Abstract
The difference in carotenoid components among various color types of soybean seeds, and the changes in carotenoid composition during seed development were examined by reverse-phase high-performance liquid chromatogrphy (HPLC). Lutein was the major carotenoid component in seed extracts from the common yellow soybean and from a variety having a black seed coat. Green soybean seeds contained several xanthophylls in addition to lutein. None of the mature soybean seeds contained β-carotene, a part from a trace amount being detected in a local variety of green soybean. The total carotenoid and lutein contents were higher in green soybeans than in the yellow types, and the estimated total amount of carotenoids correlates with that of chlorophylls. The thylakoid membrane residue in the plastids of green soybean had lost its functional lamella structure. Immature soybean seeds contained a green-vegetable type of carotenoids including α- and β-carotene. The amount of β-carotene decreased more rapidly than that of lutein and chlorophylls during seeds maturation. These results suggest that β-carotene, which acts as a photoprotective agent in developing seeds, is susceptible to degradation in the course of seed maturation.
