Responses of phytonutrients and tissue condition in persimmon and cucumber to postharvest UV-C irradiation

• Published in: Postharvest biology and technology Vol. 145; pp. 33 - 40
• Main Authors: Imaizumi, Teppei, Yamauchi, Mizuha, Sekiya, Madoka, Shimonishi, Yutaro, Tanaka, Fumihiko
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2018; Elsevier BV
• Subjects: Ascorbic acid; Carotene; Chlorophyll; Cucumber; Cucumbers; Electrical impedance; Electrical impedance spectroscopy; Electrical properties; Equivalent circuits; Fruits; Functional ingredient; Ingredients; Irradiation; Nutrients; Nutrition; Parenchyma; Persimmon; Phytochemicals; Sterilization; Storage; Ultraviolet radiation; UV-C irradiation; β-Carotene; Functional ingredient; UV-C irradiation; Storage; Electrical impedance spectroscopy; Persimmon; Cucumber
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2018.06.003

•UV-C treatment was not effective for the enhancement of phytonutrients.•The surface of treated persimmon blackened due to tannin migration.•UV-C affected the brightness of cucumber peel.•UV-C decreased electrical cellular resistance in cucumber. Postharvest UV-C irradiation is expected to be a widely applicable sterilization technology for fruit and vegetables. In this study, the effects of UV-C irradiation on phytonutrients and tissue conditions in persimmon and cucumber were investigated. UV-C having a peak wavelength of 253.7 nm was irradiated on their surface (12.9 W m−2) for 0 to 15 min. The UV-C irradiation was not effective for the enhancement of phytonutrients (polyphenol, β-carotene, ascorbic acid, chlorophyll) in persimmon and cucumber. However, some responses of tissue condition to UV-C irradiation appeared. Some persimmon fruit became blackened during storage, and the transfer of tannin from the parenchyma to the epidermal tissue was observed in the fruit. We also evaluated the factors responsible for the color change in the fruits. In addition, electrical impedance was measured, and electrical properties were obtained by equivalent circuit analysis. These properties reflected the tissue conditions. In particular, the extracellular resistance of UV-C-irradiated cucumber exhibited clear differences from non-irradiated samples.