Quality Maintenance of Postharvest Horticultural Crops by Stress Treatments and Approach for the Elucidation of Its Mechanism

Abstract

This review deals with the effectiveness and mechanism of stress treatments, such as heat and UV treatments (hot air, hot water, and UV-B), on the quality maintenance of postharvest green horticultural crops such as broccoli florets and green sour citrus fruits (lime, Nagato-yuzukichi, and yuzu), in which chlorophyll (Chl) degradation is a main factor in quality deterioration. Postharvest stress treatments effectively suppressed Chl degradation with senescence during storage. In broccoli florets and lime fruit, hydrogen peroxide, which is produced by postharvest stress treatments, could induce the activation of the ascorbate-glutathione (AsA-GSH) cycle, and enhancement of the AsA-GSH cycle might be involved in the suppression of senescence in such produce. The mechanism of peroxidase-mediated Chl degradation and the control of Chl-degrading enzymes by stress treatments were determined using broccoli florets and Nagato-yuzukichi fruit. Peroxidase oxidized phenolic compounds such as apigenin, naringin and p-coumaric acid, which have a hydroxyl group at the p-position, to form phenoxy radicals, and Chl a could be degraded by the formed phenoxy radicals to colorless low-molecularweight compounds. It was found that the cationic isoperoxidase related to Chl degradation, which is localized in the chloroplast, increased with senescence during storage and enhancement of the activity was effectually inhibited by stress treatments. In addition to peroxidase, the activities and gene expression of other Chl-degrading enzymes were controlled by stress treatments. Thus, stress treatments seem to be a useful method for controlling Chl degradation in stored green fruits and vegetables.

Effect of ozone on the activity of antioxidant and chlorophyll‐degrading enzymes during postharvest storage of coriander ( Coriandrum sativum L.)

“…(Costa, Civello, Chaves, & Martínez, 2002;Kunieda, Amano, & Shioi, 2005;Suzuki & Shioi, 2002). In the Chl catabolic pathway, pheide a is degraded to Chl catabolites by pheide a oxygenase (PaO) and red Chl catabolite reductase (Park et al, 2007;Yamauchi, 2013). The substrate of PPH is phein, and both phein a and b are catalyzed to produce phytol-free pigments and pheide a and b, respectively (Schelbert et al, 2009).…”

Cell wall metabolism of peaches and nectarines treated with UV‐B radiation: a biochemical and molecular approach

“…UV‐C is effective in increasing the antioxidant capacity of strawberries in the post‐harvest period, in controlling the yellowing of broccoli florets, and reducing the incidence of chilling injury in stored peaches and peppers . Treatments with low and ambient UV‐B radiation (less harmful for the user than UV‐C) inhibit the yellowing of stored green fruits and vegetables and increase the antioxidant content of the produce . Recently, it has been shown that post‐harvest UV‐B treatments can improve, at least in selected genotypes, both the health‐promoting potential and the aesthetic properties of tomato and peach fruits by increasing anthocyanin contents .…”

“…4,5 Treatments with low and ambient UV-B radiation (less harmful for the user than UV-C) inhibit the yellowing of stored green fruits and vegetables and increase the antioxidant content of the produce. 6,7 Recently, it has been shown that post-harvest UV-B treatments can improve, at least in selected genotypes, both the health-promoting potential and the aesthetic properties of tomato and peach fruits by increasing anthocyanin contents. 8,9 UV wavelengths may also affect other ripening-related parameters, such as firmness, which, in strawberries, is affected by changes in the UV wavelengths transmitted by polythene films in protected cultivation.…”

Salt Solution Treatments Trigger Antioxidant Defense Response against Gray Mold Disease in Table Grapes

“…It is well known that POD controls the availability of hydrogen peroxide in the cell wall, which is a requirement for the cross-linking of phenolic groups in response to various external stresses [ 48 ]. In addition, treatment with UV-A or UV-B increased the levels of antioxidants such as ascorbate, α-tocophol and polyphenol [ 49 ].…”