ascorbic acid, and juice content. The results revealed that lemons coated with 10.0% and 12.5% concentrations of PVAc exhibited a significant (P < 0.05) impact in reducing the respiration rate, ethylene production rate, weight loss, and maintaining firmness compared to the control sample. Furthermore, the study also investigated the potential acute toxicological and histological effects of the PVAc (12.5%) coated sample on mice. The results indicated that there were no harmful or lethal effects observed in the experimental mice. Therefore, the PVAc coating at concentrations of 10.0% and 12.5% proves to be beneficial in preserving the natural color of lemons and minimizing senescence during storage at (27 ± 2)°C.

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, 500ppb) 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 42days with better fruit quality and more antioxidant activities. However, chitosan treated and control fruits had shelf life up to 28 and 21days 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).

Avocado (Persea americana Mill.) Postharvest Organic Nutritional Conservation Employing Carboxyl Methylcellulose (CMC) Manufactured Out from Moringa Plant

The research concluded that the use of extracts of moringa leaves and moringa seed as an edible coating might help to preserve the shelf life and also the quality of Avocado. The cultivars that were focused on during this research were “Hass” and “Gem”. It may also reduce the risk of infection and inflammation in these cultivars. Methanolic and ethanolic moringa extracts were also examined for their antifungal properties. Shortly, 1% Carboxyl methylcellulose which is shown as CMC and 2% MLE which is Moringa Leaf Extract or MSE which is moringa seed extract, were combined. The fruit was either coated with either (MLE + CMC) or that of (MSE + CMC) and then it was kept at a temperature of 5.5°C and 95% relative humidity (RH) for a period of 21 days. The fruit was kept at ambient temperatures i.e. 21°C and 60% RH, after being refrigerated to approximate retailing conditions. Fruit firmness and postharvest quality indicators including ethylene production and respiration rate were analyzed. In relation to potato dextrose agarose which is shortened as PDA, both coatings were also evaluated for their effectiveness against the fungus which may spoil the fruit quality during postharvest opperations. Compared to uncoated fruit, the coated fruit was noticed to have less mass loss. Respiration rates were also observed to be decreased along with Ethylene production, in a contrast to the uncoated fruit. A. alternata and C. gloeosporioides were both inhibited by ethanol leaf extract by 43.60% and 42.90%, respectively. All pathogens exposed to coverings had damaged hyphal structures, while uncoated fruit had healthy hyphal structures. Stronger antibacterial activity was observed in ethanolic moringa leaf extracts as compared to the extracts that were derived from methanol. The outcomes of this research showed that carboxyl methylcellulose CMC containing moringa extract reduces illnesses in fruit. Throughout the postharvest supply chain, it also maintains the general quality of avocados. The shelf life of the avocado was remarkably increased. The avocado sector may eventually commercialize the moringa extracts combined with carboxyl methylcellulose, as a new organic edible covering.

Nano-TiO2 enhanced fruit storage chambers: unveiling the potential for prolonging banana shelf life

ABSTRACT This manuscript focuses on the development of Fruit Storage Chamber (FSC) equipped with nano-TiO2 and its modular prototype to improve the value of bamboo-based FSC by its photocatalytic and feasibility aspects. Its effects on fruit shelf life and ripening-related gene expression were studied. Cavendish bananas were stored in FSC equipped with nano-TiO2 and modular FSC for treatments. Relative expression level of ethylene biosynthesis-related (MaACS1, MaACO1) and polyphenol oxidase (MaPPO4, MaPPO5) genes were examined. The dynamics of ripening variables throughout the storage period were illustrated in regression lines, followed with hypothesis testing. Banana quantity showed no significant changes upon storage in FSC equipped with nano-TiO2. Physical appearance indicated a ripening delay of up to two days on nano-TiO2 treatments compared to control. Ethylene production rate and ethylene related gene expression were not significantly altered. Browning index was more maintained in nano-TiO2 treated samples, supported by the observation of slower increase of MaPPO4 and MaPPO5 relative expressions compared to control. The findings highlight the suppression of fruit ripening related gene expression and the maintenance of fruit quality in treated samples compared to control, indicating the potential use of nano-TiO2 to prolong banana shelf life.

Effect of ethylene production by four pathogenic fungi on the postharvest diseases of green pepper (Capsicum annuum L.)

