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CHANGES IN THE FREE SUGAR CONTENT OF BARLEY KERNELS DURING MATURATION
Author(s) -
LaBerge D. E.,
MacGregor A. W.,
Meredith W. O. S.
Publication year - 1973
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1973.tb03568.x
Subject(s) - raffinose , dry matter , chemistry , sucrose , fructose , anthesis , ripeness , dry weight , sugar , food science , botany , biology , ripening , cultivar
The free sugars extracted from kernels of a two‐row barley variety, Betzes, were separated and determined quantitatively as negatively‐charged borate derivatives by anion‐exchange chromatography on substituted polystyrene resin. Sugars were determined at 2 or 3 day intervals immediately following anthesis, until kernels achieved harvest ripeness. Initially, the free sugars accounted for 6.5% of kernel dry matter; reducing sugars comprised 80% of the total free sugars, primarily as fructose (3% of the kernel dry matter) and glucose (2% of kernel dry weight), with lesser amounts of galactose, mannose, and maltose. Sucrose was the principal non‐reducing sugar (1.8% of the kernel dry weight), but traces of raffinose were also detected. As kernel dry matter increased, the relative amount of free sugars decreased rapidly and comprised 2% of the kernel dry matter in mature kernels. At harvest ripeness, non‐reducing sugars comprised 90% of the total free sugars. Sucrose decreased slightly from 1.8 to 1.2% of total kernel dry matter, but actually increased from 90 μg in immature kernels to 500 μg in mature kernels; raffinose increased relative to kernel dry matter from trace amounts 20 days after anthesis to 0.7% of kernel dry matter (i.e., 250 μg/kernel) 36 days after anthesis, and declined to 0.4% in mature kernels. Non‐reducing, soluble fructosans were present at all stages of kernel maturation, but were not determined quantitatively.