Postharvest Decay Research Articles

Chitosan Based Edible Coatings: Enhancing Shelf Life and Quality in Fruits and Vegetables

Chitosan-based edible coatings have gained considerable attention as a sustainable solution for harvested fruits and vegetables which are highly prone to post harvest decay and quality deterioration during storage. Chitosan, derived from chitin exhibits biocompatibility, biodegradability and antimicrobial properties making it an ideal material for edible coatings. Edible coating act as effective barriers to moisture loss, gas exchange and microbial contamination thereby enhancing the quality and extending the shelf life of produce. Research has shown that chitosan coatings can significantly reduce respiration rates, inhibit enzymatic browning and preserve the sensory qualities of fruits and vegetables, contributing to a reduction in food waste and improved food security. The effectiveness of chitosan based coating is influenced by factors such as chitosan concentration, the addition of other natural additives and the methods of application. Studies have demonstrated that chitosan coatings alone or in combination with essential oils or plant extracts effectively reduce weight loss, maintain firmness and prevent spoilage in horticultural perishables. Additionally, nano-encapsulated chitosan formulations have been explored for their enhanced protective effects offering more uniform coatings with superior barrier properties. The application of chitosan coatings is expected to evolve with the integration of nanotechnology, the development of functionalized chitosan molecules and the use of biocompatible additives. Chitosan coatings have been successfully applied commercially, such as in the preservation of perishables illustrating their potential as a sustainable solution with practical benefits for both scientific advancement and industrial application These innovations will further improve the efficacy of coatings by enhancing their moisture and gas barrier properties along with antimicrobial and antioxidant properties. Additionally, sustainability concerns are driving research into eco-friendly sources of edible coating and chitosan is a promising alternative to synthetic or chemical ingredients or fungicides. As the technology advances, chitosan based edible coatings are likely to have increased commercial adoption due to its sustainable and biodegradable nature. However, Chitosan-based coatings face challenges with solubility, application consistency, scalability, cost, allergen concerns, and varying regulatory standards.

Building a protective shield: The role of wound healing in reducing postharvest decay and preserving quality of citrus fruit1

Postharvest citrus fruit is susceptible to pathogenic infestation and quality reduction through wounds, leading to tremendous commercial losses. Herein, wound healing of citrus fruit was obviously at 25°C for five days to form a barrier effective against the development of infectious diseases and water dissipation. Combined with the results of transcriptional and metabolic levels, wound healing activated the expression of CsKCS4, CsKCS11, CsCYP704B1, CsFAH1, CsGPAT3 and CsGPAT9 genes in suberin biosynthesis pathway, and CsPMEI7, CsCesA-D3, CsXTH2, CsXTH6, CsXTH22, CsXTH23, CsXTH24, CsC4H and CsCAD genes in cell wall metabolism pathway, leading to the accumulation of suberin monomers and cell wall components. The results of microscopic observations proved wound healing promoted suberin deposition and cell wall strengthening. Meanwhile, wound healing required the provision of energy and precursor substances by carbohydrate metabolism and amino acid metabolism. We provide new insights into the regulatory mechanism of wound healing on improving disease resistance and maintaining the quality of citrus fruit.

Biocontrol potential of Burkholderia gladioli STPT16 on postharvest decay of litchi fruit caused by Peronophythora litchii and Colletotrichum fructicola

Litchi downy blight (LDB) caused by Peronophythora litchii and anthracnose (AD) caused by Colletotrichum species are major pre- and postharvest disease of litchi fruit. Biocontrol agents such as Burkholderia has been applied for controlling postharvest fruit decay. In this work, an endophytic strain SZPT16 isolated from health litchi branch was identified as Burkholderia gladioli and exhibited strong antagonistic activity against mycelial growth and conidia/sporangia germination of two postharvest pathogens. Dual incubation of pathogen and biocontrol agents caused alterations in hyphal and conidial/sporangial structures and severe cell morphology changes such as mycelia deformation, cell wall collapse and cellular disorganization. Cell-free culture filtrates (CF, diluted at 25-fold) of B. gladioli SZPT16 showed an efficient inhibition on postharvest litchi decay by preharvest application (74.77 % protection) and postharvest application (64.68 % and 71.14 % protection for LDB and AD, respectively). Furthermore, UPLC-MS/MS metabolomic analysis identified 41 up-regulated differential metabolites, which mainly included nucleosides, nucleotides, and analogues, organic acids and derivatives, organic oxygen compounds, and organoheterocyclic compounds. This study firstly reported the efficacy of CF of B. gladioli SZPT16 in protecting postharvest litchi fruit against natural and inoculated pathogen infections. The overall results provide a promising alternative to chemical fungicides to control litchi postharvest decay.

