Fractionation and Characterization of Dent Corn and Amylomaize Starch Granules

Starch granules of dent corn and Classes V and VII amylomaizes were fractionated according to size by an aqueous differential sedimentation procedure. The sized fractions were characterized by microscopy and by a modified method for determining their iodine binding capacities. Results show an inverse relationship between granule size and iodine binding capacity in the amylomaizes. Ordinary dent corn does not show this. The percent apparent amylose in the fractions of amylomaize V starch amounted to 40% for the largest size particles and 52% for the smallest ones; for amylomaize VII starch, 46% for the large particles and 70% for the small particles. Dent corn averaged 23% apparent amylose.