US 7,452,425 B1 · Corn refining process

Abstract

A grain containing starch, such as corn, is refined. The grain is steeped in water at a temperature of about 125 to 160° F., which water is essentially free of sulfurous acid and contains recycled enzymes from downstream processes, in a counter-current steeping reactor for about 10 to 20 hours to produce an aqueous slurry of steeped grain having a moisture content of about 40 to 50 percent. The various components of the grain are then separated and the starch is converted to ethanol.

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Drawings

Claims20

Dependent claims

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.

10 more elements

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 140 to 155° F., is essentially free of sulfurous acid, and contains effective amounts of amylase, protease, and cellulase 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) removing the soft starch from the coarsely ground stream;
(e) 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;
(f) removing the germs from the partially gelatinized stream to produce a degermed stream;
(g) removing the coarse fiber from the degermed stream to produce a hard starch-protein-fine fiber stream;
(h) subjecting the hard starch-protein-fine fiber 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;
(i) exposing the liquefied stream to effective amounts of amylase enzymes to produce a saccharified stream;
(j) removing the fine fiber from the saccharified stream to produce a fiber-free saccharified stream;
(k) removing the protein from the fiber-free saccharified stream to produce a fiber-and-protein-free saccharified stream;
(l) adding an effective amount of yeast to the fiber-and-protein-free saccharified stream and fermenting it to produce carbon dioxide and a fermented stream containing ethanol;
(m) removing the carbon dioxide produced during fermentation and recycling some for gas lift agitation and blanketing;
(n) removing the yeast from the fermented stream to produce a yeast-free fermented stream;
and
(o) distilling the yeast-free fermented stream to produce an ethanol stream and a bottoms stream.

16 more elements

A process for refining grain, the process comprising:

(a) providing grain having a moisture content of about 10 to 30 percent and comprising a pericarp consisting essentially of coarse fiber;
an endosperm consisting essentially of starch, protein, and fine fiber;
and a germ;
(b) steeping the grain in recycled water from downstream processes, which water has a temperature of about 125 to 160° F., is free of sulfurous acid, and contains effective amounts of amylase, protease, and cellulase enzymes, in a counter-current steeping reactor for about 10 to 20 hours to produce an aqueous slurry of steeped grain having a moisture content of about 40 to 50 percent;
(c) coarsely grinding the steeped grain to produce a coarsely ground stream comprising coarse fiber fragments, endosperm 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 fragments and germs and to produce a partially gelatinized stream;
(e) removing the germs from the partially gelatinized stream to produce a degermed stream;
(f) removing the coarse fiber from the degermed stream to produce a starch-protein-fine fiber stream;
(g) subjecting the starch-protein-fine fiber stream to sufficient shear and cavitation forces in a rotary homogenizer to gelatinize substantially all the starch and to produce a liquefied stream;
(h) exposing the liquefied stream to effective amounts of amylase enzymes to produce a saccharified stream;
(i) removing the fine fiber from the saccharified stream to produce a fiber-free saccharified stream;
(j) removing the protein from the fiber-free saccharified stream to produce a fiber-and-protein-free saccharified stream;
(k) adding an effective amount of yeast to the fiber-and-protein-free saccharified stream and fermenting it without the addition of nitrogen compounds to produce carbon dioxide and a fermented stream containing ethanol;
(l) removing the carbon dioxide produced during fermentation and recycling some for gas lift agitation and blanketing;
(m) removing the yeast from the fermented stream in a centrifugal separator to produce a yeast-free fermented stream;
and
(n) distilling the yeast-free fermented stream to produce an ethanol stream and a bottoms stream.

14 more elements

Dependencies are inferred from the claim text.

Description8,018 words

Summary2,604 words

#This invention relates to chemistry. More particularly, this invention relates to food processing. Still more particularly, this invention relates to corn refining.

