EFFECT OF SURFACTANTS ON STARCH IN A MODEL SYSTEM

Molecular conformation of amylose in the presence of surfactants was studied. The intrinsic viscosity of neutral, aqueous salt amylose solutions decreased slightly, indicating that surfactants enter into the helical cavity of amylose molecules. Helical conformation of amylose is the most important factor in binding surfactants by starch. The amylose‐surfacant complex seriously impedes β‐amylolytic degradation of amylose. It was demonstrated by thin‐layer chromatography that amylose‐surfactant complexes were mainly responsible for the decreased maltose production. Studies of iodine‐staining properties, potentiometric titration, and β‐amylolysis showed that the loss of blue color results from surfactants occupying some of the helical cavity of amylose molecule that otherwise would be filled by iodine. The degree of insolubility of amylose‐surfactant complex in water varied from one surfactants to another. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim