title: Amylose and amylopectin branch chain reactivity in a model derivatization system.
abstract: The impact of starch granule structure on amylose (AM) and amylopectin (AP) chain reactivities was investigated over a 24h period in a model reaction system utilizing a fluorescent probe [DTAF, 5-(4,6-dichlorotriazinyl)aminofluorescein] as a reagent. For various reaction time intervals (0.5, 4, 12, or 24h), molecular reactivities of debranched starch derivatives were assessed via size-exclusion chromatography equipped with refractive index and fluorescence detection. For all starch chain fractions, the initial rate of derivatization (0-0.5h) was rapid, but decreased thereafter. Starch chain reactivities followed the general order: AP long chains ≫ AM, AP medium chains>AP short chains, though both AM and AP long chain reactivities were somewhat impacted by the high relative reactivity of starch chains eluting in the AM/AP long chain boundary region. Varied starch chain reactivities were attributed to their relative locale within the granule, corroborating the impact of granule architecture on molecular-level reaction patterns of starch chains.
authors.affiliation: School of Food Science, University of Idaho, PO Box 442312, Moscow, ID 83844-2312, USA.
authors.forename: Jung Sun
authors.initials: JS
authors.lastname: Hong
authors.affiliation: School of Food Science, University of Idaho, PO Box 442312, Moscow, ID 83844-2312, USA. Electronic address: huberk@byui.edu.
authors.forename: Kerry C
authors.initials: KC
authors.lastname: Huber
mesh_terms: D000687:Amylopectin / Q000737:chemistry*; D000688:Amylose / Q000737:chemistry*; D002850:Chromatography, Gel; D005456:Fluorescent Dyes / Q000737:chemistry*; D015394:Molecular Structure; D013213:Starch / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D005456:Fluorescent Dyes; D013213:Starch; D000688:Amylose; D000687:Amylopectin
keywords: Chemical modification; Fluorescent probe; Granule; Modified starch; Reaction kinetics; Wheat starch