Postharvest Quality Research Articles

Beeswax: A review on the recent progress in the development of superhydrophobic films/coatings and their applications in fruits preservation.

Recently, the design and fabrication of bio-inspired superhydrophobic materials using natural lipid additives such as beeswax (BW) have aroused great attention in food packaging as they can minimize the transfer rate of water molecules and have effective moisture barriers. This review discusses the recent progress in the design and fabrication of BW-containing edible films/coatings (e.g., emulsion and blend films, bilayer materials, bionanocomposites, and antimicrobial materials) and their potential applications on the postharvest life and quality attributes of various fruits. Incorporation of BW into polysaccharides- and proteins-based emulsion films effectively improved their hydrophobicity, water vapor, and UV/visible light barrier properties, as well as the film tensile properties. The addition of nanoparticles to BW-based polymeric matrices often results in improved physico-mechanical properties. BW coatings have been also applied to prolong the shelf-life of various climacteric fruits, however, optimization of the wax concentration can be further investigated to develop targeted food storage systems.

Melatonin treatment maintains the quality and delays senescence of postharvest cattails (Typha latifolia L.) during cold storage.

Melatonin treatment was investigated for the sensory quality and senescence in postharvest cattails (Typha latifolia L.) during cold storage. The 0.75mM melatonin treatment reduced surface browning and delaying lignification of Cattails stored at 4°C. The results showed that melatonin treatment slowed weight loss and firmness, maintained sensory quality and reducing sugar content. Melatonin treatment reduced browning by inhibiting the increase of MDA and H2O2 contents and POD activity. Melatonin treatment maintained high non-enzymatic antioxidant components (Vitamin C and total phenolic content) and antioxidant enzyme activities (SOD, CAT, and APX), thereby alleviating the browning and senescence of postharvest cattails. These findings indicate that melatonin treatment can maintain postharvest cattails quality.

Foliar application of chitosan and plant probiotic bacteria influencing the growth, productivity and bulb storage life of onion

Onion having several health promoting phytochemical contents is an important spices in most of the countries of the world as well as vegetables in particular and chitosan and plant probiotic bacteria are few proven natural growth enhancing agents. Here, three bio-stimulants namely Chitosan (100 and 200 ppm), Paraburkholderia BRRh-4 bacteria (1.5 × 109 CFU mL-1) and Clybio (0. 1%) in singly as well as combining one another were applied at twelve different treatment combinations including control with the aim of investigating the below and above ground vegetative growth, bulb productivity and post-harvest storage performance of onion cv. “Taherpuri”. The experiment was set up in Randomized Complete Block Design (RCBD) maintaining three replicates and conducted during November 2019 to June 2020 where the bio-stimulant formulations were sprayed in the foliage at 20, 40 and 60 days after transplanting (DAT). Reproductive behaviors of the onion cultivar differed significantly among the treatments and those were the resultants of statistically varied vegetative performances recorded at 30, 60 and 90 DAT. Chitosan @ 100 ppm + Clybio (0.1%) + Paraburkholderia BRRh-4 (1.5 × 109 CFU mL-1) combination exhibited statistical superiority over the other treatments in terms of plant height (53.230 cm), number of leaves (10.13/plant), leaf length (41.20 cm) and diameter (10.33 mm), number of roots (32.53/plant), root length (12.23 cm), neck and bulb diameter (11.20 mm and 4.83 cm, respectively) and bulbing ratio (0.23) at 90 DAT. While, shoot and root growth didn’t vary significantly at earlier stages (at 30 DAT). Again, the highest yield (3.36 kg/plot and 10.45 t/ha) was also obtained from Chitosan @ 100 ppm + Clybio (0.1%) + Paraburkholderia BRRh-4 (1.5 × 109 CFU ml-1) treatment. The combination of chitosan and probiotic bacteria had significant influence on post-harvest storage qualities of onion where the longest shelf life/marketable life (8.17 months) with the lowest physiological weight loss and bulb rotting at 90 days after harvest was administered in Chitosan @ 100 ppm + Clybio (0.1%) + Paraburkholderia BRRh-4 (1.5 × 109 CFU mL-1) treatment. Besides the best treatment, Chitosan @ 100 ppm + Clybio (0.1%) and Chitosan @ 100 ppm + Paraburkholderia BRRh-4 (1.5 × 109 CFU mL-1) produced statistically superior results over control for onion growth and development. Therefore, chitosan and plant probiotic bacteria can be judiciously used for quality onion production in the warm and humid areas of the world