Antifungal films for strawberry packaging using carbon quantum dots derived from lemon and onion juice via green hydrothermal method

Fungi are the prime concern since they cause post-harvest decay in fruits such as strawberries; the fungi motivate the need for new antifungal agents. Among all these nanoparticles, the carbon quantum dots (CQDs) show the most promising results for their use in food packaging applications. Lemon carbon quantum dots (LCQD), which is derived from lemon juice, and onion carbon quantum dots (OCQD), which is derived from onion juice, were synthesized using the one-step hydrothermal method. The synthesized materials were then characterized using a transmission electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy. LCQD and OCQD solutions were applied to fresh strawberries for the purpose of conducting studies on weight loss, decay, and shelf-life extension. The antifungal activity of both CQDs was assessed against Rhizopus sp., Penicillium sp., Candida albicans, Aspergillus sp., and Botrytis cinerea using the agar-well diffusion technique. The obtained average size was 4.33±1.67 nm for LCQDs and 3.34±1.72 nm for OCQDs. Strawberries packaged with OCQDs and LCQDs showed weight loss of 5.21%±1.03% and 8.14%±1.09% on the fourth day of observation, respectively, against 18.71%±2.2% by control. On the same day, the decay rate for OCQDs was 11%, 40% for LCQDs, and 96.65% for control. Both exhibited antifungal activity, with inhibition zones ranging from 12.6-44.5 mm for various fungi. OCQD exhibits higher activity packaging compared to LCQD due to their smaller size and superior antifungal activity against a variety of fungi.

Positive effects of yeast soluble cell wall polysaccharide on fruit postharvest control through resistance response.

Yeast-derived cell wall polysaccharides possess numerous biological activities, but their application in postharvest preservation is rarely reported. The aim of this research was to investigate the effects of Kluyveromyces marxianus soluble cell wall polysaccharide (SCWP) on preventing the infection of Penicillium expansum in pear fruit. The results showed that K. marxianus SCWP treatment could significantly improve the resistance of pear fruit to P. expansum, with respect to Saccharomyces cerevisiae-derived SCWP. Composition of both SCWPs was mannan with the main chains consisting of a→6)-α-D-Manp-(1→unit and the branch structure formed by → 2)-α-D-Manp-(1 except that K. marxianus SCWP took on a shorter side chain and a rougher surface than S. cerevisiae SCWP. In addition, mechanisms of K. marxianus SCWP on stimulating resistance response were associated with the apparent oxidative burst, increased gene expression and enzyme activity of antioxidant and defense systems in pear fruit. Our findings suggest that K. marxianus SCWP can be used as an innovative and promising candidate for preventing postharvest fungal decay and extending fruit shelf life.

Novel Essential Oil-Based Thiosemicarbazone Compounds as Potential Fungicides in Controlling Postharvest Diseases of Citrus Fruit.

To develop novel fungicides for controlling postharvest fungal diseases in citrus fruits, 12 essential oil (EO)-based thiosemicarbazones compounds, termed hydrazine-carbothioamide, were prepared according to the condensation method. In vitro assays showed that compound 13j exhibited the strongest antifungal activity (minimum inhibitory concentration [MIC] = minimum fungicidal concentration [MFC] = 0.0125 mg/mL) against Penicillium digitatum. An in vivo study revealed that 5 × MFC of compound 13j can effectively mitigate the green mold incidence of citrus fruit inoculated with P. digitatum, as well as fruit rot during natural storage, at a level comparable to that of the chemical fungicide prochloraz. Throughout this process, fruit quality was maintained. The hemolysis assay showed that these thiosemicarbazone compounds have good biocompatibility and that their safety is comparable to that of prochloraz. The antifungal activity of compound 13j was attributed to membrane damage, as confirmed using scanning electron microscopy (SEM), Calcofluor white (CFW) staining, propidium iodide (PI) staining, Fourier transform-infrared (FT-IR) spectroscopy, optical density (OD)260, and relative conductivity assays. Collectively, our results indicate that compound 13j can be used as an antifungal agent to control the postharvest decay of citrus fruits.

