Starch is the carbohydrate present in the greatest amount in the mature wheat kernel; in fact, it exceeds all other types of compounds, being several times larger than the next largest class of substances.
It is formed out of carbon dioxide and water by the process of photosynthesis and is deposited in plant cells as macroscopic particles of varying size and conformation.
Many genes are involved in determining the shape, crystalline pattern and chemical properties of starch granules. Developments in the carbohydrate field are too numerous to be dealt with here, but the starch-protein matrix and the size of the starch granule in the wheat kernel are important considerations in flour milling and bakery processes.
S
tarch is the polymer of D-glucose, most of the hexose units being joined together by alpha-(1-4) bonds. They are varying properties of amylose and amylopectin, the former being virtually a straight chain, but with a few branch points, while the latter contains numerous side chains attached by 4 to 5% alpha-(1-6)-D-glucosidic linkages .The starch granules grow in the developing endosperm as single entities in amyloplasts. In wheat starch, they have a bimodal size distribution, with about 3 to 4 % being lenticular and 15 to 40 microns in size and the remainder being small, approximately spherical, granules ranging in size from about 1 to 10 microns.
Polysaccharides other than starch are found in cell walls of the parenchymatous and lignified of the wheat plant.
In the cell walls parenchymatous tissues, they are mainly the arabinoxylans and the soluble Beta-D-glucans.
Carbohydrates in Wheat