Ethylene produced by plants generally induces ripening and promotes decay, whereas the effect of ethylene produced by pathogens on plant diseases remains unclear. In this study, four ethylene-producing fungi including Alternaria alternata (A. alternata, Aa), Fusarium verticilliodes (F. verticillioides, Fv), Fusarium fujikuroi 1 (F. fujikuroi 1, Ff-1) and Fusarium fujikuroi 2 (F. fujikuroi 2, Ff-2) were severally inoculated in potato dextrose broth (PDB) media and postharvest green peppers, the ethylene production rates, disease indexes and chlorophyll fluorescence parameters were determined. The results showed that Ff-2 and Fv in the PDB media had the highest and almost the same ethylene production rates. After inoculation with green peppers, Ff-2 treated group still exhibited the highest ethylene production rate, whereas Aa treated group had a weak promotion effect on ethylene production. Moreover, the ethylene production rate of green peppers with mechanical injury was twice that without mechanical injury, and the ethylene production rates of green peppers treated with Aa, Ff-1, Ff-2 and Fv were 1.2, 2.6, 3.8 and 2.8 folds than those of green peppers without treatment, respectively. These results indicated that pathogen infection stimulated the synthesis of ethylene in green peppers. Correlation analysis indicated that the degreening of Fusarium-infected green pepper was significantly positively correlated with the ethylene production rate of green pepper, whereas the disease spot of Aa-infected green pepper had a significant positive correlations with the ethylene production rate of green peppers. Chlorophyll fluorescence results showed that the green peppers already suffered from severe disease after being infected with fungi for 4 days, and Fusarium infection caused early and serious stress, while the harm caused by A. alternata was relatively mild at the early stage. Our results clearly showed that α-keto-γ-methylthiobutyric acid (KMBA)-mediated ethylene synthesis was the major ethylene synthesis pathway in the four postharvest pathogenic fungi. All the results obtained suggested that ethylene might be the main infection factor of Fusarium spp. in green peppers. For pathogenic fungi, stimulating green peppers to produce high level of ethylene played a key role in the degreening of green peppers.

Biochemical dynamics during postharvest: Highlighting the interplay of stress during storage and maturation of fresh produce.

The lifecycle of fresh produce involves a sequence of biochemical events during their ontology, and these events are particularly significant for climacteric fruits. A high demand during ripening is observed in these plant products, which is reflected in a high rate of respiration and ethylene production. Increased respiratory demand triggers the activation of secondary pathways such as alternate oxidase, which do not experience critical increases in energy consumption in non-climacteric fruit. In addition, biochemical events produced by external factors lead to compensatory responses in fresh produce to counteract the oxidative stress caused by the former. The dynamics of these responses are accompanied by signaling, where reactive oxygen species play a pivotal role in fresh product cell perception. This review aims to describe the protection mechanisms of fresh produce against environmental challenges and how controlled doses of abiotic stressors can be used to improve quality and prolong their shelf-life through the interaction of stress and defense mechanisms.

Enhancing postharvest quality and extending storage life of Booth 7 avocado (Persea americana Mill.) fruit through sodium nitroprusside (SNP) application during low-temperature storage

Postharvest quality plays a crucial role in marketability, consumer acceptability, and shelf life of avocados. This study investigates the efficacy of nitric oxide (NO) on postharvest physiology and quality of Booth 7 avocados treated with different concentrations of sodium nitroprusside (SNP) - a nitric oxide-releasing compound. Booth 7 avocados were immersed in SNP solutions (0.5 mM, 1.0 mM, and 1.5 mM), while the control fruit was immersed in distilled water for 15 min. After treatment, the fruit was stored at a temperature (T) of 8 ± 1 °C and relative humidity (RH) of 90 ± 5% for 35 days, during which the control fruit exhibited complete deterioration. The results revealed that Booth 7 avocados treated with 1.5 mM SNP concentration exhibited delayed quality changes during storage, reduced ethylene production and respiration rate, reduced alterations in soluble solids and acid content of the fruit flesh, as well as delayed changes in flesh and peel color. Additionally, the activity of total phenolic compounds (TPC), polygalacturonase (PG), and polyphenol oxidase (PPO) enzymes increased significantly, while the activity of the pectin methyl esterase (PME) enzyme was reduced. In conclusion, SNP treatment improved the quality and can be utilized as a potential postharvest preservative for Booth 7 avocados. For producers and distributors, the use of SNP in avocado postharvest management offers the potential to extend shelf life without compromising fruit quality.

Effects of 1-methylcyclopropene on skin greasiness and quality of 'Yuluxiang’ pear during storage at 20°C

