Effects of Oxygen Concentrations on the Occurrence of Internal Blue Discoloration in Japanese Radish (Raphanus sativus) Roots During Storage

Abstract

　The internal blue discoloration observed in Japanese radish (Raphanus sativus L.) roots is a physiological disorder that occurs several days after harvest. The incidence of this phenomenon has been shown to be temperature- and cultivar-dependent. In this study, we stored the susceptible cultivar 'Fukuhomare' under different packaging conditions, and investigated the relationship between gas concentrations and the occurrence of internal disorders, focusing on internal blue discoloration. At an ambient temperature of 20℃ with 21% oxygen, blue discoloration was observed after an approximate 5-day storage period. Under 7% oxygen, blue discoloration appeared after approximately 8 days of storage. It appears that by lowering oxygen concentrations, the occurrence of internal disorders, mainly internal discoloration, could be delayed. These results suggest that atmospheric oxygen concentrations affect the occurrence of blue pigmentation in radishes. In addition, low oxygen concentrations as a result of appropriate packaging are found to be effective in preventing the occurrence of internal blue discoloration in the Japanese radish.