Effect of gamma irradiation on post-harvest quality of king oyster mushrooms (Pleurotus eryngii)

The consumption of king oyster mushrooms has steadily increased owing to their unique flavor and delicate texture. This study extended the storage period of king oyster mushrooms (Pleurotus eryngii) via gamma irradiation. Irradiated samples (0, 0.5, 1, 2, and 3 kGy) were stored at 4°C with 80% relative humidity for up to 28 days, and the experiments were conducted every 7 day. Microbiological analysis revealed a dose-dependent reduction in total aerobic bacteria, Pseudomonas spp., and yeasts and molds, and gamma irradiation above 2 kGy effectively controlled microbial contamination for up to 28 days. At the 28th day of storage, the irradiated king oyster mushrooms exhibited delayed browning through the reduction of tyrosinase activity. Moreover, firmness reduction (%) was 80.59±1.89% for the non-irradiated group and 42.80±1.28, 34.57±1.13, 31.05±3.24, and 39.73±0.94% for the irradiated group (0.5, 1, 2, and 3 kGy), respectively. These results were supported by the scanning electron microscopy photos, which showed smaller pores in the irradiated group than in the non-irradiated group. This study demonstrated that 2 kGy of gamma irradiation effectively reduces microbial contamination and delays the browning and softening of king oyster mushrooms for up to 28 days.

Ecofriendly System Based on Mesoporous Silica Nanoparticles Delivery of Chitosan to Control Soft Rot Disease and Maintain Postharvest Quality of Tuber Potato

Ecofriendly System Based on Mesoporous Silica Nanoparticles Delivery of Chitosan to Control Soft Rot Disease and Maintain Postharvest Quality of Tuber Potato

Improving the post-harvest quality of fruits during storage through edible packaging based on guar gum and hydroxypropyl methylcellulose

Fruits are particularly susceptible to post-harvest decay. In this context, bio-based coatings could be a useful and sustainable approach to overcome this problem. The EU Commission is very restrictive about food additives and materials in contact with food, regulated respectively by Reg. UE (CE) 1333/2008 and Reg. UE (CE) 10/2011. In this research, different percentages of hydroxypropyl methylcellulose (H)-guar gum (G) (1–2% w/v) and potassium sorbate (PS) (0–2% w/v) were used to produce coatings to be applied on tomatoes (Solanum lycopersicum) and oranges (Citrus sinensis). The efficacy of the coatings was firstly evaluated through an accelerated test (28 °C 90% RH, 20 days) on artificially wounded fruits, and then under storage conditions (8 °C 95% RH, 6 weeks). The physical and chemical parameters of the fruits were periodically analyzed and used to evaluate the effect of the coatings on the fruit quality through a multivariate approach (PCA). All coatings were effective in preserving fruits under refrigeration against Penicillium spp. and Alternaria spp., but PS led to significant fruit weight loss despite its strong fungistatic activity. Biopolymers showed potential for preserving fruit freshness, but alternative antifungal agents without adverse weight effects should be explored using a similar statistical approach.

Biomarkers of postharvest resilience: unveiling the role of abscisic acid in table grapes during cold storage.

