Wheat classification

U.S. Wheat Classification According to Properties and Gluten Functionality... 

Fine grinding and air classification make possible the production of some cake flour from hard wheat and some bread flour or high-protein fractions from soft wheat. AppHcation of the process theoretically frees the miller from dependence on different wheats, either hard or soft, that change each crop year. The problem is how to market the larger volume of low protein or starch fractions at prices adequate to justify the installation and operation of the special equipment (46). 

The Osborne classification, which dates from 1907, was updated at a symposium on gluten in 1996. Gianibelli el al. point out that at least 1300 peptides can be obtained from wheat endosperm proteins after disulfide bond rupture using two-dimensional fractionation.6... 

There is another type of gluten available and that is produced in France by air classifying wheat flour. Air classification works by separating materials in an air stream on the basis of density. This air classified gluten has not been wetted and dried and behaves more like the gluten found in flour. 

Typical Results. Using the National Association of British and Irish Millers (NABIM) classifications, typical results for flour milled from British wheat varieties are shown below in Figures 1 -4 and Table 1. 

Table 1 Typical results obtained with a Chopin Alveograph for flour milled from British wheat varieties (see text for NABIM group classifications )...

Air buoyancy, effect on weighing, 26 242 Air classification, of wheat flour, 26 282 Air cleaners, to improve indoor air quality, 1 820, 831-834... 

Konopka, I., Fornal, L., Dziuba, M., Czaplicki, S., Nalgcz, D. 2007. Composition of proteins in wheat grain streams obtained by sieve classification. J Sci Food Agric 87 2198-2206. 

Morioka, Japan Rapid classification of partial waxy and waxy wheats was developed using PCR-based markers 267... 

The quantity of barley starch produced around the world is very little when compared to starch production from corn, wheat, rice, potato or tapioca. There are only a few processing plants around the world that produce starch concentrate or purified starch from barley. Barley starch concentrates containing up to —78% (dry basis) starch are now produced in North America by milling and air-classification of barley grains. Milling disintegrates the grain into fine particles and air-classification separates them on the basis of differences in density, mass and projected area in the direction of air... 

High-speed hammer or pin mills result in some selective grinding. Such mills combined with air classification can produce fractions with controlled protein content. Flour with different protein content is needed for the baking of breads and cakes these types of flour were formerly available only by selection of the type of wheat, which is limited by growing conditions prevaihng in particular locations [Wichser, Milling, 3(5), 123-125 (1958)]. 

Classification.—Commercial starches are classified, according to the viscosity of the paste produced, as thick- or thin-boiling. Wheat starch is a typical thin-boiling starch, as a 5% mixture of wheat starch in water yields a thin, translucent syrup, scarcely gelatinous at boiling temperature. Corn starch, on the other hand, is a characteristic thick-boiling starch. Its 5% mixture with boiling water is practically non-fluid. 

Great diversity is shown by the varieties of wheat grown in the United States. More than 200 distinct varieties are grown. Clark ( Classification of American Wheat Varieties U. S. Department of Agriculture, Dept. Bull. 1074, 1922) divides American grown wheats into the following groups ... 

Figure 13.3 The classification and nomenclature of wheat gluten proteins separated by SDS-PAGE.

Shewry PR, Tatham AS, Forde J, Kreis M, Miflin BJ (1986). The classification and nomenclature of wheat gluten proteins a reassessment. J. Cereal ScL, 4 97-106. 

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