title: Effect of phytate-removal and deamidation of soybean proteins on calcium absorption in the in situ rats.
abstract: Soybean proteins were deamidated by cation-exchange resins after phytate, the inhibitor for calcium absorption from the small intestine, was removed in order to provide the enhancement function of calcium absorption to soybean proteins. About 92% of the phosphorus was removed from the soybean proteins by anion-exchange-resin treatment, indicating that most of the phytate was removed. About 70% of the acid amide was deamidated by cation-exchange-resin treatment, and phytate-removed and deamidated soybean proteins (PrDS) having high calcium binding properties were obtained. PrDS were hydrolyzed by digestive enzymes and their calcium-binding properties and the enhancement function of the calcium absorption from the small intestine of rats were examined. As a result, PrDS retained their high calcium binding properties even after hydrolysis by digestive enzymes. In situ experiments showed that PrDS and their hydrolysates enhanced the calcium absorption from the intestine.
authors.affiliation: Department of Agricultural and Biological Chemistry, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi 252-8510, Japan. kumagai@brs.nihon-u.ac.jp
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kumagai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Koizumi
authors.forename: Noriko
authors.initials: N
authors.lastname: Sato
authors.forename: Yukako
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Suda
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Sakurai
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kumagai
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D007408:Intestinal Absorption; D010833:Phytic Acid / Q000302:isolation & purification*; D051381:Rats; D030262:Soybean Proteins / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D030262:Soybean Proteins; D010833:Phytic Acid; D002118:Calcium