Table grapes are considered non-climacteric fruit, not showing a rapid increase in respiration rate and ethylene production during ripening. Previous research has suggested that abscisic acid (ABA) may have a more crucial role in grape postharvest behaviour. This study aimed to identify biomarkers of postharvest resilience and flavour life of imported table grapes. An experiment was designed to determine i) the role of ABA and catabolites on grape berry senescence; ii) the spatial distribution of these hormones within the grape berry, and iii) the effect of 1-MCP and storage temperature on its postharvest quality. Hence, the use of an ethylene inhibitor, 1-methylcyclopropane (1-MCP), during table grape storage was investigated. Table grapes (Vitis vinifera L.) cv. 'Krissy' were subjected to i) control (untreated); and ii) 1-MCP (1 µL L-1; 12 hours; 15°C) and stored under two scenarios: i) 15 days at 0.5°C, followed by five days at 5.5°C to simulate shelf-life; and ii) 20 days at 5.5°C to simulate a higher storage temperature followed by shelf-life. Physiological (i.e. mould incidence, skin colour, firmness, respiration rate) and biochemical analysis (i.e. individual sugars, organic acids, abscisic acid and catabolites) were performed. Grapes subjected to 5.5°C showed significantly higher mould incidence at the end of the shelf-life compared to 0.5°C storage temperature (12.6% vs. 3.1%). Also, and for the first time, the spatial distribution of ABA during the senescence of table grapes was profiled; the distal section had three times more ABA and metabolites than the proximal. We demonstrated that senescence processes were initiated after a significant increase in respiration rate (from 1 to 2.8 mL CO2 kg-1 h-1), and that ABA could be considered a biomarker for table grapes senescence, since an ABA peak preceded the increase in respiration rate, mould incidence, organic acids, and sucrose hydrolysis during postharvest storage; and coincided with a decrease in berry firmness. These findings are of significant importance for the industry as understanding how ABA regulates both senescence processes and quality changes during postharvest cold storage of tables grapes can improve the consistency and reduce waste and consumer complaints.

Potassium-phosphorus fertilization to reduce salt stress in West Indian cherry

West Indian cherry stands out in the Brazilian fruit scenario due to the nutritional quality of its fruits, making it a promising crop in the generation of employment and income. However, the occurrence of water sources with high concentrations of salts is a limiting factor for the expansion of crop area. In this context, the objective was to evaluate the production and post-harvest quality of West Indian cherry cv. BRS 366 Jaburu under prolonged saline stress and potassium-phosphorus fertilization combinations in the second year of cultivation. The experiment was carried out in 250 L lysimeters in a greenhouse in the municipality of Campina Grande-PB, Brazil. Treatments were distributed in randomized blocks in a 5 × 4 factorial scheme, with five levels of electrical conductivity of irrigation water - ECw (0.6, 1.4, 2.2, 3.0, and 3.8 dS m−1) and four combinations of potassium-phosphorus fertilization (100/100, 85/85, 60/60, and 45/45% of K2O/P2O5 recommendation for the second year of cultivation) with three replicates. Irrigation water salinity of up to 3.8 dS m−1 does not compromise the post-harvest quality of West Indian cherry. The increase in water salinity reduces mean fruit weight and water consumption of plants, while waters with electrical conductivities of 3.0 and 2.0 dS m−1 promote the maximum values of total soluble solids and ascorbic acid in the fruits, respectively. The supply of 45/45% K2O/P2O5 of the fertilization recommendation provides the higher content of ascorbic acid in West Indian cherry fruits and, when associated with ECw of 1.4 dS m−1, promotes the higher production of the crop.

The combined application of Debaryomyces hansenii and Bacillus atrophaeus inhibits disease development and enhances postharvest quality in litchi fruit by activating flavonoid metabolism

Our previous study demonstrated that the postharvest application of Debaryomyces hansenii (Y-1) and Bacillus atrophaeus (TE-7) significantly reduced decay in litchi fruit, however, the molecular mechanism was not elucidated. Results of the present study indicated that a combined treatment (Y-TE) using both antagonistic strains significantly suppresses an increase in the disease index and inhibits a reduction in the antioxidant properties of litchi fruit during storage at 25 °C. Transcriptomic analysis revealed that genes enriched in phenylpropanoid biosynthesis, flavonoid biosynthesis and plant-pathogen interaction pathways were involved in the response to theY-TE treatment. RT-qPCR analysis indicated that LcMYB102, LcMYB73, and LcMYB33 transcription factors (TFs), and flavonoid synthesis genes, including LcANS and LcF3H, were significantly up-regulated in litchi fruit by the Y-TE treatment after two days of storage. Moreover, an analysis of the metabolome identified eight differentially expressed metabolites associated with flavonoid synthesis, especially formononetin. Furthermore, the regulation of the major pathway and network for flavonoid biosynthesis in litchi fruit by Y-TE was also observed. In summary, our results indicate that the combined application of Y-1 and TE-7 promotes the accumulation of flavonoids in litchi fruit that enhance disease resistance and contributes to the maintenance of quality during storage. The use of these microbial antagonists represents a potential biological approach for the preservation of litchi fruit.

