Air Classification

Air Classification. A process by which flour (q.v.) at the mill (q.v.) is separated, by means of air currents, generally into three fractions according to particle size and particle weight, with each fraction having different starch (q.v.) and protein (q.v.) contents. For example, a hard wheat straight flour (q.v.) will normally yield a fine fraction with a protein content as high as 25%, a medium fraction with a protein content as low as 5%, and a coarse fraction whose protein content approximates that of the original flour. Each fraction has different functional properties that render it suitable for different uses.