Preparation of granular cold-water-soluble starches by alcoholic-alkaline treatment

Granular cold-water-soluble starches were prepared by an alcoholic-alkaline treatment. Native starches were treated with mixtures of ethanol and NaOH solution to swell starch granules. The treated starches were then neutralized with HCl, washed, and dried at 80 o C for 3 hr. The method was effective with a wide variety of starches, including normal, high-amylose, and waxy starches. The efficacy of the method depended mainly on starch variety, concentration of ethanol and NaOH, and reaction temperature. Different reaction conditions gave products different properties. Lesser concentrations of ethanol, greater concentrations of NaOH, or higher reaction temperatures gave the resulting starches better cold-water solubility. The resulting starches displayed cold-water solubility of ∼70-90%. A trace amount of small molecules, mainly amylose, was leached out in the supernatant during the preparation. Total weight losses were ∼0.01, 0.4, and 1.9% for waxy maize, normal maize, and high-amylose maize starches, respectively