1976 年 23 巻 1 号 p. 59-66
Potato starch has been known for its high phosphorus content, which is mainly bound to C6 of glucose residue of amylopectin. Substitution of cations bound to the phosphate was carried out for the purpose of changing the physical properties of potato starch. Mother starch was substituted by hydrogen-, potassium-, sodium- and calcium ions, then physical properties were determined by means of photopastegraphy, amylography, swelling powers, solubility and stability for cold temperature storage. Potato starch showed higher viscosity by increase of alkali metal substitution, and on the other hand, by the introduction of alkaline earth metal, potato starch showed a typical two step swelling pattern and lower viscosity by amylography and increased paste stability against mechanical shearing. Cation substitutions are especially interested for high phosphate potato starch, which contains 90-110 mg naturally bound phosphorus per 100 g of starch, as food processing starch without any chemical modification such as esterification or etherificaton. Phi sical properties of the substituted starch were varied by the balance of alkali metal ions and alkaline earth metal ions. For the mechanism of the swelling inhibitions of potato starch by calcium-, magnesium ion substitution, we speculate that about two third of existing phosphate were cross-linked between two chains through an ionic bond of calcium or magnesium.