STUDIES ON THE FREE SUGARS OF THE BARLEY GRAIN V. COMPARISON OF SUGARS AND FRUCTOSANS WITH THOSE OF OTHER CEREALS

Open Access
Publisher Website
Google Scholar
Abstract
Ripe intact grains of rye, wheat and barley are rich in fructosan and in glucodi-fructose, oats may contain moderate amounts of these carbohydrates, but maize contains neither. Fructosan content runs parallel with the content of water-soluble gum-like pentosans, so that the amounts of each decrease in the order: rye, wheat, barley, oats, maize. Moreover, the fructosan-rich and pentosan-rich cereals are those which contain abundant β-amylase in the raw grain. Taxonomic relationships of these aspects of parallel distribution of apparently unrelated materials are discussed, and it is suggested that the composition of the ripe grain depends on the degree of development along particular paths reached at the stage adjudged to represent ripeness, development differing to a major extent from one cereal to another and to a minor extent between samples of the same cereal, but depending also in some measure on post-harvest changes. Cereal adjuncts used for brewing contribute types and amounts of carbohydrates which depend on the nature of the raw cereal and on whether whole grain or separated endosperm is used in preparing the adjunct. Implications of the possible contribution of raffinose by certain adjuncts are discussed.