During storage at 20°C, specific pear cultivars may exhibit a greasy texture and decline in quality due to fruit senescence. Among these varieties, 'Yuluxiang’ is particularly susceptible to peel greasiness, resulting in significant economic losses. Therefore, there is an urgent need for a preservative that can effectively inhibit the development of greasiness. Previous studies have demonstrated the efficacy of 1-methylcyclopropene (1-MCP) in extending the storage period of fruits. We hypothesize that it may also influence the occurrence of postharvest peel greasiness in the 'Yuluxiang’ pears. In this study, we treated 'Yuluxiang’ pears with 1-MCP. We stored them at 20°C while analyzing the composition and morphology of the surface waxes, recording enzyme activities related to wax synthesis, and measuring indicators associated with fruit storage quality and physiological characteristics. The results demonstrate that prolonged storage at 20°C leads to a rapid increase in skin greasiness, consistent with the observed elevations in L*, greasiness score, and the content of total wax and greasy wax components. Moreover, there were indications that cuticular waxes underwent melting, resulting in the formation of an amorphous structure. In comparison to controls, the application of 1-MCP significantly inhibited increments in L* values as well as grease scores while also reducing accumulation rates for oily waxes throughout most stages over its shelf period, additionally delaying transitions from flaky-wax structures towards their amorphous counterparts. During the initial 7 d of storage, several enzymes involved in the biosynthesis and metabolism of greasy wax components, including lipoxygenase (LOX), phospholipase D (PLD), and β-ketoacyl-CoA synthase (KCS), exhibited an increase followed by a subsequent decline. The activity of LOX during early shelf life (0–7 d) and the KCS activity during middle to late shelf life (14–21 d) were significantly suppressed by 1-MCP. Additionally, 1-MCP effectively maintained firmness, total soluble solid (TSS) and titratable acid (TA) contents, peroxidase (POD), and phenylalanine ammonia-lyase (PAL) activities while inhibiting vitamin C degradation and weight loss. Furthermore, it restrained polyphenol oxidase (PPO) activity, ethylene production, and respiration rate increase. These findings demonstrate that 1-MCP not only delays the onset of peel greasiness but also preserves the overall storage quality of 'Yuluxiang’ pear at a temperature of 20°C. This study presents a novel approach for developing new preservatives to inhibit pear fruit peel greasiness and provides a theoretical foundation for further research on pear fruit preservation.

Effect of perforated low-density polyethylene films on postharvest quality of avocado fruit

Avocado (Persea americana Mill.) being a climacteric fruit, is very prone to quality deterioration and spoilage due to high metabolic activities which leads to postharvest and economic losses. The purpose of this study was to evaluate the impact of perforated low-density polyethylene (LDPE) packaging films on postharvest quality and shelf life of ‘Fuerte’ avocado. Fruit were packaged in LDPE plastics (20 and 40 μm) whereas unpackaged fruit were considered as control. Fruit were kept at ambient environments (21 ± 1 °C and 60.0 ± 5% RH) for 12 days and sampled at 4 days interval. The in-pack avocado created a suitable headspace with low O2 and high CO2 concentrations, which yielded improved preservation of postharvest quality and prolonged shelf life of the avocado. Fruit packed in both 20 and 40 μm LDPE films had lower ethylene production and respiration rates, weight loss, firmness loss, preserved fruit size, high pH, titratable acidity, low soluble solid content, sugar:acid ratio, malondialdehyde content and lipoxygenase activity compared to control. Fruit in LDPE films had no symptoms of decay (20 μm) and slight incidence and decay (40 μm) and were markable during shelf life compared to control fruit had severe decay symptoms and were unmarkable at the end of shelf life. These findings indicated that LDPE films were effective in preserving postharvest quality and extending shelf life of avocado fruit.

Photocatalytic ethylene production by oxidative dehydrogenation of ethane with dioxygen on ZnO-supported PdZn intermetallic nanoparticles

The selective oxidative dehydrogenation of ethane (ODHE) is attracting increasing attention as a method for ethylene production. Typically, thermocatalysts operating at high temperatures are needed for C–H activation in ethane. In this study, we describe a low temperature ( < 140 °C) photocatalytic route for ODHE, using O2 as the oxidant. A photocatalyst containing PdZn intermetallic nanoparticles supported on ZnO is prepared, affording an ethylene production rate of 46.4 mmol g–1 h–1 with 92.6% ethylene selectivity under 365 nm irradiation. When we employ a simulated shale gas feed, the photocatalytic ODHE system achieves nearly 20% ethane conversion while maintaining an ethylene selectivity of about 87%. The robust interface between the PdZn intermetallic nanoparticles and ZnO support plays a crucial role in ethane activation through a photo-assisted Mars-van Krevelen mechanism, followed by a rapid lattice oxygen replenishment to complete the reaction cycle. Our findings demonstrate that photocatalytic ODHE is a promising method for alkane-to-alkene conversions under mild conditions.

Effect of microperforation on quality of modified atmosphere packaged cut rose cv. Corola

ABSTRACT The physiological changes in cut flowers after harvest accelerates their senescence process and greatly affects the quality of cut flowers. Thus the preservation technology is a key factor in limiting the development of the cut-flower industry. The objective of the present study was to explore a new method of preserving cut roses to reduce post-harvest storage and transportation losses. Cut roses were packaged in polyethylene (PE) bags of 40 × 110 cm, with 0, 2, 6, 20, and 30 microperforations of 600 μm at 4°C. The adjustment of the number of microperforations allowed the control of gas concentrations inside the packaging, and those with 20 microperforations permitted the best quality characteristics at 4°C. The findings revealed variations in the gas environment within modified atmosphere packaging (MAP) with different numbers of micropores, which exerted diverse effects on the preservation of cut rose flowers. The MAP with 20 micropores demonstrated the most effective preservation outcome. It not only effectively maintains the antioxidant capacity, the vitality of POD, SOD, and anti-superoxide anion in cut roses but also inhibits the accumulation of H2O2 content. Additionally, it effectively maintained the storage quality by inhibiting the respiration rate, ethylene production rate, and decay rate in cut roses.