title: Reversible thermal transition of soluble branched chains from slightly acid-treated potato starch.
abstract: The reversible thermal transition of soluble branched starch chains prepared from slightly acid-treated potato starch granules (ATS) was investigated. Potato starch was immersed in 15% sulfuric acid to obtain ATS with a 1% hydrolysis rate. About half of the molecules of ATS, which spontaneously formed large aggregates with a mass of a few million daltons in aqueous solution, was fractionated and soluble branched starch chains with a relative molecular weight (Mr) of 8.91 x 10(4) were obtained. Structural analysis indicated that the soluble branched starch chains consisted of three unit chains with Mr 7,900 and 21 unit chains with Mr 2,700. DSC and FT-IR measurements showed that the soluble branched starch chains underwent a reversible thermal transition, which is considered to be a helix-coil transition, during heating and cooling, but a debranched sample and beta-limit dextrins showed substantially different thermal behavior, indicating the contribution of the ordered structure of the branched chains.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Japan. k-taka@cc.tuat.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Kondo
authors.forename: H
authors.initials: H
authors.lastname: Kuroiwa
authors.forename: Y
authors.initials: Y
authors.lastname: Yokote
authors.forename: M
authors.initials: M
authors.lastname: Hattori
mesh_terms: D000143:Acids; D002152:Calorimetry, Differential Scanning / Q000379:methods; D006361:Heating; D011198:Solanum tuberosum / Q000737:chemistry*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013213:Starch / Q000737:chemistry*
chemical_list: D000143:Acids; D013213:Starch