Nitric oxide regulates the lignification and carotenoid biosynthesis of postharvest carrot (Daucus carota L.)

The carrot is an important horticultural crop of the Apiaceae family, possessing considerable nutritional and economic value. Unfortunately, the decline in the postharvest quality has resulted in a decrease in the desirability of carrots and further food wastage. Nitric oxide (NO) plays a crucial role in alleviating the senescence and reducing losses of postharvest horticultural products, but its impact on the postharvest quality of carrots has not been reported. In this study, the effects of treatment with ddH2O, varying concentrations of sodium nitroprusside (SNP), and carboxy-PTIO (cPTIO) on the whiteness index, weight loss, and sensory scoring were evaluated, and a concentration of 1.5 mM SNP treatment preserved the appearance quality of postharvest carrots. Further analysis revealed that SNP treatment led to an increase in endogenous NO content by promoting nitrate reductase activity, which subsequently enhanced the expression of DcPSY1, DcPDS1, DcZDS1, DcCRTISO1, and DcLCYB1 and increased the levels of total carotenoid, α-carotenoid, and β-carotenoid. The alternation of carotenoids both increased abscisic acid (ABA) level by promoting the expression of ABA biosynthesis genes, but also hindered the generation of hydrogen peroxide and superoxide anion. Meanwhile, the expression of lignin biosynthesis genes was downregulated in SNP treatment group, resulting in postharvest carrots with lower lignin content and a lower degree of cell lignification. Overall, our findings provide a theoretical basis for the application of NO in the postharvest preservation of carrots and shed light on the role of NO in regulating the synthesis mechanisms of carotenoids and lignin in postharvest carrots.

A regression model of electron-beam generated X-ray irradiation on postharvest quality of kiwifruit based on electrical properties

This study aimed to investigate the effect of the X-ray on the postharvest quality of kiwifruit and to develop a mathematical model based on electrical properties. Xuxiang kiwifruit was irradiated at different doses (0, 0.2 and 0.4 kGy) by electron-beam generated X-ray to determine physiological and biochemical indexes, relative gene expression of enzymes, and 12 electrical parameters of kiwifruit at frequencies from 100 to 3,980,000 Hz. Results revealed that both irradiation groups significantly inhibited the decline in hardness, vitamin C (VC), and titratable acidity (TA) while reducing weight loss and malondialdehyde (MDA) accumulation. The 0.4 kGy irradiation group also maintained higher antioxidant enzyme gene expression and activity, and lower cell wall degrading enzyme gene expression and activity. Correlation and principal component analyses were used to identify eigenfrequencies of 3,980,000 Hz for the control and 0.2 kGy irradiation groups and 2,510,000 Hz for the 0.4 kGy irradiation group. A linear regression mathematical model was established using these eigenfrequencies and the common sensitive electrical parameter, yielding a 72.33 % accuracy rate for determining soft rot in kiwifruit. Overall, this study provides theoretical and technical support for the use of X-ray irradiation in kiwifruit preservation, storage, and future quality testing of fruits.

Physiological response, phytochemicals, antioxidant, and enzymatic activity of date palm (Phoenix dactylifera L.) cultivated under different storage time, harvesting Stages, and temperatures

The quality of date palm is highly influenced by postharvest techniques, storage, and processing effects. Fruits stored at room temperature result in dehydration, whereas higher temperatures accelerate the enzymatic browning of fruit. This study aimed to enhance postharvest quality of date palms through improved harvesting and storage techniques. The fruits of date palm (Phoenix dactylifera L. cv. Dhakki) were harvested at khalal (mature, firm), rutab (fully ripe), or tamar (dry) stages and stored at different temperatures (12, 18, or 24 °C) for 0, 15, 30, or 45 days. The analysis of the data showed that the studied attributes significantly different at various ripening stages and storage temperatures. The fruits harvested at Khalal stage proved to be the best in retaining moisture content (23.16%), total soluble solids (20.36 oBrix), fruit juice pH (4.97), ascorbic acid (24.65 mg 100 g−1), non-reducing sugars (26.84%), percent acidity (0.39%), antioxidant activity (211.0 mg 100 g−1), total phenolic (40.07 mg100g−1), flavonoids (45.8 mg 100 g−1), tannin (70.7 mg100g−1), catalase (1.82 U g−1), peroxidase (1.4 U g−1), soluble protein (38.2 mg kg−1), brightness (29.9), chroma (16.4), hue angle (34.9), color (16.8), and with minimum weight loss (8.48%) as compared to fruit harvested at Rutab and Tamar stage. Regarding the means for storage temperature, the fruits stored at 12 ± 3 °C retained the highest moisture content (23.2%), total soluble solids (13.5 oBrix), fruit juice pH (5.42), percent acidity (0.29%), ascorbic acid (24.4 mg100g−1), reducing sugars (31.1%), non-reducing sugars (26.5%), antioxidant activity (214.6 mg100g−1), total phenolic (41.6 mg100 g−1), flavonoids (44.7 mg100 g−1), tannin (71.7 mg 100 g−1), catalase (1.56 U g−1), peroxidase (1.21 U g−1), soluble protein (31.8 mg kg−1), brightness (28.8), chroma (15.3), hue angle (29.6), color (16.2),with minimum weight loss (9.91%). It was concluded that for quality fruit production of date palm cv. Dhakki could be harvested at Khalal stage and stored at a temperature of 12 ± 3 °C.

