RESUMO
Broccoli contains a high content of nutraceutical compounds, such as glucosinolates and flavonoids. In this work, the effect of different treatments that modulate postharvest senescence of broccoli was evaluated and flavonoid metabolism during postharvest storage was analyzed at 20°C. A decrease in hue angle (HUE°) and chlorophylls and an increase in flavonoid content were detected during senescence. It observed that most of the treatments that delayed senescence also decreased flavonoid content, except visible light and UV-C treatments. In all cases, a direct correlation between those treatments that increased flavonoid biosynthesis and BoPAL gene expression was detected. This response was not detected in the expression of the other two flavonoid synthesis relevant genes BoCHS and BoCHI, suggesting that BoPAL has a greater influence on the regulation of the via, during broccoli senescence. PRACTICAL APPLICATIONS: Broccoli is a vegetable with valuable nutritional properties. Because it is in full development at the time of harvest, it has a short shelf life. In this work, it is showed that visible light and UV-C treatments not only delayed the senescence of broccoli, but also increased flavonoid content. Our results suggest that the most important enzyme in the phenylpropanoid biosynthesis pathway during broccoli postharvest is phenylalanine ammonia lyase, and that this may be a key point in regulating the biosynthesis of these nutritionally valuable compounds.
Assuntos
Brassica , Aciltransferases , Brassica/genética , Brassica/metabolismo , Flavonoides/metabolismo , Liases Intramoleculares , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismoRESUMO
BACKGROUND: Chlorophyll is the most abundant pigment on Earth, essential for the capture of light energy during photosynthesis. During senescence, chlorophyll degradation is highly regulated in order to diminish toxicity of the free chlorophyll molecule due to its photoactivity. The first step in the chlorophyll degradation pathway is the conversion of chlorophyll b to chlorophyll a by means of two consecutive reactions catalyzed by enzymes coded by NYC1 (NON-YELLOW COLORING 1), NOL (NYC1-LIKE) and HCAR. RESULTS: In this work, we studied the expression of NOL and HCAR genes during postharvest senescence of broccoli. We found that the expression of BoNOL increase during the first days of storage and then decrease. In the case of BoHCAR, its expression is maintained during the first days and then it also diminishes. Additionally, the effect of different postharvest treatments on the expression of these genes was also analyzed. It was observed that the expression of BoNOL is lower in the treatments performed with 1-methylcyclopropene (1-MCP), 6-benzylaminopurine (6-BAP) and modified atmospheres, while BoHCAR expression showed an increase in these same treatments, and a decrease in the treatment with ethylene. There were no variations in the expression of both genes in heat treatment, UV-C treatment and visible light treatment. CONCLUSIONS: These results suggest that both BoHCAR and BoNOL show a lower regulation of their expression than other genes involved in chlorophyll degradation during senescence. © 2020 Society of Chemical Industry.
Assuntos
Brassica/enzimologia , Brassica/genética , Proteínas de Plantas/genética , Brassica/crescimento & desenvolvimento , Brassica/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismoRESUMO
Use of fungicides is a common practice as a postharvest treatment to control fruit decay. Nowadays, environment friendly technologies, such as heat treatments, are viable replacements. This study evaluated the effects of post-harvest heat treatments (traditional and microwave-assisted) on mandarins intentionally inoculated with Penicillium digitatum. For the studied heat treatments, the target temperature was 50 °C, which was held for 2.5 min. After heating, mandarins were cooled and stored at 25 °C for 13 days. MW treatments effectively prevented mold growth during storage, while HW only delayed it. Control mandarins (without treatment) showed the highest significant weight loss. Neither thermal treatment nor storage affected fruit juice pH (p > 0.05). Treated mandarins had a significantly lower vitamin C content than control fruits throughout storage, and all mandarins lost firmness by the 13th day (p < 0.05). Control and MW-treated mandarins had lower citric acid content; however, they retained color, total soluble solids (TSS) and had a higher maturity index. While HW mandarins did not have changes in citric acid content, they had higher TSS, and lower maturity index. MW-assisted treatments were effective at inactivating molds and helped retain some nutritional and physical-chemical characteristics of mandarins. However, juice of MW-treated mandarins was not preferred by judges in the sensory tests, the juice was rated lower than that obtained from the other treatment. Postharvest heat treatments may constitute a helpful application to control mandarin' fungal decay.
RESUMO
The use of vented clamshells has become popular in the packaging of grapes for local and international markets. The aim of this study is to evaluate the postharvest preservation of 'Benitaka' table grapes individually packaged in vented clamshells using different types of SO2-generating pads and perforated plastic liners during cold storage. A completely randomized design with four replications in a two-factor arrangement with an additional treatment [(4 × 3) + 1] was used. The trials were carried out under two situations: Artificial or natural infections with Botrytis cinerea, which is the causal agent of gray mold on table grapes. The incidence of gray mold, shattered berries, and stem browning were evaluated at 30 and 45 days of cold storage at 1 ± 1 °C and 3 days of shelf-life at 22 ± 1 °C after the period of cold storage. Mass loss and berry firmness were also examined at the end of the cold storage period. The use of dual-release SO2-generating pads containing 5 or 8 g of a.i. and slow-release pads with 7 g of a.i. was effective in controlling the incidence of gray mold in grapes packaged in vented clamshells and kept under cold storage for up to 45 days. Under these storage conditions, perforated plastic liners with 0.3% ventilation area or micro-perforated liners with 1.0% ventilation area reduced the percentage of mass loss and shattered berries.
RESUMO
In Guadeloupe, anthracnose of bananas, caused by Colletotrichum musae, is commonly controlled by postharvest thiabendazole treatments. A survey was conducted in 45 banana packing stations of Guadeloupe to determine the proportion of isolates that were resistant to thiabendazole. Isolates resistant to thiabendazole concentrations of 1 µg/ml (R1), 5 µg/ml (R5), and 50 µg/ml (R50) were detected. Most of the resistant isolates were R1 or R5, and of 1,350 isolates, the proportion of resistant isolates (R1 + R5 + R50) was 23%, ranging from 0 to 70% depending on the location. The presence of resistant isolates was correlated with the exclusive use of benomyl as foliar aerial sprays from 1972 to 1982 to control Sigatoka disease. Isolates resistant to concentrations of 1 and 5 µg/ml were as pathogenic as the susceptible isolates and were not controlled satisfactorily by postharvest thiabendazole treatments. Alternative control measures and the importance of resistance in terms of anthracnose control in Guadeloupe are discussed.