Zein nanoencapsulation enhances the antifungal activity of thymol for postharvest decay control in bananas

AbstractThe current work describes a nanoparticle system-based approach to enhance the antifungal activity of thymol, a ubiquitous natural antifungal phenolic compound, in postharvest control against banana anthracnose. Thymol was encapsulated within the amphiphilic protein zein by high-shear emulsification, yielding highly dispersible thymol-loaded zein nanoparticles with a high encapsulation efficiency (70%). These particles have an average diameter of 300 nm with spherical morphology, smooth interface, and matrix-type internal structure, as supported by comprehensive structural characterization (dynamic light scattering, transmission electron microscopy and atomic force microscopy). Based on a 40-d storage stability test, thymol was effectively retained within the nanoparticles at 4 °C and ambient room temperature (99% and 97% retention, respectively), despite thymol’s instability and volatility. Antifungal activity assessment against Colletotrichum musae, one of the predominant pathogens that cause banana anthracnose, showed a 200- to 300-fold improvement in the in vitro antifungal activity of thymol. Moreover, the application of thymol-loaded zein nanoparticles as a spray component for banana postharvest treatment demonstrated the efficacy of thymol-loaded zein nanoparticles in preventing and delaying the formation of initial symptoms of banana anthracnose. This appears to arise from the thymol-loaded zein nanoparticles depositing as a film on the banana epidermis, as revealed by atomic force microscopy. Overall, this nanoparticle system offers a new avenue for the design of effective antifungal materials with potential applications in combatting postharvest diseases. Graphical abstract

Combined application of the endophyte Bacillus K1 and sodium dehydroacetate alleviates postharvest gray mold in grapes

Botrytis cinerea, which causes postharvest gray mold, is a primary pathogen that limits grape shelf-life and consumption and causes substantial yield loss worldwide. The combined use of biocontrol agents and food additives has attracted increasing interest. The effects of combined treatment with the endophyte Bacillus subtilis K1 and sodium dehydroacetate (SD) on the occurrence of gray mold and maintenance of grape fruit quality were studied. Treatment with a K1 suspension (1 × 108 CFU/ml) combined with 0.32 g/L SD resulted in markedly improved control of B. cinerea on grapes. The disease incidence and severity in the groups treated with K1 alone or in combination with SD were significantly lower than those in the control groups (P < 0.05) when the mixtures were applied 2 h after pathogen inoculation. Moreover, application of the mixture could maintain the appearance, firmness, total soluble solid (TSS) content and titratable acidity (TA) of grape fruit. Furthermore, the combination triggered increases in the activities of defense-related enzymes such as peroxidase (POD), phenylalanine ammonia lyase (PAL), catalase (CAT), superoxide dismutase (SOD) and polyphenol oxidase (PPO). Additionally, it could increase the vitamin C content. Thus, appropriate combinations of biocontrol agents and chemical reagents can provide effective protection against postharvest decay.

The efficacy of adding some antioxidant compounds in alleviating strawberry fruit rots during storage

BACKGROUND: Postharvest decay caused by Botrytis cinerea (gray mold) and Fusarium solani (fruit decay) negatively affects strawberry fruits during handling and marketing. OBJECTIVE: The effect of cinnamon oil, sodium benzoate, potassium sorbate and/or pomegranate peel powder were estimated on the growth of the two pathogenic fungi and their fruit decay incidence under in vitro and in vivo conditions. METHODS: The isolated fungi from decayed strawberry fruits were identified as Botrytis cinerea and Fusarium sp. The isolated Fusarium sp. was identified molecularly as Fusarium solani and registered in GenBank under accession number ON248575.1 (https://www.ncbi.nlm.nih.gov/nuccore/ON248575.1). RESULTS: Complete fungal growth suppression was observed at a concentration of 3% for all tested materials, Additionally the same (100%) effect was achieved at 2% of a combination of essential oil, salts and pomegranate peel powder. Significant reduction in decay incidence and severity was observed in inoculated strawberry fruits treated with the same concentrations of the tested materials after 10 and 15 days of storage. CONCLUSIONS: The results demonstrate that cinnamon oil, sodium benzoate, potassium sorbate and/or pomegranate peel powder have potency as eco-friendly products, for safe postharvest treatments against strawberry fruit rots during storage. They could be recommended for use in packing-houses due to their wide utilization as safe food preservatives.

