RECOVERY OF PROTEIN-RICH BY-PRODUCTS FROM OAT STILLAGE AFTER ALCOHOL DISTILLATION

Ground oats, ground groats, and oat flour were fermented to ethanol. After ethanol was distilled, residual stillage was separated by screening and centrifugation into distillers’ grains, centrifuged solids, and stillage solubles. Oat distillers’ grains and centrifuged solids had crude protein contents (nitrogen X 5.83, dry basis) of 19 and 44%, respectively, and contained 67 and 5% of the total nitrogen of oats. Oat flour distillers’ grains and centrifuged solids had 43 and 48% protein, respectively, and accounted for 13 and 58% of the total nitrogen of oat flour. Of the nitrogen in oat stillage solubles, 54% passed through a 10K molecular weight cut-off membrane. Permeate from oat stillage solubles processed by combined ultrafiltration and reverse osmosis had much lower nitrogen, solids, and ash contents than did stillage solubles. This practical method to ferment ground oats and oat flour for ethanol and to recover valuable protein-rich byproducts may have commercial potential. © 1990, American Chemical Society. All rights reserved.