Corn wet milling process

• US 20070020375A1
• Filed: 07/20/2005
• Published: 01/25/2007
• Est. Priority Date: 07/20/2005
• Status: Abandoned Application

• Current Assignee: Tate & Lyle Ingredients Americas, Inc. (TATE & LYLE PLC)
• Original Assignee: Tate & Lyle Ingredients Americas, Inc. (TATE & LYLE PLC)
• Inventors: Jansen, Robert, Lutz, Eric, Walker, Gordon, Sass, David
• Application Number:
  US11/185,527
• Publication Number:
  US 20070020375A1
• Time in Patent Office: Days
• US Class Current: 426/622
• CPC Class Codes: A23J 1/12 from cereals, wheat, bran, or molasses
• CPC Class Codes: A23K 10/37 from waste material from hydrolysates of wood or straw A23K10/32; from molasses A23K10/33
• CPC Class Codes: A23K 20/163 Sugars; Polysaccharides
• CPC Class Codes: A23L 29/35 Degradation products of starch, e.g. hydrolysates, dextrins; Enzymatically modified starches
• CPC Class Codes: A23L 33/22 Comminuted fibrous parts of plants, e.g. bagasse or pulp
• CPC Class Codes: A23L 7/104 Fermentation of farinaceous cereal or cereal material; Addition of enzymes or microorganisms
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02P 60/87 Re-use of by-products of food processing for fodder production

Abstract

A corn wet-milling process comprises steeping corn kernels in an aqueous liquid, which produces softened corn; milling the softened corn in a first mill, which produces a first milled corn; separating germ from the first milled corn, thereby producing a germ-depleted first milled corn; milling the germ-depleted first milled corn in a second mill, producing a second milled corn; separating the second milled corn into a first starch/protein portion that comprises starch and protein and a first fiber portion that comprises fiber, starch, and protein; milling the first fiber portion in a third mill, which produces a milled fiber material that comprises fiber, starch, and protein; separating at least some of the starch and protein in the milled fiber material from the fiber therein, producing a second fiber portion that comprises fiber and starch and a second starch/protein portion that comprises starch and protein; and contacting the second fiber portion with at least one enzyme to convert at least some of the starch therein to dextrose. The converted material is screened using one or more screens to separate the fiber from the liquor. The liquor can be fermented to ethanol, or refined to dextrose. The fiber can be pressed and dried as an animal feed.

Claims

1. A process comprising:

steeping corn kernels in an aqueous liquid, producing softened corn;

milling the softened corn in a first mill, producing a first milled corn;

separating germ from the first milled corn, producing a germ-depleted first milled corn;

milling the germ-depleted first milled corn in a second mill, producing a second milled corn;

separating the second milled corn into a first starch/protein portion that comprises starch and protein and a first fiber portion that comprises fiber, starch, and protein;

milling the first fiber portion in a third mill, producing a milled fiber material that comprises fiber, starch, and protein;

separating at least some of the starch and protein from the fiber in the milled fiber material, producing a second fiber portion that comprises fiber and starch and a second starch/protein portion that comprises starch and protein; and

contacting the second fiber portion with at least one enzyme to convert at least some of the starch therein to dextrose.

2. The process of claim 1, further comprising converting at least some of the dextrose to ethanol by fermentation.

3. The process of claim 1, wherein at least some of the starch in the second fiber portion is gelatinized by heating, is at least partially liquefied by alpha amylase, and is at least partially saccharified by amyloglucosidase, producing a material comprising dextrose and fiber.

4. The process of claim 3, further comprising separating fiber from dextrose by washing the material that comprises dextrose and fiber with at least one screen, producing a dextrose-depleted fiber material and a dextrose-rich material.

5. The process of claim 1, further comprising separating the first starch/protein portion into a starch-rich material and a protein-rich material.

6. The process of claim 5, further comprising enzymatically converting at least some of the starch-rich material into dextrose.

7. The process of claim 1, wherein the separation of the milled fiber material into a second starch/protein portion and a second fiber portion comprises washing with screens.

8. The process of claim 7, wherein the number of screens used to separate the milled fiber material into a second starch/protein portion and a second fiber portion is determined primarily by the desired recovery of protein and secondarily by the desired recovery of starch.

9. The process of claim 8, wherein the second fiber portion comprises about 15-60 wt % starch on a dry solids basis.

10. The process of claim 1, further comprising adding a starch-containing stream to the second fiber portion prior to contacting the second fiber portion with at least one enzyme to convert at least some of the starch therein to dextrose.

11. A process comprising:

steeping corn kernels in an aqueous liquid, producing softened corn;

milling the softened corn in a first mill, producing a first milled corn;

separating germ from the first milled corn, producing a germ-depleted first milled corn;

milling the germ-depleted first milled corn in a second mill, producing a second milled corn;

separating the second milled corn into a first starch/protein portion that comprises starch and protein and a first fiber portion that comprises fiber, starch, and protein;

milling the first fiber portion in a third mill, producing a milled fiber material that comprises fiber, starch, and protein; and

contacting the milled fiber material with at least one enzyme to convert at least some of the starch therein to dextrose.

12. The process of claim 11, further comprising converting at least some of the dextrose to ethanol by fermentation.

13. The process of claim 11, wherein at least some of the starch in the milled fiber material is gelatinized by heating, is at least partially liquefied by alpha amylase, and is at least partially saccharified by amyloglucosidase, producing a material comprising dextrose and fiber.

14. The process of claim 13, further comprising separating fiber from dextrose by washing the material that comprises dextrose and fiber with at least one screen, producing a dextrose-depleted fiber material and a dextrose-rich material.

15. The process of claim 11, further comprising separating the first starch/protein portion into a starch-rich material and a protein-rich material.

16. The process of claim 15, further comprising enzymatically converting at least some of the starch-rich material into dextrose.

17. The process of claim 11, further comprising adding a starch-containing stream to the milled fiber material prior to contacting the milled fiber material with at least one enzyme to convert at least some of the starch therein to dextrose