Isolation and Identification of Postharvest Rot Pathogens in Citrus × tangelo and Their Potential Inhibition with Acidic Electrolyzed Water.

This study focused on the identification of rot-causing fungi in Citrus × tangelo (tangelo) with a particular emphasis on investigating the inhibitory effects of acidic electrolyzed water on the identified pathogens. The dominant strains responsible for postharvest decay were isolated from infected tangelo fruits and characterized through morphological observation, molecular identification, and pathogenicity detection. Two strains were isolated from postharvest diseased tangelo fruits, cultured and morphologically characterized, and had their gene fragments amplified using primers ITS1 and ITS4. The results revealed the rDNA-ITS sequence of two dominant pathogens were 100% homologous with those of Penicillium citrinum and Aspergillus sydowii. These isolated fungi were confirmed to induce tangelo disease, and subsequent re-isolation validated their consistency with the inoculum. Antifungal tests demonstrated that acidic electrolyzed water (AEW) exhibited a potent inhibitory effect on P. citrinum and A. sydowii, with EC50 values of 85.4μg/mL and 60.12μg/mL, respectively. The inhibition zones of 150μg/mL AEW to 2 kinds of pathogenic fungi were over 75mm in diameter. Furthermore, treatment with AEW resulted in morphological changes such as bending and shrinking of the fungal hyphae surface. In addition, extracellular pH, conductivity, and absorbance at 260nm of the fungi hypha significantly increased post-treatment with AEW. Pathogenic morphology and IST sequencing analysis confirmed P. citrinum and A. sydowii as the primary pathogenic fungi, with their growth effectively inhibited by AEW.

Effects of Meyerozyma guilliermondii PJ15 on the biocontrol of Penicillium crustosum causing postharvest decay in Orah and its influence on the microbial diversity of Orah

Abstract Objectives Isolate biocontrol microorganisms that inhibit Penicillium crutosum, and explore their effects on the microbial control and microbial diversity change of Penicillium crustosum causing postharvest decay in Orah. Materials and Methods The biocontrol effect was verified by confrontation experiment. The microbial diversity was analyzed using high-throughput sequencing technology. Metabolomics analysis was performed using LC-MS/MS. Results a strain of Meyerozyma guilliermondii PJ15 that strongly inhibited Penicillium crustosum was isolated from grape surface, which could effectively inhibit the mycelium growth and green spore production of Penicillium crustosum. PJ15 could reduce the sourness and nutrient loss of Orah caused by Penicillium crutosum. Compared with the control, PJ15 treatment increased pH by 11.32%, soluble protein by 154.51%, ascorbic acid by 160.99%, and soluble total sugar by 203.53%. Microbial diversity analysis showed that PJ15 has a relatively small impact on the bacterial composition and diversity on the surface of Orah, but has a significant impact on the fungal composition and diversity. It can increase the fungal diversity of Orah invaded by Penicillium crustosum, increase the density of fungal interaction networks, and form a stronger coexisting survival interaction network. The vaccination of PJ15 downregulated differential metabolites 5,6-Epoxytetraene, which showed a positive correlation with Penicillium crustosum and a negative correlation with PJ15. Conclusions Meyerozyma guilliermondii PJ15 has a strong inhibitory effect on the growth of Penicillium crustosum, and has a significant impact on the fungal composition and diversity on the surface of Orah. It has the potential for biocontrol of Penicillium crustosum causing postharvest decay in Orah.

Pullulan-based coatings carrying biocontrol yeast mixed with NaCl to control citrus postharvest disease decays

The decline in postharvest citrus quality due to fungal infections necessitates innovative packaging solutions. This study presents a pullulan-based edible film (PBYFs) with biocontrol yeasts, designed to dissolve in both liquid and soil. This film is capable of enveloping entire citrus fruits, effectively managing postharvest diseases, and extending their shelf life. The formulation of PBYFs includes NaCl 0.1 M, Kloeckera apiculata 34–9 at 1.0 × 107 CFU mL−1, pullulan 3 % w/v, SA 0.5 % w/v, and glycerin 1 % w/v. Our experiments, conducted on eight citrus varieties, demonstrated that PBYFs significantly reduced the occurrence of green and blue molds, sour rot, and anthracnose in vivo. Moreover, PBYFs-coated fruits exhibited an extended shelf life without compromising the quality parameters such as weight loss, TSS (total soluble solids), TA (titratable acidity), VC (vitamin C), or the accumulation of off-flavor volatiles. This research presents a promising approach for creating scalable, cost-effective, and environmentally sustainable biodegradable antifungal packaging systems for citrus fruits.

