Potential of UVC germicidal irradiation in suppressing crown rot disease, retaining postharvest quality and antioxidant capacity of Musa AAA "Berangan" during fruit ripening

Recent advances on postharvest technologies of bell pepper: A review

The bell pepper (Capsicum annuum L.) is a commercially important horticultural crop grown in tropical and sub-tropical areas across the world. Despite this importance, it is a perishable vegetable with a limited shelf life and high disease susceptibility. Bell pepper output has expanded significantly in recent years. However, this crop is still experiencing close to 40% postharvest losses annually. Chemical fumigation for postharvest disease control of bell pepper has been shown to be efficient against fungal infections, but environmental impact and consumption hazards limit its full use. Recently, non-chemical techniques including biological and botanical methods, non-destructive technologies and Artificial intelligence have been demonstrated to be effective as postharvest management of bell pepper. The paper provides exciting information on recent and emerging techniques for curtailing these losses in bell pepper, alongside their mechanism and existing benefits. The current limitations of these techniques as well as recommendations for potential applications are also addressed.

Study of banana preservation extension by UVC radiation in precise monitoring LED irradiation cavity

Ultraviolet C (UVC) radiation has been considered a possible option to alleviate the seriousness of black spots on bananas during preservation which help increase economic efficiency. In this study, using 275 nm UVC light-emitting diodes (LEDs), a preliminary cavity with dimensions of 30 × 30 × 30 cm was designed and fabricated to aid in reducing black spots on bananas with the aim of application in the factory conveyor belts. The UVC irradiance distribution was thoroughly monitored for many sections at different box heights in both simulation and measurement, with a dominant range of 6-9 W/m2 in the middle. Afterward, trials were conducted in vitro and in vivo at different selected UVC doses. The results in vitro revealed that a dose of over 0.36 kJ/m2 has an excellent effect on inhibiting the colonial germination of fungal Colletotrichum musae, a common species of fungi causing black spot disease on bananas. In vivo conditions, with a short exposure time of around 5 s, the black spots on UVC-irradiated banana peel significantly reduced with minimal sensory damage compared to a control banana via observation after seven days from treatment. Finally, the optimal UVC dose is proposed from 0.030 to 0.045 kJ/m2 for the one-time treatment when considering the upper surface of the banana. With flexibility advantage and short exposure time, the fabricated cavity (box) promises to bring a lot of application potential to aid banana preservation in factories and households.

Combined Transcriptome and Metabolome Analysis of Musa nana Laur. Peel Treated With UV-C Reveals the Involvement of Key Metabolic Pathways

An increasing attention is being given to treat fruits with ultraviolet C (UV-C) irradiation to extend shelf-life, senescence, and protection from different diseases during storage. However, the detailed understanding of the pathways and key changes in gene expression and metabolite accumulation related to UV-C treatments are yet to be explored. This study is a first attempt to understand such changes in banana peel irradiated with UV-C. We treated Musa nana Laur. with 0.02 KJ/m2 UV-C irradiation for 0, 4, 8, 12, 15, and 18 days and studied the physiological and quality indicators. We found that UV-C treatment reduces weight loss and decay rate, while increased the accumulation of total phenols and flavonoids. Similarly, our results demonstrated that UV-C treatment increases the activity of defense and antioxidant system related enzymes. We observed that UV-C treatment for 8 days is beneficial for M. nana peels. The peels of M. nana treated with UV-C for 8 days were then subjected to combined transcriptome and metabolome analysis. In total, there were 425 and 38 differentially expressed genes and accumulated metabolites, respectively. We found that UV-C treatment increased the expression of genes in secondary metabolite biosynthesis related pathways. Concomitant changes in the metabolite accumulation were observed. Key pathways that were responsive to UV-C irradiation include flavonoid biosynthesis, phenylpropanoid bios6ynthesis, plant-pathogen interaction, MAPK signaling (plant), and plant hormone signal transduction pathway. We concluded that UV-C treatment imparts beneficial effects on banana peels by triggering defense responses against disease, inducing expression of flavonoid and alkaloid biosynthesis genes, and activating phytohormone and MAPK signaling pathways.

Postharvest UV-C Irradiation Influenced Cellular Structure, Jasmonic Acid Accumulation, and Resistance Against Green Mold Decay in Satsuma Mandarin Fruit (Citrus unshiu)

Green mold caused by Penicillium digitatum is an important factor limiting the shelf life of mandarin fruit. In this study, the effect of ultraviolet-C (UV-C) irradiation on cellular structure, endogenous jasmonic acid (JA), and development of P. digitatum in satsuma mandarin fruit was investigated. UV-C treatments included 0 (untreated control), 3, and 10 kJ m−2 or the exposure time of 0, 1.18, and 4.52 min, respectively. The UV-C dose of 10 kJ m−2 significantly reduced the development of P. digitatum both in vitro and in vivo, resulting in the maintenance of the cellular structure of the albedo tissue. The production of malondialdehyde (MDA) was decreased upon UV-C treatment of 10 kJ m−2. The concentration of JA increased in the treatment of 10 kJ m−2 compared to the treatment of 3 kJ m−2 and the control. UV-C irradiation increased total phenolic and total flavonoid concentrations and DPPH radical scavenging capacity. These results suggest that UV-C at 10 kJ m−2 has a potential to control green mold caused by P. digitatum, maintain cellular structure, stimulate the accumulation of JA, and induce biochemical compounds in satsuma mandarin.