Effect of Different Doses of Calcium and Boron Pre-harvest Spray on Post-harvest Quality of Acid Lime (Citrus aurantifolia var. SunKagati-1)

Acid Lime (Citrus aurantifolia var. SunKagati-1) has been cultivated in 67 districts of Nepal. Its cultivation is becoming increasingly popular among farmers in Nepal. However, adequate post-harvest loss reduction measures are lacking. A field experiment was conducted in lime orchards in Chitwan during August-September 2019 and 2020. Pre-harvest spraying of different concentrations of calcium (0.1, 0.2, and 0.3%) and boron (0.2, 0.4, and 0.6%) in lime fruit trees was done before 45 and 30 days of fruit harvest. Fruits with the same maturity indices were harvested separately from the treated plants. The post-harvest study was conducted for 1 month under laboratory conditions. Different parameters like physiological loss of weight (PLW), decay loss, total soluble solids (TSS), titrable acidity (TA), ascorbic acid content (vitamin C), and freshness were recorded. Minimum PLW (18.2%) and decay loss (14.3%) were observed in boron (@0.6%) treated fruits. At the end of the experiment, minimum TA (1.79 and 2.12%) was recorded from boron (@0.6%) treated fruits in both years. Calcium (@0.3 %) and boron (@0.4 %) treated fruits expressed the maximum values for TSS in 2019 (9.67ºbrix) and 2020 (7.73 ºbrix), respectively. Fruit harvested from fruit trees sprayed with boron (@0.6%) showed the highest ascorbic acid content (55.47 and 49.61 mg/100g) and better lime freshness (2.67 and 3.0) in 2019 and 2020, respectively. This study concluded that the use of boron @0.6% as a pre-harvest spray can prolong the storage life of sour lime and maintain the fruit quality under environmental conditions of a mid-hill situation.

Usage of chitosan from Hermetia illucens as a preservative for fresh Prunus species fruits: a preliminary analysis

BackgroundFruit and vegetables are highly perishable. In an era where reducing food waste is absolutely essential, packaging is important for maintaining the postharvest quality of these fresh products. Research is working to reduce the use of synthetic materials, not safe for the environment and human health. In this perspective, chitosan emerges as a viable solution for this purpose, as it is biodegradable, biocompatible and also safe for food application. The growing interest in using insects as a source of chitin has allowed for increased exploitation of insect-based waste products to recover valuable materials, such as biopolymers. The black soldier fly (Hermetia illucens L.) is the most widely reared species in Europe for feed production and waste management.ResultsIn this work, fresh mature apricots (Prunus armeniaca L.), nectarines (Prunus persica vulgaris Mill.) and yellow peaches (Prunus persica var. laevis Gray) were coated with 0.5% and 1% chitosan from the pupal exuviae of Hermetia illucens, applied by spraying and stored at room temperature or 4 °C until they decay. Then, to validate the effectiveness of chitosan as a polymer for fruit preservation, several parameters including pH, TSS and weight loss were evaluated.ConclusionsThe results showed that chitosan derived from the black soldier fly is as effective as or better than the commercially available crustacean chitosan in maintaining more stable some storage parameters in fresh apricots, nectarines and peaches. Thus, insects, especially Hermetia illucens, are confirmed as a viable alternative source of the polymer.Graphical

