Cereal Chem 58:144 - 148.  |  VIEW ARTICLE
Air Classification of Legumes. I. Separation Efficiency, Yield, and Composition of the Starch and Protein Fractions.

R. T. Tyler, C. G. Youngs, and F. W. Sosulski. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

Two samples of each of eight grain legumes (mung beans, green lentils, Great Northern beans, faba beans, field peas, navy beans, baby lima beans, and cowpeas) were mechanically dehulled, pin milled, and air classified into starch and protein concentrates. The starch fractions contained 58.0-76.1% starch and 7.7- 20.1% protein, whereas the protein fractions contained 49.3-75.1% protein and 0.0-4.6% starch. The starch fractions from the first classification were remilled and air classified, yielding starch fractions, containing 71.0-85.9% starch and 4.0-10.4% protein, and a second series of protein concentrates, containing 38.0- 68.2% protein and 0.4-16.6% starch. Values for starch separation efficiency and protein separation efficiency (PSE) were calculated for each legume. Differences in PSE among legumes were significant (P less than 0.05), but differences in starch separation efficiency were not. Mung beans exhibited the highest PSE (88.9%) and cowpeas the lowest (78.2%). The fat, ash, and crude fiber contents were similar in the corresponding fractions of the various legumes, with fat and ash showing a marked concentration in the protein fractions. On the basis of PSE and the protein contents of the two protein fractions, mung beans and lentils were the most suitable legumes for air classification, and lima beans and cowpeas were the least suitable.