Combining Chitosan and Vanillin to Retain Postharvest Quality of Tomato Fruit during Ambient Temperature Storage

Tomato, being a climacteric crop, has a relatively short postharvest life due to several factors such as postharvest diseases, accelerated ripening, and senescence that trigger losses in quantity and quality. Chemicals are widely used to control postharvest disease. Inaptly, it leads to detrimental effects on human health, environment and it is leads to increased disease resistance. Chitosan and vanillin could be an alternative to disease control, maintain fruit quality, and prolong shelf life. The aim of this research was to evaluate the potential of chitosan and vanillin coating on the tomato fruit’s physicochemical quality during storage at 26 ± 2 °C/60 ± 5% relative humidity. Chitosan and vanillin in aqueous solutions i.e., 0.5% chitosan + 10 mM vanillin, 1% chitosan + 10 mM vanillin, 1.5% chitosan + 10 mM vanillin, 0.5% chitosan + 15 mM vanillin, 1% chitosan + 15 mM vanillin, and 1.5% chitosan + 15 mM vanillin, respectively, were used as edible coating. The analysis was evaluated at 5-day intervals. The results revealed that 1.5% chitosan + 15 mM vanillin significantly reduced disease incidence and disease severity by 74.16% and 79%, respectively, as well delaying weight loss up to 90% and reducing changes in firmness, soluble solids concentration, and color score. These coatings also reduced the rate of respiration and the rate of ethylene production in comparison to the control and fruit treated with 0.5% chitosan + 10 mM vanillin. Furthermore, ascorbic acid content and the antioxidant properties of tomato were retained while shelf life was prolonged to 25 days without any negative effects on fruit postharvest quality.

Effect of pulsed light on postharvest disease control-related metabolomic variation in melon (Cucumis melo) artificially inoculated with Fusarium pallidoroseum

Pulsed light, as a postharvest technology, is an alternative to traditional fungicides, and can be used on a wide variety of fruit and vegetables for sanitization or pathogen control. In addition to these applications, other effects also are detected in vegetal cells, including changes in metabolism and secondary metabolite production, which directly affect disease control response mechanisms. This study aimed to evaluate pulsed ultraviolet light in controlling postharvest rot, caused by Fusarium pallidoroseum in 'Spanish' melon, in natura, and its implications in disease control as a function of metabolomic variation to fungicidal or fungistatic effects. The dose of pulsed light (PL) that inhibited F. pallidoroseum growth in melons (Cucumis melo var. Spanish) was 9 KJ m-2. Ultra-performance liquid chromatography (UPLC) coupled to a quadrupole-time-of-flight (QTOF) mass analyzer identified 12 compounds based on tandem mass spectrometry (MS/MS) fragmentation patterns. Chemometric analysis by Principal Components Analysis (PCA) and Orthogonal Partial Least Squared Discriminant Analysis (OPLS-DA) and corresponding S-Plot were used to evaluate the changes in fruit metabolism. PL technology provided protection against postharvest disease in melons, directly inhibiting the growth of F. pallidoroseum through the upregulation of specific fruit biomarkers such as pipecolic acid (11), saponarin (7), and orientin (3), which acted as major markers for the defense system against pathogens. PL can thus be proposed as a postharvest technology to prevent chemical fungicides and may be applied to reduce the decay of melon quality during its export and storage.

Ghazali H. Potential of UVC germicidal irradiation in suppressing crown rot disease, retaining postharvest quality and antioxidant capacity of Musa AAA "Berangan" during fruit ripening

Crown rot caused by fungal pathogen is the most prevalent postharvest disease in banana fruit that results significant economic losses during transportation, storage, and ripening period. Antifungal effects of ultraviolet C (UVC) irradiation at doses varied from 0.01 to 0.30 kJ m-2 were investigated in controlling postharvest crown rot disease, maintenance of fruit quality, and the effects on antioxidant capacity of Berangan banana fruit during ripening days at 25 ± 2°C and 85% RH. Fruits irradiated with 0.30 kJ m-2 exhibited the highest (i.e., 62.51%) reduction in disease severity. However, the application of UVC at all doses caused significant browning damages on fruit peel except the dose of 0.01 kJ m-2. This dose synergistically reduced 46.25% development of postharvest crown and did not give adverse effects on respiration rate, ethylene production, weight loss, firmness, color changes, soluble solids concentration, titratable acidity, and pH in banana as compared to the other treatments and control. Meanwhile, the dose also enhanced a significant higher level of total phenolic content, FRAP, and DPPH values than in control fruits indicating the beneficial impact of UVC in fruit nutritional quality. The results of scanning electron micrographs confirmed that UVC irradiation retarded the losses of wall compartments, thereby maintained the cell wall integrity in the crown tissue of banana fruit. The results suggest that using 0.01 kJ m-2 UVC irradiation dose as postharvest physical treatment, the crown rot disease has potential to be controlled effectively together with maintaining quality and antioxidant of banana fruit.