Properties of aqueous dispersions of amylose–sodium palmitate complexes prepared by steam jet cooking

Aqueous dispersions of high-amylose corn starch were steam jet cooked and blended with aqueous solutions of sodium palmitate to form amylose inclusion complexes for investigation of their bulk properties. The rheological properties of the cooled dispersions depended on the starch concentration and varied from low-viscosity liquids (at 3.75% and 5.00% solids) to gels (at 6.64% solids). Gel formation was not caused by the formation of permanent cross-links. Viscosities of the dispersions increased when they were acidified with 0.02N HCl, and at pH 3.6, about 90% of the dispersed solid precipitated from the aqueous dispersion, due to conversion of complexed sodium palmitate into insoluble palmitic acid. Addition of sodium chloride solution also increased the viscosities of jet-cooked dispersions, and caused the amylose complexes to precipitate. The gelling properties of these preparations suggest practical applications as dispersants for lipids in foods, lotions, and water-based lubricants.