As mentioned earlier in the discussion of dry-grind technology, the dry-grind process is being adapted to capture some of the advantages of the wet-milling system. The Quick Germ [34] and Quick Fiber [35] fractionation methods increase processing efficiency as well as the value of feed coproducts. These methods add technology to the beginning of the dry-grind process, removing the germ and fiber fractions of the corn kernel prior to starch processing. First, the corn is soaked in water for 3-12 hours to hydrate the germ, which is recovered by density separation. Next, the specific gravity of the mash is adjusted and pericarp fiber is recovered using hydrocyclones. The starch is then fermented in the traditional dry-grind process, and the germ and fiber can be processed sepa­rately into other value-added products: corn oil (from germ) and corn fiber oil and corn fiber gum (from corn fiber). Corn fiber oil, which is distinct from traditional corn germ oil, is potentially a valuable coproduct because it contains phytosterols known to have cholesterol-lowering properties. Another process, known as enzymatic milling or the E-mill process, refers to the addition of proteases and amylases prior to germ separation [36]. E-milling allows recovery of the gluten, while avoiding a full steeping process and the health and environ­mental concerns associated with sulfite.

Because the germ and fiber do not enter the fermenter, the fermentation residuals have lower fiber content and correspondingly higher protein content, resulting in a higher-value feed product. On the process side, these modified milling technologies increase the effective capacity of fermentation tanks, because removal of the germ and fiber frees reactor volume for additional starch. Bringing these modified processes to the dry-grind plant would therefore increase the facility’s ethanol production by 8 to 27% [37].