Levodopa Content in Different Parts of Broad Beans

Levodopa (L-dopa) in flowers, stems, leaves, bean pod, testa and cotyledon of different varieties of broad beans was determined by means of HPLC. Effect of drying temperature and bean’s floral color on the L-dopa content was studied. The results showed that the L-dopa content was highest in flowers and lowest in cotyledons, in the order of: flowers > leaves > pod > stem > testa > cotyledons. The L-dopa content in flowers ranged in the order of:white flowers > light violet flowers > purple flowers. The darker the floral color, the lower the L-dopa content became. The drying temperature affected significantly on the L-dopa content in the flowers. At 100℃, the L-dopa content of the dried flowers was only 60% of that in those dried at 40℃, indicating a significant L-dopa reduction due to the high temperature processing condition.