Premium
Studies on Chemical Modifications in Heat‐processed Starch and Wheat Flour
Author(s) -
Theander O.,
Westerlund E.
Publication year - 1987
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19870390306
Subject(s) - starch , chemistry , lignin , amylopectin , arabinoxylan , polysaccharide , fractionation , retrogradation (starch) , glucan , food science , maillard reaction , chromatography , organic chemistry , amylose
Abstract 1,6‐Anhydro‐β‐ D ‐glucopyranose (levoglucosan) and oligosaccharides with these end units were present in 80% aqueous ethanol extracts from heat‐processed starch and wheat flour. Evidence was adduced that the 1,6‐anhydro‐ D ‐glucose units react further with starch and starch fragmentation products by external trans‐glycosidation reactions to give branched structures, resistant to amylolytic enzymes. High performance liquid chromatography (HPLC), 13‐carbon nuclear magnetic resonance ( 13 C‐NMR) and gas‐liquid chromatography (GLC) were invaluable tools for fractionation, identification and quantification of 1,6‐anhydrosaccharides, respectively. The analytical dietary fibre value comprising non‐starch polysaccharides and Klason lignin, increased with the extent of oven‐heating and extrusion cooking of wheat flour. This increase seemed to originate from mainly three types of reactions, namely: (1) chemical modification of starch to enzyme‐resistant glucan structures by external transglycosidation, (2) polymers formed by the Maillard reaction and analysed as Klason lignin, and (3) strong retrogradation of part of the starch (“resistant starch”). Another effect was that the water soluble part of the arabinoxylan in wheat flour increased.