Patent ID: 7452425
Filing Date: 2008-11-18
Classification: A23J,B02B,B02C,C12P,Y02E

Abstract:
1. A process for refining corn, the process comprising: (a) providing corn kernels having a moisture content of about 10 to 30 percent and comprising: (i) a pericarp comprising coarse fiber; (ii) an endosperm comprising soft starch, hard starch, protein, and fine fiber; and (iii) a germ; (b) steeping the corn kernels in recycled water from downstream processes, which water has a temperature of about 125 to 160° F., is essentially free of sulfurous acid and contains effective amounts of amylase enzymes, in a counter-current steeping reactor for about 10 to 20 hours to produce an aqueous slurry of steeped corn kernels having a moisture content of about 40 to 50 percent; (c) coarsely grinding the steeped corn kernels to produce a coarsely ground stream comprising coarse fiber, soft starch, hard starch-protein-fine fiber fragments, and germs; (d) heating the coarsely ground stream in the presence of effective amounts of amylase enzymes to gelatinize starch clinging to the coarse fiber and germs and to produce a partially gelatinized stream; (e) subjecting the partially gelatinized stream to sufficient shear and cavitation forces in the presence of effective amounts of amylase enzymes to gelatinize substantially all the starch and to produce a liquefied stream; (f) exposing the liquefied stream to effective amounts of amylase enzymes to produce a saccharified stream; (g) adding an effective amount of yeast to the saccharified stream and fermenting it to produce carbon dioxide and a fermented stream containing ethanol; (h) removing the carbon dioxide produced during fermentation and recycling some for gas lift agitation and blanketing; and (i) distilling the fermented stream to produce an ethanol stream and a bottoms stream.