A study of some carbohydrate relationships in the wheat plant and of wheat starch extracted from mottled and unmottled grain

Abstract

Sucrose is the dominant accumulated carbohydrate in the wheat plant until approximately 4 weeks before harvesting, when starch takes this position. Starch is the dominant carbohydrate in the grain. Total reducing sugars are never accumulated in large amounts in any portion of the plant. The mature mottled grain contains significantly more starch and less protein than the unmottled. The developing grain from an area known to produce mottled wheat is always higher in starch and lower in protein when compared with grain from an unmottled area. Irrespective of variety and whether the grain is mottled or not, starch extracted from the mature grain contains 22.4 per cent. amylose, and there appear to be no major differences between the starches extracted from the respective grains. It is probable that while the ratio of amylose to amylopectin is set by heredity, the molecular size of these components varies as starch is laid down in the developing grain.