Natural antioxidants and postharvest quality of grape tomatoes at different ripening stages

The objective of this work was to characterize the 5 classes of grape-type cherry tomatoes of sweet heaven variety based on the instrumental color. The experiment was carried out in a completely randomized design (CRD), with five stages of maturation (treatments) and five replications. The contents of the bioactive compounds (total phenolic compounds, total carotenoids, lycopene and flavonoids) and the physicochemical characteristics (pH, total soluble solids, total titratable acidity and SST/ATT ratio) were evaluated. Data were submitted to the Shapiro-Wilk normality test and the Bartlett homogeneity test, and for those that did not meet, the Kruskall Wallis nonparametric equivalent ANOVA test was used, followed by Dunn's test. The results showed a reduction in the total titratable acidity content; an increase in pH, total soluble solids and SST/ATT ratio. The samples collected in the mature stage showed the highest concentrations of bioactive compounds and antioxidant capacity. Despite presenting superior characteristics in relation to the other stages, the harvest of tomatoes at this stage becomes compromised due to their perishability to handling. Yet, the joint assessment of quality attributes can improve the identification of maturation stages, in order to ensure the delivery of a product that satisfies consumer requirements.

Postharvest Quality Exploration of “Crystal” Grapes in Karst Mountainous Area: Regulatory Effect of High Concentration 1-MCP Fumigation

The comprehensive exploration and thorough understanding of the physicochemical characteristics of “Crystal” grapes in the Karst area of Southwest China can not only produce edible table grapes, but also offer significant theoretical backing for the management of rocky desertification in the Karst area and consequently generate enhanced social and ecological benefits. This study explored the regulatory effect of 1-MCP fumigation on the postharvest storage quality of "Crystal” grapes, aiming to provide some technical support for the development of the grape industry in the Karst mountainous areas. The results indicate that compared with the control group, both the 10.0 and 50.0 μL/L 1-MCP treatment groups effectively inhibited the increase in decay rate, browning rate, shedding rate, and color change of the grapes, significantly inhibited the enhancement of polyphenol oxidase (PPO), peroxidase (POD), and lipoxygenases (LOX) browning-related enzyme activities, improved the superoxide dismutase (SOD) activity of the fruits, hindered the decrease of ascorbic acid (AsA) and polyphenols, delayed the accumulation of malondialdehyde (MDA) content, and significantly postponed the peak period of polygalacturonase (PG) activity in the fruits and the degradation of protopectin to soluble pectin, thereby maintaining desirable texture characteristics. The utilization of 1-MCP for fruit fumigation yielded a heightened overall fragrance, thereby facilitating the emission of terpenes, alcohols, aldehydes, ketone aromatic compounds, and methyl aromatic substances within the fruit. Overall, both the M10 and M50 treatments are equally effective in preserving the storage quality of “Crystal” grapes. Under the condition of ensuring the excellent edible quality of crystal grapes, M2 can extend the shelf life of crystal grapes by about 5 days, and M10 and M50 can extend the storage period of crystal grapes by 10~15 days. Considering the cost, it is recommended that the industry employs a concentration of 10.0 μL/L of 1-MCP for “Crystal” grapes. Simultaneously, this study also provides theoretical support for the ecologically high-quality development of cultivated land in the Karst mountainous area of Guizhou and tree selection.

Effect of Humidity-Triggered Controlled-Release 1-Methylcyclopropene (1-MCP) on Postharvest Quality of Papaya Fruit

Papaya (Carica papaya L.) is a valuable economic crop that is widely cultivated in tropical and subtropical regions but has a short storage and shelf life. Exploring effective strategies to improve the postharvest quality of papaya is important. This study explored the effect of humidity-triggered controlled-release 1-methylcyclopropene (1-MCP) sheets on the postharvest quality of papaya fruit. ‘Rainbow’ papayas underwent cold storage at 10 ± 0.5 °C, RH 85% ± 2% for 14 days, and then were transferred to 20 ± 0.5 °C, RH 85% ± 2% for 10 days to simulate shelf life. The 1-MCP sheets were cut into different sizes and placed in storage containers in advance to create corresponding concentrations at 0.5, 1.0, 2.0, and 4.0 ppm. Results showed that 1-MCP treatment inhibited fruit softening, and reduced weight loss and peel color deterioration without causing any physiological disorders. The 1.0–2.0 ppm 1-MCP-treated fruit received the highest score for papaya flavor and sweetness respectively and the lowest score for off-flavor. The humidity-triggered controlled-release 1-MCP sheets are effective and convenient, and they can serve as an important tool for regulating postharvest papaya ripening with economic benefits.

