Variations in the soluble sugar and organic acid contents in radish (Raphanus sativus L.) cultivars

The radish is a root vegetable of the Brassicaceae family that is mainly consumed in Far Eastern Asian countries. Because chemical indexes indicating the quality of a radish have not been established, we investigated the variations in the contents of the soluble sugars and organic acids that influence taste among seven radish cultivars. In terms of the total soluble sugar content, which is a strong index of sweetness, Koshin, Kouto, and Shogoin were the three highest among the seven cultivars. Sobutori, which is the most common radish cultivar in Japan, was the lowest. The total organic acid contents varied among the seven cultivars, although they were five to thirteen times lower than the total soluble sugar contents. These results indicate that there are variations in the soluble sugar and organic acid contents among radish cultivars; therefore, these contents may be used as chemical indexes for the quality of radishes.