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Hui-juan Zhou, Xia-nan Zhang, Ming-shen Su, Ji-hong Du, Xiong-wei Li, and Zheng-wen Ye

quality ( Minas et al., 2018 ). Ultraviolet-C hormesis consists of the use of low doses of shortwave ultraviolet radiation with the objective of promoting desirable responses in living organisms ( Stevens et al., 2005 ), which could reduce the use of

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Junfang Wang, Yuxia Sun, Hengzhen Wang, Xueqiang Guan, and Lijun Wang

. Fig. 1. Schematic diagram of ultraviolet-C irradiation. Resveratol determination. According to the method of Liu et al. (2013) , each sample was extracted for 24 h in methanol and ethyl acetate (1/1, v/v; 1000 mg per 10 mL of organic solvent) (Beijing

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Ruixiang Yan, Joshua B. Gurtler, James P. Mattheis, and Xuetong Fan

. Ultraviolet-C radiation at short wavelengths (100–280 nm) has germicidal effects, resulting in damage to DNA ( Sinha and Häder, 2002 ). The U.S. Food and Drug Administration (FDA) has approved the use of ultraviolet light for disinfection of liquid (water and

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Guy D'hallewin, Mario Schirra, Enzo Manueddu, Antonio Piga, and Shimshon Ben-Yehoshua

`Washington Navel', `Biondo Comune', `Tarocco', and `Valencia Late' orange [Citrus sinensis (L.) Obsek] fruit, harvested at various periods of time, were subjected to ultraviolet-C (UV-C) irradiation at 0.5, 1.5, or 3.0 kJ·m-2 doses and then stored at 7 °C and 90% to 95% relative humidity (RH) for 4 weeks plus one additional week at 20 °C and 80% RH. Following UV-C treatment, there was varying amounts of rind browning and necrotic peel damage, depending on cultivar, treatment dose, and harvest date. `Tarocco' fruit were damaged more easily by UV-C treatment than the other cultivars. `Valencia L.' were the most resistant to UV-C irradiation, showing no adverse effects at the lowest dosage and having the lowest percentages of damaged fruit at higher dosages. `Washington Navel' and `Biondo Comune' oranges showed an intermediate susceptibility to UV-C treatment, with negligible differences between these cultivars. The percentage of damaged fruit after irradiation at the higher UV-C dosages decreased in most fruit samples as the season progressed. UV-C irradiation at 0.5 kJ·m-2 effectively reduced decay development compared with nontreated fruit. Irradiation with 1.5 kJ·m-2 was more effective compared with 0.5 kJ·m-2 only in early harvested fruit. In `Washington Navel' and `Biondo Comune' oranges in the later harvests, treatment with 3.0 kJ·m-2 improved decay control further, compared with 0.5 kJ·m-2. Following UV-C treatments the phytoalexins, scoparone and scopoletin, accumulated in flavedo tissue depending on the cultivar, fruit age, and UV-C treatment. Both phytoalexins displayed a similar accumulation pattern, however, the levels of scopoletin were very low compared with scoparone. Concentrations of phytoalexins rose as the irradiation dose increased. No scoparone and scopoletin could be detected in nontreated fruit. The highest concentration of phytoalexins among cultivars was recorded in `Valencia Late' oranges, the lowest in `Tarocco', with similar intermediate accumulations in `Washington Navel' and `Biondo Comune'. In `Washington Navel', `Biondo Comune', and `Tarocco' oranges, the rate of scoparone accumulation was significantly higher in fruit harvested earlier in the season while `Valencia late' oranges exhibited an opposite trend.

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M. Erkan, C.Y. Wang, and D.T. Krizek

Exposure of fresh-cut zucchini squash (Cucurbita pepo L., cv. Tigress) to ultraviolet-C (UV-C) irradiation for 1, 10, or 20 min significantly reduced microbial counts and severity of decay during subsequent storage at 5 or 10 °C. However, the respiration rate and ethylene production of the slices were not affected by the UV-C treatments. Slight UV-C damage (reddish brown discoloration) was detected on the surface of 10- and 20-min treated slices after 12 days of storage at 10 °C. Slices stored at 5 °C did not show UV-C damage. Chilling injury was not observed until after 20 days of storage at 5 °C. The symptoms of chilling injury appeared as dried sunken brown spots on the surface of cortex tissue. UV-C treatments did not affect the degree of chilling injury during storage at 5 C. The storage quality of fresh-cut zucchini squash was improved by UV-C exposure primarily because of the retardation of microbial growth and reduction of decay. The influence of UV-C irradiation on sugar and organic acid contents of the fresh-cut zucchini squash will also be discussed.

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Valtcho D. Zheljazkov, Charles L. Cantrell, M. Wayne Ebelhar, Christine Coker, and William B. Evans

purchased from Pacific Botanical, LLC (Grants Pass, OR) and analyzed in triplicate. Shoots from Baikal skullcap were not commercially available. High-performance liquid chromatography-grade solvents methanol (MeOH; ultraviolet c.o.205) and acetonitrile

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Xiuxiu Sun, Elizabeth Baldwin, Chris Ference, Jan Narciso, Anne Plotto, Mark Ritenour, Ken Harrison, Dave Gangemi, and Jinhe Bai

ultraviolet-C on the sensory properties of Romaine lettuce and kale and found the treatment provided better scores than the control. In addition, fresh-cut lettuce washed in a 3 mg·L −1 aqueous ClO 2 did not adversely affect sensory quality ( Lopez-Galvez et

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Kevin M. Folta and Sofia D. Carvalho

red wavelengths. Responses have been noted as far out as ultraviolet-C (260 nm; Hamner et al., 2009 ) and even into the near infra-red ( Johnson et al., 1996 ). Fig. 1. The relative distribution of electromagnetic energies and the wavelengths that

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Nathan J. Jahnke, John M. Dole, and H. David Shew

fungicide-resistant populations continue to grow ( Fillinger and Walker, 2016 ), other methods of control such as ultraviolet C pulses ( Darras et al., 2015 ) and increased secondary metabolite production like mannitol dehydrogenase have shown positive

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Zhi-Rong Li, Kang-Di Hu, Fen-Qin Zhang, Shi-Ping Li, Lan-Ying Hu, Yan-Hong Li, Song-Hua Wang, and Hua Zhang

( Li et al., 2014 ). To extend the shelf life of broccoli, various methods have been developed, including modified atmosphere packaging, ultraviolet-C and light irradiance, and appropriate refrigerated storage ( Chen et al., 2008 ). H 2 S has been shown