Varietal differences in free amino acid and sugar concentrations in immature seeds of soybean under raw and boiling treatments

Differences in the concentrations of free amino acid and sugar in immature seeds harvested 35 days after flowering of nine vegetable-type soybean (Edamame) and five grain-type soybean cultivars, and changes in the component of free amino acids and sugars in seeds after bioling for 3 min. were examined. The concentrations of total free amino acids largely varied among cultivars. The concentrations of the total free amino acids were highest in the seed of Shirayama-dadacha (11.0mg/gFW), and followed Sapporo-midori, Aobata and Kahori. On the free amino acids examined, major component in the immature seeds Shirayama-dadacha were glutamic acid, asparagine and alanine and the component of the these three amino acids were almost 50% per total amino acids. After boiling, avarage concentration of total free amino acids sharply decreased to 74%. The concentrations of the total sugar and sucrose were highest in the immature seeds of Shirayama-dadacha that contain 47 and 30 mg/ gFW, respectively. The concentrations of the total sugar and sucrose were also higher in vegetable type cultivars, Aobata and Hiden. After boiling of immature seeds, average concentration of total sugar elevated 1.5 hold, although the concentration of sucrose was unchanged. (Received Jul. 7, 2003 ; Accepted Dec. 30, 2003)