Enhancement of Coloration of “Satohnishiki” Sweet Cherry Fruit by Postharvest Irradiation with Ultraviolet Rays

Abstract

Enhancing coloration of fruit of lightly pigmented sweet cherry fruit (Prunus avium L. cv. “Satohnishiki”) was attempted by postharvest irradiation with UV rays. UV rays irradiation at 2.35 W m^-2 alone markedly promoted red color development and increased the anthocyanin content in the skin within 48 h. No additional effect was found when white light was combined with UV. The red color development proceeded even in the dark after UV irradiation, although the degree of coloration depended on the duration of the irradiation. By lowering the temperature during irradiation, from 23 to 11°C, the effectiveness of UV irradiation was suppressed. The weight loss of the fruit during irradiation increased with the intensity of irradiation, while it decreased at lower temperatures. The soluble solids content or firmness of skin and flesh were not appreciably affected.