Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Record number 332699
Title Molecular breakdown of corn starch by thermal and mechanical effects
Author(s) Einde, R.M. van den; Akkermans, C.; Goot, A.J. van der; Boom, R.M.
Source Carbohydrate Polymers 56 (2004)4. - ISSN 0144-8617 - p. 415 - 422.
Department(s) Food Process Engineering
Publication type Refereed Article in a scientific journal
Publication year 2004
Keyword(s) twin-screw extrusion - waxy maize starch - weight degradation - amylopectin - depolymerization - fractions - rheology
Abstract The molecular weight reduction of corn starch at 30-43% moisture during thermal treatment at temperatures 90-160degreesC and during well-defined thermomechanical treatment at temperatures 90-140degreesC was investigated. Thermal treatment resulted, during the first 5 min in a decrease in molecular weight as measured by intrinsic viscosity, after which longer heating had no significant effect. Higher moisture contents and temperatures generally resulted in more breakdown, although the effect diminished at higher temperatures. The decrease in intrinsic viscosity during thermomechanical treatment at relatively low temperatures and moisture contents was shown to be only dependent on the maximal shear stress. At higher temperatures, thermomechanical breakdown could be split into a mechanical part depending on maximal shear stress and a thermal breakdown part, which was again time-dependent on the shorter time-scales only. Higher moisture content during thermomechanical treatment resulted in more thermal breakdown and lowered the shear stresses required for mechanical breakdown. Consequences for process design are discussed briefly. (C) 2004 Elsevier Ltd. All rights reserved.
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