Quantitative Analysis of Carotenoids in Carrot Cultivars Produced in Korea

Carrots (Daucus carota L.) are consumed as an important dietary source of provitamin A including $\beta$ -carotene, $\alpha$ -carotene and lutein. An HPLC method was applied to determine the content of the carotenoid composition in carrot cutivars cultivated in Korea. HPLC analyses were carried out with five carrot cultivars (Socheon-5-chon, Hongsim-5-chon, Myeongju-5-chon, Seonhongbom-5-chon and Betarich) sown at April, 2007 and six cultivars (Yeoreum-5-chon, Hanyeoreum-5-chon, Sinheukjeon-5-chon, Bibariheukjeon, Manina and Betarich) sown at August of the same year. In general, the former varieties are not used for the sowing at summer because of their bolting (growth of floral axis). The former and the latter carrots were harvested after 110 and 96 days from seeding, respectively, and the carotenoids were extracted with acetone after freeze-drying. The amount of $\alpha$ -carotene ( $117.7{\sim}205.3\;{\mu}g/g{\cdot}DW$ ) was similar to that of $\beta$ -carotene ( $113.1{\sim}189.6\;{\mu}g/g{\cdot}DW$ ) for the carrot cultivars sown at spring, while the content ( $46.2{\sim}71.1\;{\mu}g/g{\cdot}DW$ ) was about a half of $\beta$ -carotene content ( $92.5{\sim}140.2\;{\mu}g/g{\cdot}DW$ ) for the latter cultivars. In addition, the average content of lutein ( $25.2\;{\mu}g/g{\cdot}DW$ ) in the former cultivars was eight times higher than that in the latter cultivars ( $3.1\;{\mu}g/g{\cdot}DW$ ). Among the spring cultivation types, Socheon-5-chon and Myeongju-5-chon showed higher amount of $\alpha$ -carotene and $\beta$ -carotene, while the higher amount was determined in Yeoreum-5-chon and Sinheukjeon-5-chon among the autumn cultivation types. Validation of the HPLC-DAD method showed good linearity ( $r^2$ > 0.997) of the three compounds analyzed in a wide concentration range ( $0.025{\sim}20\;{\mu}g/ml$ ). The R.S.D. values for intra-day and inter-day precision were less than 19.2% and the mean recovery of each compound was 85.4~104.7%.