Carbon Dots-Mediated Photodynamic Treatment Reduces Postharvest Senescence and Decay of Grapes by Regulating the Antioxidant System.

Grapes are susceptible to mold and decay during postharvest storage, and developing new technologies to extend their storage period has important application value. Photodynamic technology (PDT) in concurrence with carbon dots (CDs) proposes an innovative and eco-friendly preservation strategy. We examined the effects of carbon dots combined with photodynamic treatment on postharvest senescence and antioxidant system of table grape. The compounding of photodynamic technology with a 0.06 g L-1 CDs solution could possibly extend the postharvest storage period of grape berries. Through this strategy, we achieved a decreased rate of fruit rotting and weight loss alongside the delayed deterioration of fruit firmness, soluble solids, and titratable acid. As paired with photodynamic technology, CDs considerably decreased the postharvest storage loss of phenols, flavonoids, and reducing sugars as compared to the control group. Concurrently, it remarkably postponed the build-up of hydrogen peroxide (H2O2), superoxide anion (O2∙-), and malondialdehyde (MDA); elevated the levels of reduced ascorbic acid (AsA) and reduced glutathione (GSH); lowered the levels of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG); raised the ratios of AsA/DHA and GSSH/GSSG; encouraged the activities of superoxide dismutase (SOD) and phenylalanine ammonia-lyase (PAL); and inhibited the activities of polyphenol oxidase (PPO) and lipoxygenase (LOX). Furthermore, it enhanced the iron reduction antioxidant capacity (FRAP) and DPPH radical scavenging capacity of grape berries. CDs combined with photodynamic treatment could efficiently lessen postharvest senescence and decay of grape berry while extending the storage time.

Modified SiO2@cinnamaldehyde/nanocellulose coating film for loquat preservation

Although cinnamaldehyde (CA) is an excellent antimicrobial agent, its application in the food industry was limited by its volatility and lack of antimicrobial persistence. Herein, aminated hollow mesoporous silica (NH2-HMSN) was prepared by selective etching and amino-modified. Subsequently, long-acting antibacterials with regulated release (NH2-HMSN@CA) were obtained by using NH2-HMSN as cinnamaldehyde carrier. NH2-HMSN@CA can effectively regulate the release of CA, and has 100 % inhibition effect on the growth of E. coli, S. aureus and C. acutatum. In addition, nanocellulose/NH2-HMSN@CA (CHA) coating film was prepared for postharvest preservation of loquat. The coating film effectively improved the storage quality and shelf life of loquat, and delayed the postharvest decay of loquat. The prepared coating film active packaging for long-term preservation is expected to provide a scheme for promoting sustainable preservation of postharvest loquat.

Isolation of Antagonistic Endophytic Fungi from Postharvest Chestnuts and Their Biocontrol on Host Fungal Pathogens.

In this study, antagonistic endophytic fungi were isolated from postharvest chestnut fruits; endophytic antagonistic fungi and their combination of inhibitory effects on the fungal pathogen Neofusicoccum parvum were evaluated. A total of 612 endophytic fungi were isolated from 300 healthy chestnut kernels, and 6 strains out of them including NS-3, NS-11, NS-38, NS-43, NS-56, and NS-58 were confirmed as antagonistic endophytic fungi against Neofusicoccum parvum; these were separately identified as Penicillium chermesinum, Penicillium italicum, Penicillium decaturense, Penicillium oxalicum, Talarmyces siamensis, and Penicillium guanacastense. Some mixed antagonistic endophytic fungi, such as NS-3-38, NS-11-38, NS-43-56, and NS-56-58-38, exhibited a much stronger antifungal activity against N. parvum than that applied individually. Among them, the mixture of NS-3-38 showed the highest antifungal activity, and the inhibition rate was up to 86.67%. The fermentation broth of NS-3, NS-38, and their combinations exhibited an obvious antifungal activity against N. parvum, and the ethyl acetate phase extract of NS-3-38 had the strongest antifungal activity, for which the inhibitory rate was up to 90.19%. The NS-3-38 fermentation broth combined with a chitosan coating significantly reduced N. parvum incidence in chestnuts from 100% to 19%. Furthermore, the fruit decay and weight loss of chestnuts during storage were significantly decreased by the NS-3-38 fermentation broth mixture along with a chitosan coating. Therefore, a mixture of P. chermesinum and P. decaturense could be used as a potential complex biocontrol agent to control postharvest fruit decay in chestnuts.

