Changes in Quality and Antioxidant Enzyme Activities of Bunched and Topped Radish (Raphanus sativus L.) Plants during Storage at 5 or 10C

Abstract

AbstractQuality changes of bunched and topped radishes (Raphanus sativus L.) during postharvest storage were investigated. Bunched radish plants, topped roots and detached leaves were stored at 5 or 10C for 9 days. Yellowing and wilting of leaves during storage at 10C were the main visual quality deteriorations in bunched radishes. Leaf detachment reduced respiration and ethylene production rates and weight loss of roots, and resulted in lower ascorbic acid, antioxidant capacity and phenolic content especially during storage at 10C. Root color did not change during storage, with or without leaf detachment. Leaf color did not change at 5C, whereas lightness and chroma increased and hue angle decreased at 10C, with larger changes observed in detached leaves. H2O2 content as well as peroxidase, ascorbate peroxidase and catalase activities in the root tissue were unaffected by leaf detachment, but increased during storage especially at 10C after 9 days of storage.Practical ApplicationsRadishes are marketed with the leaves attached on the enlarged root, which is the edible part of the plant, or are topped so that leaves are removed from the root. Consumers prefer to purchase radishes with the leaves attached because their green color is an indication of freshness. In retail market, higher than recommended temperatures are often encountered, resulting in yellowing of leaves; therefore, plants are topped and only the root is distributed. However, the effects of storage temperature as well as the removal of leaves on nutritional compounds of the edible roots have not been investigated and need to be determined, because nutritional quality is of increasing interest to the consumers. This study provides information on the effect of temperature and leaves removal on metabolism and quality of radish plants during storage, which can be applicable to sustain the quality and increase commercial marketing of radishes.