제주단지무와 관동여름무의 생육시기별 유용성분 변화

Abstract

Functional metabolites were screened in native species of radish at different growth stages to broaden consumer market. Both Danji radish and Gwandongsummer radish were harvested periodically in 80, 100, 120, 150 and 180 days after sowing. Their roots and leaves were investigated for ally isothiocyanate(AITC), sulforaphane, total polyphenol compounds(TPC), total flavonoid compounds(TFC), minerals, antioxidative activity, myrosinase activity, and antibacterial activity. Danji radish produced 2~5 fold more leaves than Gwandongsummer radish. The highest amount of leaves 902 g/radish was obtained at 100 days' cultivation. The contents of AITC showed differences according to harvest time and species. The maximum levels were 0.94mg/g in roots of Danji radish and 1.02mg/g in leaves of Danji radish harvested in 100 days after sowing. Meanwhile, Gwandongsummer radish that were harvested contained only 0.69mg/g in roots and 0.72mg/g in leaves. The contents of sulforaphane were also higher in Danji radish roots (12.6ppm) and leaves (7.31ppm) than in Gwandongsummer radish roots (6.46ppm) and leaves (6.34ppm). The enzyme myrosinase which catalyzes AITC production through hydrolysis of glucosinolate was detected 30~42 unit in leaves of Danji radish which was higher than 20~23 unit in leaves of Gwandongsummer radish. Above 300 ppm of both TPC and TFC were contained in radish leaves, and leaves had more TPC and TFC than roots. The leaves of Danji at 100 days' cultivation showed the highest contents. Macro-mineral contents in radish were K>Ca>Mg>P in descending order. Among those, potassium content with 2~4% was 10 times higher than that of any other mineral. Iron (Fe) out of four micro-elements(B, Zn, Fe and Cu) showed the richest content 498.70ppm in leaves of Danji radish, whereas leaves of Gwandongsummer radish had only 116.90ppm of iron. The antioxidative activity of radish was investigated indirectly by measuring radical-scavenging activity. The radical-scavenging activities of Danji radish were 42.32% for 2-diphenyl-1-picrylhydrazyl and 57.47% 2,2'-azino-bis3-ethylbenzenothiazolin-6-sulfonic acid, respectively, compared with Trolox. Extracts of radish showed considerable antibacterial activity. Among those the extract from Danji roots had the strongest activity. This study suggests that Danji radish is more valuable and suitable as leave sources than Gwandongsummer radish, and it has high potential as functional food material.