Air classification of flours of three legume species: Effect of starch granule size distribution

The effect of starch granule size distribution on separation behaviour of whole starchy grain legume flours during air classification was studied, using laboratory‐scale equipment and two varieties each of cowpea (Vigna unguiculata), faba bean (Vicia faba) and pigeonpea (Cajanus cajan). Cut points at a range of classifier settings were calculated from particle‐size analysis of the fines and coarse fractions using a Coulter counter. The whole flours varied considerably in starch granule size distribution between species and varieties. Cowpea, which contained a high proportion of small starch granules, yielded fines with a higher starch content and a greater dry weight yield than the other species studied.