title: Hydration properties and phosphorous speciation in native, gelatinized and enzymatically modified potato starch analyzed by solid-state MAS NMR.
abstract: Hydration of granular, gelatinized and molecularly modified states of potato starch in terms of molecular mobility were analyzed by (13)C and (31)P solid-state MAS NMR. Gelatinization (GEL) tremendously reduced the immobile fraction compared to native (NA) starch granules. This effect was enhanced by enzyme-assisted catalytic branching with branching enzyme (BE) or combined BE and β-amylase (BB) catalyzed exo-hydrolysis. Carbons of the glycosidic α-1,6 linkages required high hydration rates before adopting uniform chemical shifts indicating solid-state disorder and poor water accessibility. Comparative analysis of wheat and waxy maize starches demonstrated that starches were similar upon gelatinization independent of botanical origin and that the torsion angles of the glycosidic linkages were averages of the crystalline A and B type structures. In starch suspension phosphorous in immobile regions was only observed in NA starch. Moreover phosphorous was observed in a minor pH-insensitive form and as major phosphate in hydrated GEL and BE starches.
authors.affiliation: Department of Food Science, University of Copenhagen, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark. fhl@life.ku.dk
authors.forename: Flemming H
authors.initials: FH
authors.lastname: Larsen
authors.forename: Mirosław M
authors.initials: MM
authors.lastname: Kasprzak
authors.forename: Helle N
authors.initials: HN
authors.lastname: Lærke
authors.forename: Knud Erik B
authors.initials: KE
authors.lastname: Knudsen
authors.forename: Sven
authors.initials: S
authors.lastname: Pedersen
authors.forename: Anne S
authors.initials: AS
authors.lastname: Jørgensen
authors.forename: Andreas
authors.initials: A
authors.lastname: Blennow
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000378:metabolism*; D002850:Chromatography, Gel; D003460:Crystallization; D005782:Gels / Q000737:chemistry; D006027:Glycosides / Q000378:metabolism; D057446:Hydrodynamics; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D010758:Phosphorus / Q000302:isolation & purification*; D012542:Scattering, Radiation; D011198:Solanum tuberosum / Q000378:metabolism*; D013213:Starch / Q000737:chemistry / Q000378:metabolism*; D054159:Torsion, Mechanical; D014908:Triticum / Q000737:chemistry; D014783:Viscosity; D014867:Water / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry; D001614:beta-Amylase / Q000378:metabolism*
chemical_list: D005782:Gels; D006027:Glycosides; D014867:Water; D010758:Phosphorus; D013213:Starch; D015061:1,4-alpha-Glucan Branching Enzyme; D001614:beta-Amylase
keywords: Branching enzyme; HPSEC; Hydration; Solid-state NMR; Starch; β-Amylase