Whole grain, such as wheat, barley, rye, and/or rice, can be processed by (a) steeping the grain or at least partially dehulled grain in an aqueous liquid to produce softened grain, (b) milling the softened grain to produce milled grain, (c) liquefying the milled grain by contacting it with amylase and heating it to a temperature of at least about 50° C., producing a liquefied material, (d) at least partially saccharifying the liquefied material by contacting it with amyloglucosidase at a temperature of at least about 50° C., producing a first saccharified material, and (e) separating fiber and germ from the first saccharified material, producing a screened material that is substantially free of fiber and wheat germ. The process also includes the steps of (f) further saccharifying the screened material by contacting it with amyloglucosidase at a temperature of at least about 50° C., producing a second saccharified material, (g) membrane filtering the second saccharified material, producing a permeate that comprises primarily dextrose and other soluble components and a retentate that comprises insoluble protein, and (h) purifying the permeate by chromatographic separation, producing a purified dextrose stream. The chromatographic separation can also produce a raffinate, and the process can further include the steps of (i) combining the retentate from the membrane filtration and the raffinate from the chromatographic separation to form a fermentation medium, (j) fermenting the fermentation medium aerobically with a microorganism, (k) separating a protein product that comprises insoluble protein and microorganism from the medium, and (l) drying the protein product.