Antifungal properties and molecular docking of ZnO NPs mediated using medicinal plant extracts

Significant postharvest losses and food safety issues persist in many developing nations, primarily due to fungal activities, including mycotoxin production. In this study, green synthesised zinc oxide nanoparticles (ZnO-NPs) were prepared from leaf extracts of Syzygium cordatum (ZnO 1), Lippia javanica (ZnO 2), Bidens pilosa (ZnO 3), and Ximenia caffra (ZnO 4). Physicochemical characteristics of the ZnO-NPs were determined using X-ray diffraction (XRD), Fourier transmission Infrared spectroscopy and ultraviolet–visible (UV–vis) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD analysis confirmed the presence of a wurtzite crystal structure in the hexagonal shape of the ZnO nanoparticles (NPs), with an average size ranging between 25 and 43 nm. The microscopic examination of the morphology revealed the presence of spherical particles with sizes ranging from 37 to 47 nm in diameter. The antifungal efficacy of the ZnO-NPs was assessed against pathogenic plant fungi, including Botrytis sp. (STEU 7866), Penicillium sp. (STEU 7865), and Pilidiella granati (STEU 7864), using the poisoned food technique. Further antifungal evaluation of the ZnOPs was performed using the broth microdilution assay. A significant interaction between the type of ZnO-NPs and fungal species was observed, with the highest susceptibility in Mucor sp. to ZnO 2, achieving over 50% inhibition. Penicillium sp. also showed high susceptibility to all ZnO-NPs. Molecular docking results confirmed the strong H-bonding interactions of ZnO-NPs with fungal receptors in Mucor sp. and Penicillium sp., Botrytis sp. and P. granati exhibited the least susceptibility. Further tests revealed that ZnO 2 exhibited the highest inhibitory effect on Botrytis sp., with a low minimum inhibitory concentration (MIC) of 25 µg/mL, attributed to its larger positive zeta potential. This study indicates that ZnO NPs, particularly those mediated using Lippia javanica (ZnO 2), have promising potential as effective antifungal agents, which could play a significant role in reducing postharvest decay and losses.

Ozone Treatment as a Sustainable Alternative for Suppressing Blue Mold in Mandarins and Extending Shelf Life

Citrus fruits, particularly mandarins, are highly valued globally for their nutritional benefits and versatile culinary uses. However, the challenge of post-harvest decay, primarily due to blue mold (Penicillium italicum) infections, results in significant food losses and necessitates effective preservation strategies. Traditional methods often rely on fungicides, raising concerns about chemical residues and environmental impact. This study investigates the efficacy of ozone as an alternative approach to controlling blue mold in mandarins. Various gaseous ozone treatments were tested, including single, double, and triple treatments, with durations ranging from 10 to 60 min and concentrations from 3.3 to 20 ppm. Additionally, ozonated water treatments were evaluated with concentrations of 2, 4, and 6 ppm. To simulate a realistic infestation scenario, mandarins were artificially infected with P. italicum spores before undergoing both gaseous ozone and ozonated water treatments. The storage conditions for the mandarins were meticulously controlled, maintaining a humidity level of 50–60% and a temperature range of 10–12 °C. Each fruit was analyzed, and the presence of P. italicum infection was determined two and three weeks after the ozonation. Results indicated that ozone treatments significantly reduced mold growth, with gaseous ozone demonstrating efficacy rates up to 97.5% and ozonated water treatments achieving preservation rates between 95% and 97%. These results underscore ozone’s potential as a safe, efficient, and sustainable alternative to conventional fungicides, offering promising solutions for extending the shelf life of mandarins. Further research is recommended to optimize ozone treatment parameters, assess long-term effects on fruit quality and nutritional content, and refine application techniques to harness ozone’s potential in citrus fruit preservation fully. This approach not only addresses food security challenges but also aligns with global efforts to reduce chemical inputs in agriculture and promote environmentally sustainable practices.

