Cereal Chem 64:244-247   |  VIEW ARTICLE

Recovery of Protein-Rich By-Products from Sweet Sorghum Grain Stillage After Alcohol Distillation.

Y. V. Wu. Copyright 1987 by the American Association of Cereal Chemists, Inc. 

Because of current interest in sweet sorghum for ethanol production, methods for efficient recovery and utilization of sweet sorghum grain stillage were investigated. Ground sweet sorghum grain was fermented to ethanol, ethanol was distilled, and residual stillage was separated into distillers' grains, centrifuged solids, and stillage solubles. Distillers' grains and centrifuged solids had protein contents (N x 6.25, dry basis) of 42 and 46%, respectively, and accounted for 73 and 8% of total grain nitrogen. Distillers' grains protein was much less soluble than that of unfermented sweet sorghum grain. Seventy-two percent of the nitrogen in stillage solubles passed through a 10,000 molecular weight cut-off membrane. Combined ultrafiltration and high-pressure reverse osmosis effectively processed stillage solubles into a small volume of concentrate with potential feed use and a large volume of permeate, which can be reused for water or safely discarded.