Structural features of amylomaize starch: Components of amylon 50 starch.

A commercial amylomaize starch, Amylon 50, was sub-fractionated with 1-butanol, and the two fractions (PF and SF) derived from the precipitate and supernatant fluid were characterized. The precipitated fraction (PF) was composed of amylose and amylomaize-specific amylopectin. An intermediate material was found in the supernatant fluid fraction (SF). Some characteristics of the intermediate material were consistent with those of a low-molecular-weight material previously isolated from amylomaize starch [T. BABA and Y. ARAI: Agric. Biol. Chem., 48, 1763-1775 (1984)]. The results of the present study, involving chromatographic separation with or without debranching treatment, demonstrate that Amylon 50 is composed of approximately 20% of amylose, 40% of amylomaize-specific amylopectin and 40% of the intermediate material.