Cereal Chem. 71:582-587   |  VIEW ARTICLE


Amylose-Lipid Complex Formation During Single-Screw Extrusion of Various Corn Starches.

S. Bhatnagar and M. A. Hanna. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

Commercial corn starches containing 0-70% amylose were extruded with and without various lipids (myristic, stearic, and behenic acids; monoglyceride Dimodan PV; and tristearin) in a single-screw laboratory extruder at 110 C, 110 rpm, 19% moisture, and 4% lipid. X-ray diffractograms, iodine-binding capacity, and iodine spectrum of the soluble fractions of the extrudates were determined. Additions of fatty acids and monoglyceride resulted in V-patterns in X-ray diffractograms and decreased iodine-binding capacity of the extruded starches, indicating formation of complexes between amylose and lipids. Maximum binding was observed for myristic acid and 70% amylose starch. No binding was observed with tristearin. Physico-chemical properties of starches (expansion ratio, water-soluble carbohydrates, and water-solubility index) decreased. Bulk density increased upon addition of complexing lipids before extrusion. These properties reached limiting values as the percentage of complexed amylose increased above 20, 15, and 10% for 25, 50, and 70% amylose starches, respectively.