Properties of the starch from Alocasia odora (Department of Agricultural Chemistry)

自生植物クワズイモの根茎部から, 澱粉を分離精製し, その諸性質を調べた。クワズイモ中の澱粉は, 季節によって変動した。夏季には根茎部に多量の澱粉を蓄積し, 新鮮物中3.1%, 乾物中62%の澱粉を含有した。クワズイモ澱粉中のアミロースとアミロペクチンの成分比は10対90であった。アミロペクチンのギ酸生成量による末端基定量やβ-アミラーゼ分解限度などの結果から, アミロペクチンの平均鎖長, 外部鎖長および内部鎖長は, それぞれ, 21∿22,12∿13および7∿9となり, クワズイモ澱粉中のアミロペクチン成分の構造は, もちとうもろこしアミロペクチン成分の分枝構造に近似しているものと思われた。Properties of starch isolated from stems of Alocasia odora were studied. Starch was accumulated in alocasia stems, especially in summer. The starch content based on a dried sample was 62% while that on a fresh sample was 3.1%. Alocasia starch was found to be only 10% of amylose and to be less than amylose contents of other plant starches. The β-amylolysis limit, using β-amylase from sweet potato, for alocasia amylopectin, was 48%. The values for average, internal and external chain lengths for alocasia amylopectin, on the basis of formic acid formation in periodate oxidation and of β-amylolysis limit, were 21-22,7-9 and 12-13,respectively, glucose units. These results suggested that in the branching structure the amylopectin of alocasia starch resembled that of glutinous corn starch