Improved sustained-release properties of ginger essential oil in a Pickering emulsion system incorporated in sodium alginate film and delayed postharvest senescence of mango fruits

The insufficient water vapor barrier and mechanical capacity of sodium alginate (SA) film limited its application in fruit preservation. Herein, cellulose nanocrystals (CNCs) were used to stabilize Pickering emulsion. Then, we prepared SA composite films. Ginger essential oil (GEO) was loaded as antimicrobials and antioxidants. Finally, the application on mangos were investigated. Compared to coarse emulsion, Pickering emulsion and its film-formation-solution showed more stable system and larger droplet size. The emulsion significantly changed the properties of SA film. Specifically, CNCs improved the thermal, tensile, and barrier properties of the film and GEO enhanced the ultraviolet-visible light barrier capacity. Additionally, the SA/CNC film possessed a homogeneous micromorphology which had a sustained-release effect on GEO, thus maintaining high postharvest quality and long-term bioavailability for mangos. In conclusion, the film prepared via Pickering emulsion showed satisfactory properties which had great potential in fruit preservation.

Starch/carboxymethyl cellulose-based photodynamic packaging material delays the quality deterioration of snap beans via ROS metabolism regulation

Snap beans (Phaseolus vulgaris L.) are prone to rapid senescence and quality deterioration during postharvest storage. In this study, the effect of a novel carbon dot/g-C3N4-mediated starch/carboxymethyl cellulose-based photodynamic film (CCPF) on the postharvest quality deterioration and reactive oxygen species (ROS) metabolism of snap bean pods was investigated. CCPF packaging influenced gas composition regulation, ethylene degradation and microbial infection, which resulted in snap bean pods with lower respiratory metabolism and less quality loss. In addition, the snap bean pods in the CCPF group maintained the content of nonenzymatic antioxidants, low activities of pro-oxidative enzymes and high activities of antioxidant enzymes compared to other groups, thus decreasing electrolyte leakage, malondialdehyde accumulation, H2O2 accumulation and the O2·- generation rate. Overall, CCPF packaging effectively delayed postharvest senescence and extended the shelf life of snap beans by reducing respiration and regulating ROS metabolism. Pearson’s correlation analysis confirmed that postharvest senescence correlated with ROS metabolism in snap bean pods. This study offers theoretical evidence for a method to preserve snap bean pods and can be used as a valuable reference for the practical application of novel CCPF packaging.

Bacillus subtilis and Trichoderma harzianum on the quality and occurrence of anthracnose in bananas

The objective of this study was to assess the efficiency of Trichoderma harzianum and Bacillus subtilis on postharvest control of anthracnose, the effects on postharvest quality in ‘Nanicão’ bananas, and the sensory acceptance of fruits. In vitro and in vivo tests were performed. The in vitro tests included the following treatments: control (distilled water), T. harzianum, B. subtilis, and thiabendazole. In vitro tests consisted of pairing Colletotrichum musae with T. harzianum and B. subtilis by daily measuring the mycelial growth of C. musae and by counting the spore germination of C. musae. For in vivo tests, the treatments were control (distilled water), T. harzianum, B. subtilis, T. harzianum + B. subtilis, and thiabendazole. In vivo tests consisted of a daily evaluation of the incidence and severity of anthracnose in ‘Nanicão’ bananas. Some physicochemical characteristics of fruits were evaluated (weight loss, color, pulp firmness, soluble solids (SS), titratable acidity (TA), pH, and SS/TA ratio), as well as the sensory acceptance of bananas. Based on the results, the application of T. harzianum in ‘Nanicão’ bananas was efficient in decreasing the severity of anthracnose caused by C. musae, but treatments with biological control agents were inefficient in this process. On postharvest quality, treatments with biological control agents seem to have accelerated the maturation process. However, results from the sensory analysis showed that fruit acceptance was not affected.