WET MILLING AND SEPARATION OF WHEAT DISTILLERS GRAINS WITH SOLUBLES INTO DIETARY FIBER AND PROTEIN-FRACTIONS

Wheat-based stillage from a fuel ethanol plant was wet milled by sonication, abrasive stone milling, and blade grinding before fractionation by sieving and centrifugation into distillers' grains (DG), centrifuged solids (CS), and thin stillage. Blade grinding was the most effective method for separating protein and fiber in stillage, with 40% of the fiber being concentrated in DG and over 70% of protein in CS. The DG, which contained over 70% of total dietary fiber, exhibited high water- and oil-absorption capacities and had potential as a fiber ingredient in foods. The CS fraction contained 60% protein and was lower in functionality than DG. Further studies are required to identify potential uses for the fractions and the economic feasibility of the process.