An improved wet milling process is provided that allows for separation of seed coat particles from the horny endosperm particles of seed. The process uses soaking and grinding to produce seed coat flake particles and horny endosperm particles that may be separated using movement of liquid slurry of the particles, providing hydraulic lift to separate the seed coat particles. Improvements in the process allow for omitting addition of sulfur compounds to the process. By-products of wet milling with improved properties are provided.
Description
BRIEF DESCRIPTION OF FIGURES
FIG. 1 shows the ethanol process with separation and recovery of grain components.
FIG. 2 shows the method developed for recovering pericarp (fiber) from corn
Claims
1. A method of separating portions of a plant seed from one another wherein the plant seed comprises a seed coat, germ, and an endosperm comprising a floury endosperm and a horny endosperm, the method comprising:
(i) soaking a plant seed in liquid which does not contain sulfur compounds;(ii) grinding the seed at least once, such that the soaking and grinding produces seed coat particles, germ, horny endosperm particles and floury endosperm particles, wherein the seed coat particles are thinner and flatter in shape than the horny endosperm particles and the production of horny endosperm particles does not increase density of the seed coat flakes;(iii) producing a liquid slurry of the seed coat, horny endosperm and floury endosperm particles;(iv) causing movement of the slurry to produce hydraulic lift such that the seed coat particles rise in the slurry as a result of the hydraulic lift and the horny endosperm particles sink downward or outward in the slurry; and(v) separating the seed coat particles from the horny endosperm particles.
2. The method of claim 1 further comprising soaking and grinding the seed such that the floury endosperm particles are ground more finely than the horny endosperm particles and are dispersed in the slurry.
3. The method of claim 1 further comprising separating germ of the seed from the seed coat and endosperm.
4. The method of claim 1 wherein the seed is soaked in water at temperature of from about 140° F. to about 160° F.
5. The method of claim 1 wherein the seed is soaked in water for about six to about 24 hours.
6. The method of claim 1 further comprising adding an enzyme to the liquid used in soaking the seed.
7. The method of claim 6 wherein the enzyme is alpha amylase.
8. The method of claim 7 wherein the enzyme is added to at least about 0.003% weight dry substance seed.
9. The method of claim 8 wherein the enzyme is added to about 0.006% to about 0.0172% weight dry substance seed.
10. The method of claim 9 wherein the enzyme is added to about 0.013% to about 0.0046% weight dry substance seed.
11. The method of claim 1 wherein the seed coat particles and horny endosperm particles are coarsely ground.
12. The method of claim 1 wherein the seed is soaked until it has a moisture content of about 45%.
13. The method of claim 1 wherein movement of the slurry is produced by a hydrocyclone.
14. The method of claim 13 wherein the separation of seed coat particles and horny endosperm particles occurs at a Baumé of less than about 11.
15. The method of claim 3 further comprising separating the germ from the particles at a first pressure, prior to separating the seed coat particles from horny endosperm particles at a second lower pressure.
16. The method of claim 15 wherein the second pressure is at least about 20 psi.
17. The method of claim 1 wherein the seed is corn seed.
18. A method of separating portions of a plant seed from one another wherein the plant seed portions comprises a seed coat, germ, and an endosperm comprising a floury endosperm and a horny endosperm, the method comprising:
(i) soaking a plant seed in liquid which does not have added sulfur compounds, from about six to 24 hours at a temperature of about 140° F. to 160° F.;(ii) grinding the seed at least once, such that the soaking and grinding produces germ, seed coat particles, germ; and horny endosperm particles and floury endosperm particles, wherein the seed coat particles are thinner and flatter in shape than the horny endosperm particles and the seed coat particles and horny endosperm particles are coarsely ground;(iii) separating the germ from the seed coat and the horny endosperm particles and floury endosperm particles;(iv) producing a liquid slurry of the seed coat, horny endosperm and floury endosperm particles;(v) causing movement of the slurry to produce hydraulic lift, such that the pericarp particles rise in the slurry are a result of the hydraulic lift, and the horny endosperm particles sink downward or outward in the slurry; and(vi) separating the seed coat particles from the horny endosperm particles.
19. The method of claim 18 further comprising adding alpha amylase to the soaking liquid.
20. A method of producing a carbohydrate composition stream for use in ethanol production, the method comprising:
(i) soaking a plant seed in liquid which does not contain sulfur compounds;(ii) grinding the seed at least once, such that the soaking and grinding produces seed coat particles, germ, horny endosperm particles and floury endosperm particles, wherein the seed coat particles are thinner and flatter in shape than the horny endosperm particles and the production of horny endosperm particles does not increase density of the seed coat flakes;(iii) removing the germ particles;(iv) producing a liquid slurry of the seed coat, horny endosperm and floury endosperm particles;(v) causing movement of the slurry to produce hydraulic lift such that the seed coat particles rise in the slurry as a result of the hydraulic lift and are removed from the slurry, and the horny endosperm particles sink downward or outward in the slurry such that the slurry comprises a carbohydrate composition of at least about 40% dry solids; and(vi) using the carbohydrate composition stream in an ethanol producing process.
21. The process of claim 20, further comprising liquefying the carbohydrate composition stream prior to use in the ethanol producing process.
22. The process of claim 21 wherein the stream is liquefied using a high-shear device.
23. A germ by-product of wet milling comprising at least about 42% oil and no non-native sulfur compounds.
24. A seed coat fiber by-product of wet milling comprising less than about 8% dry substance starch and at least about 80% dry substance neutral detergent fiber and no non-native sulfur compounds.
25. A protein by-product of wet milling comprising at least about 45% dry substance protein, no non-native sulfur compounds and available phosphorous of about at least 40%.
26. A yeast cream by-product of wet milling comprising at least about 57% dry substance protein.
27. A syrup by-product of wet milling comprising at least about 0.7% dry substance phosphorus wherein the phosphorus comprises at least about 50% available phosphorus.
28. A carbohydrate composition by-product of wet milling comprising at least about 40% dry solids content.
29. A by-product of wet milling of grain, the by-product selected from the group consisting of:
(i) a germ comprising at least about 42% oil and no non-native sulfur compounds;(ii) a seed coat fiber comprising less than about 8% dry substance starch and at least about 80% dry substance neutral detergent fiber and no non-native sulfur compounds;(iii) a protein compound comprising at least about 45% dry substance protein, no non-native sulfur compounds and at least about 40% available phosphorus;(iv) a yeast cream comprising at least about 57% dry substance protein;(v) a syrup comprising at least about 0.7% dry substance phosphorus wherein the phosphorus comprises at least about 50% available phosphorus; and(vi) a carbohydrate composition comprising at least about 40% dry solids.
30. The by-product of claim 29 wherein the grain is corn.
Patent Application
20070184159