The effect of thymol and carvacrol rich-plant essential oils on controlling postharvest decay molds in orange fruit

The antifungal activity of essential oils of Thymus daenensis, Thymus vulgaris, Satureja hortensis and Satureja khuzistanica as well as their major compounds were studied against mold decays of orange fruit. According to GC-MS analysis, the major compounds of T. danensis essential oil were thymol (65.5%) and alpha-terpinene (11.9%) whereas T. vulgaris was rich in thymol (59%) and p-cymene (15.6%). Carvacrol (88.4%) in S. khuzistanica oil and carvacrol (51%), gamma-terpinene (20.8%) and p-cymene (13.7%) in S. hortensis oil were charecterized as major compounds. The oil of S. khuzistanica and its major compound carvacrol exhibited the strongest fungicide activity against Penicillium digitatum, Rhizopus stolonifer and Colletotrichum gloeosporioides at 300 µL/L. The results on orange fruits exhibited that the use of S. khuzistanica and S. hortensis EOs as spraying and dipping treatments could considerably reduce spoilages decays in the fruit.

Isolation and Phenotypic Identification of Mycotoxigenic Fungi from Stored Maize Kernels within Dutsin–Ma Metropolis, Katsina State

One of the most important effects of post-harvest decay or seed deterioration by fungi is the production of mycotoxins. Mycotoxicosis is a disease of animals and humans following consumption of feeds and foods contaminated by fungi that produce toxic substances called mycotoxins. The study investigated the cultural morphology, microscopic identification, pathogenicity, and mycotoxin production of fungal isolates from 25 stored maize samples collected. Standard microbiological techniques were employed for the analysis of all the samples, Cultural morphology on Potatoes Dextrose Agar revealed diverse colony characteristics, ranging from olive and dark green hues with smooth or spongy surfaces to brownish-pink and dull yellow-green colonies. Microscopic analysis identified six different fungal species, with Aspergillus spp being the most prevalent (72%) and Mucor spp as the least prevalent (6%). Pathogenicity tests on fresh maize demonstrated that all the isolates were pathogenic, causing observable growth on the maize samples. Furthermore, mycotoxin production by the fungal was revealed by evidence of fluorescence under UV radiation, indicating the potential production of aflatoxins. Stored maize kernels from the study area were at risk of fungal attack due to poor storage facilities, poor handling practices and inadequate drying of the grains, which enabled the fungi to grow and produce mycotoxins. Therefore, farmers should be sensitized on the possible risk of fungal attack on grains and be educated on timely harvest, hygienic drying and storage practices of grains.

Chemical induction of DNA demethylation by 5-Azacytidine enhances tomato fruit defense against gray mold through dicer-like protein DCL2c.

Postharvest decay, primarily caused by pathogenic fungi in ripening fruits and fresh vegetables, poses a challenge to agricultural sustainability and results in significant economic losses. The regulation of the fruit ripening by DNA methylation has been well demonstrated, while defense response of fruit underlying epigenetic regulation against postharvest decay remains uncertain. In the present study, treatment of tomato fruits with the DNA methyltransferase inhibitor 5-Azacytidine (5-Aza) notably decreased their susceptibility to gray mold. Following 5-Aza treatment, we observed a substantial increase in activities of chitinase (CHI) and glucanase (GLU) in tomato fruits, as well as an increase in the expression of the dicer-like SlDCL2 gene family. Suppression of SlDCL2c through double-stranded RNA-induced RNA interference (RNAi) resulted in a decrease in the expression of chitinases CHI3, CHI9, Class V chitinase, and endochitinase 4 by 71%, 29%, 55%, 64%, as well as glucanases Cel1, Cel2, and GluB by 19%, 93%, and 87%, respectively. This was accompanied by decreased activities of resistance-related enzymes, including CHI and GLU. The expression levels of genes phenylalanine ammonia-lyase PAL2, peroxidase POD 12, POD P7, CCR1, CYP84A2, and COMT in phenylpropanoid biosynthesis pathway also decreased by 33%, 53%, 18%, 50%, 30%, and 24% in SlDCL2c-RNAi fruit, resulting in decreased activities of PAL and POD. Consequently, the lesion diameter of gray mold in SlDCL2c-RNAi fruit increased by 55% compared to the control group. Overall, the present study indicated that DNA methyltransferase inhibitor 5-Aza reduces susceptibility of tomato fruit to gray mold through regulation of DCL2c-mediated inducible defense response.