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Studies on the free sugars, water‐soluble gums and hemicelluloses from barley grains and malts
Author(s) -
Woolard Graham R.,
Rathbone Elner B.,
Novellie Lawrence
Publication year - 1977
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740280511
Subject(s) - xylose , hemicellulose , arabinose , chemistry , galactose , mannose , sugar , maltose , sucrose , polysaccharide , fructose , food science , biochemistry , free sugar , cellulose , fermentation
The free sugars, water‐soluble gums, and hemicelluloses have been isolated from four barley grain samples [ Hordeum vulgare (L.)], and from their commercial malts. Arabinose, xylose, galactose, glucose, fructose, maltose and sucrose occur as free sugars in the grains and the proportions of these sugars increase on malting. Mannose also occurs as a free sugar in the malts. The water‐soluble gums contain arabinose, xylose, lesser amounts of mannose and galactose, and varying amounts of glucose. The aqueous‐ethanol supernatants from the hot‐water extracts are glucans of low molecular weight. The hemicellulose A polymers contain arabinose, xylose, mannose and glucose. Wide variations in the mannose and glucose contents were observed in these polysaccharides. The hemicellulose B polymers are arabinoxylans, containing lesser amounts of galactose and glucose. The aqueous‐ethanol supernatants from the hemicellulose B precipitations contain arabinose, xylose, mannose, galactose and glucose. These polysaccharides differ markedly from those present in the aqueous‐ethanol supernatants of the hot‐water extracts. All polysaccharides are modified to varying degrees during malting.