Irradiation of fruit and vegetables can potentially be used by industry as a quarantine method to contain insect pests, microorganisms, and to extend shelf life. Gamma, electron beam, and ultraviolet radiation are the most frequently used radiation techniques. These radiation treatments have an effect on bioactive compounds. Grapefruit juice contains bioactive compounds such as limonoids, flavonoids, and furocoumarins. Bioactive furocoumarins in grapefruit juice have been found to increase the bioavailability of many drugs. Bergamottin, dihydroxybergamottin, and paradisin A are major furocoumarins that are shown to inhibit the activity of CYP P450 3A4 and P-gylcoprotein, which are involved in the first pass metabolism of drugs in the gut. This results in a dose-dependent increase of the drug beyond what is intended. Furocoumarins are photoreactive compounds and will readily react to ultraviolet radiation. The effect of various doses of ultraviolet radiation was investigated on `Rio Red' and `Marsh White' grapefruit. Grapefruit juice (50 mL) was irradiated with Ultraviolet A, B, and C radiation for either 5 or 10 min. Treated and control juice was extracted with 100, 50, and 50 mL of ethyl acetate. The extract was then dried and reconstituted with methanol and filtered through a 0.4-μm PTFE membrane filter. The methanol extracts were analyzed by HPLC and the concentrations of bergamottin, dihydroxybergamottin, and paradisin A were compared for UVA, UVB, UVC, and control. This project is based upon work supported by the USDA-CSREES under Agreement USDA IFAFS # 2001 52102 02294 and USDA # 2005-34402-14401 “Designing Foods for Health” through the Vegetable & Fruit Improvement Center.
vitro by yellow filters Amer. J. Potato Res. 75 219 224 Sorauer, P. 1899 Uber intumescenzen. Ber. d Deutsch. Bot. Ges. 17 456 460 Springer 1978 Plants and near-ultraviolet radiation New York Botanical Garden Press 44 1 127 Trotter, A. 1904 Intumeszenze
In order to determine whether the concentration of floral petal anthocyanin pigments could be increased, ultraviolet radiations in the UV-A and UV-B wavelength bands were presented to a variety of flowering plants to partly restore those wavelengths filtered out by greenhouse glass. In no tested plant did the supplementary ultraviolet radiation enhance floral anthocyanin content. Supplementary UV radiation has no economic value in greenhouse production of flowering plants.
Near ultraviolet radiation appears to be largely responsible for solar injury (SI) and vein tract browning (VTB) of cantaloupes (Cumis melo L., Reticulatus group, cv. PMR 45) grown under field conditions in the San Joaquin Valley of California. Incidence and severity of SI were substantially reduced when near UV flux impinging on the fruits at solar noon was reduced to 21 Wm-2 or less and especially when wavelengths below 320 nm were excluded by the use of plastic UV filters. VTB was reduced when UV flux was 12 Wm-2 or less or when wavelengths below 320 nm were excluded. In cantaloupes, near UV appears to directly induce SI but to indirectly induce VTB, a postharvest disorder, by accelerating aging of surface tissues.
, and ultraviolet radiation ( Glenn et al., 2002 , 2008 ; Steiman et al., 2007 ). Reflection of IR can reduce canopy temperature as much as 5 °C, which will reduce potential transpiration ( Glenn, 2009 ; Glenn et al., 2003 ; Jifon and Syvertsen, 2003
A disorder of red raspberry (Rubus idaeus L.) in an area exposed to high temperature and solar radiation has been identified as a form of solar injury. Specific fruit maturity stages were defined and susceptibility to injury was found to rapidly increase as fruit matured from the “green” to the “white” to the “pink” stage. Appreciable injury (more than two unpigmented drupelets per fruit) only occurred at 42C and higher with 4 or more hours of UV radiation at the fluence level used. While the injury at 42C was proportional to UV exposure, the radiation environment in the laboratory was not designed to simulate solar radiation. Therefore, no quantitative function relating injury to fruit temperature and UV radiation is presented. The results indicated that attenuating UV absorption alone, without lowering temperature, is likely to protect raspberries in the field.
L. exposed to ultraviolet-B radiation Plant Physiol. 60 165 169 Caldwell, M.M. 1971 Solar ultraviolet radiation and the growth and development of higher plants, p. 131–177. In: A.C. Giese (ed.). Photophysiology Academic Press, New York, NY Cen, Y
powdery mildew control, and insecticides reduced the severity of T3B when such applications were made before periods of T3B occurrence. Because such pesticide materials contain lignins that protect chemicals against solar and ultraviolet radiation, we
Three trials, beginning June, July, and September 1991, examined the breakdown of photodegradable plastic bags. The plastic contained a light-sensitive compound dissolved in the polymer to hasten degradation. The bags were placed in east-west rows on bare ground. Other factors studied included turning the bags over either every 3 or 7 days and either filling the bags with fresh grass clippings or leaving them empty. Strength loss was determined with a hand-held puncture tester. Strength increased initially by 36%, 32%, and 63% in the three trials, respectively. The bags took 33, 35, and 64 days to reach brittleness (puncture strength of 180 g) in the three trials, respectively. Once degradation began, all trials showed similar rates of decline. However, the degradation began 7 days after exposure in the first two trials, but not until 14 days after exposure in the September trial. The addition of grass clippings to the bags increased the initial strength and delayed the onset of degradation. Turning the bags every 3 days rather than every 7 did not affect degradation.
‘Honey Dew’ melon fruits (Cucumis melo L.) matured under filters that transmitted between 1% and 100% of total solar and between 2% and 100% of ultraviolet (UV) radiation. Solar yellowing (SY) developed predominantly on top of the melons and increased as their exposure to direct solar radiation increased. Degree of exposure to solar radiation during maturation and susceptibility to postharvest development of chilling injury (Cl) during 17 days at 2.5°C were inversely related. SY and Cl also were inversely related. Levels of ACC in the skin were low at harvest and unaffected by degree of exposure to solar radiation. Reducing the exposure to the sun by half nearly doubled the concentration of ACC during chilling; complete shading resulted in little additional increase in ACC. After chilling, the skin from the bottom of the melons consistently contained slightly more ACC than that from the top. Chemical name used: 1-aminocyclopropane-1-carboxylic acid (ACC).