#1. Corn

#Corn is the most important crop grown in the United States. Corn is sometimes called maize and has the scientific name Zea mays. Corn has a growing season of about four to six months. A mature corn plant consists of a stalk with an ear of corn. The ear of corn consists of about 800 kernels, or seeds, on a cylindrical cob. The kernels are eaten whole and are also processed into a wide variety of food and industrial products.

Brief description of the drawings10 figures

#FIG. 1 is a schematic diagram of a prior art corn refining process for ethanol production based on a conventional dry milling process.

#FIG. 2 is a schematic diagram of a prior art corn refining process for ethanol production based on a conventional wet milling process.

#FIG. 3 is a simplified schematic diagram of the overall corn refining process of this invention.

Detailed description5,267 words

#The process of this invention refines corn. The process separates the various corn fractions and chemically converts the starch to glucose and the glucose to ethanol. The overall process is illustrated in simplified form in FIG. 3. Omitted for clarity are water and steam, two important raw materials for the process. Also omitted for clarity are recycle lines, separations, minor by-product lines, etc. FIG. 4 illustrates the overall process in more detail. The stream containing the starch (and later containing the starch derivatives glucose and ethanol) is considered the primary stream because of its size and economic importance. Various corn components are optionally isolated (removed from the primary stream) at different steps of the process. In general, it is preferred to isolate these components for a variety of reasons, including the fact that the quality and nutritional value of the components deteriorate as the processing continues. These isolated components are suitable for a wide variety of conventional corn refining products, including distillers grains with solubles (DGS), corn grits, starch media, corn oil, coarse fiber (bran), fine fiber, germ oil meal, gluten meal, gluten concentrate (steepwater concentrate), and gluten feed. By-products include carbon dioxide and yeast cream. The individual steps of the process are discussed in detail below.

#A variety of grains with a starch component are advantageously refined with the process of this invention. Suitable grains include corn, rice, oats, sago, barley, canola, cassaya, Jerusalem artichokes, mustard seed, flax, fava beans, lentils, milo, peas, rye, safflower, soybeans, sunflower seeds, tricale, wheat, and the like. The preferred grain is corn because of its large starch component and its abundant commercial availability. The preferred corn is United States grade no. 2 yellow dent corn. For convenience, most descriptions of the process herein refer only to the use of corn as the raw material.

#The first step of the process is to clean the corn, i.e., to separate whole corn kernels from all other matter. Cleaning is preferably performed by passing the corn over or through a series of three varying sized screens. Particles larger than a corn kernel (commonly known as the scalps and consisting of cobs, stalks, dirt, metal, and other extraneous material) are retained on the largest screen and are discarded as waste. Whole corn kernels (and some cob and stalk fragments having the same size as whole corn kernels) are retained on the next largest screen. The whole corn kernels (and other material of the same size) are fed to the steeping reactor described below.

Facts

Application

11/336,324Filed 20 Jan 2006 · continuation in part

Priority

25 Mar 2003

Granted

18 Nov 2008

Term ended

22 Aug 2024

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 516 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification11 codes

A23J 1/12
Obtaining protein compositions for foodstuffs; Bulk opening of eggs and separation of yolks from whites: from cereals, wheat, bran, or molasses
B02B 1/04
Preparing grain for milling or like processes: wet treatment, e.g. washing, wetting, softening
B02B 5/02
Grain treatment not otherwise provided for: combined processes
B02C 9/04
Other milling methods or mills specially adapted for grain: systems or sequences of operations; Plant

Timeline

25 Mar 2003Priority claimedParent application 10/400,020
20 Jan 2006Application filedUS 11/336,324
13 Feb 2006Assigned to Langhauser Associates, Inc.assignment of assignor's interest
18 Nov 2008GrantedUS 7,452,425 B1
22 Aug 2024Term endedEstimated, includes 516 days of adjustment

Corn refining process

Life of this patent

Corn refining process

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims20

Description8,018 words

Drawings

Classification11 codes

Life of this patent

Description8,018 words