BACKGROUND OF INVENTION Corn fiber oil, not to be confused with corn oil derived from corn meal, is known to contain nutritional constituents such as sterols, sterol esters. stanols, and stanol esters, as well as, triacylglycerols and other oils, which are non- triacylglycerols. Importantly, the corn fiber oil contains an amount of phytosterol derivatives or plant sterols, which equal approximately 17% by weight of the total corn fiber oil, with the triacylglycerols and other non-triacylglycerols comprising the remaining constituents found in the corn fiber oil. The phystosterol derivatives are comprised of the sterols, stanols, and esters of the sterols and stanols already listed.

More specifically, the corn fiber oil contains approximately 2% by weight of free sterols, 6% by weight of sterol ferulate esters, and 9% by weight of sterol fatty esters, also known as stanol esters based on the weight of the corn fiber oil. The concentration of phytosterols in the corn fiber oil is higher than in other known oils.

For example, rice bran oil contains an amount of sterol esters equal to about 1.5% by weight of the rice bran oil and wheat oil contains an amount of phytosterols equal to about 3.0% by weight of the wheat oil.

The phytosterol constituents are important because they can be used to reduce cholesterol levels in humans. It is known that ingestion by humans of phytosterols can help to lower cholesterol levels in the subject consuming the phytosterol, with the stanols, in particular, resulting in lower cholesterol levels in the

subject. As such, the phytosterol constituents are used in, or are substances similar to, substrates used as cholesterol-reducing ingredients found in both pharmaceutical and food based cholesterol-lowering products. Many of these compositions have proven to be effective in lowering cholesterol. Thus, inclusion of corn fiber oil in a person's diet can be beneficial to lowering cholesterol.

The corn fiber oil containing the phytosterols is found in corn bran and corn fiber. Corn bran is derived from dry milling kernels of corn that have not been steeped, so that the outer layers of the kernels are separated into what is known as the corn bran. The corn fiber is obtained through a wet milling process, which involves steeping the corn kernels followed by grinding and separating the outer layer of kernels from the remainder of the corn kernels. Both the corn bran and corn fiber are derived from the outer layers of the corn kernel. The corn bran and corn fiber both contain corn fiber oil and, as such, the corn bran and the corn fiber will be referred to throughout as corn bran. The corn bran is separated from the remainder of the corn kernel, including the corn meal, corn starch, and corn oil. The corn bran contains an amount of corn fiber oil equal to between about 3.0% and about 4.8% by weight of the total corn bran. Unfortunately, while the corn fiber oil is desirable for human health and has a variety of different uses, it suffers from being particularly difficult to extract from the corn bran. As such, it has not been known to commercially extract corn fiber oil from corn bran. The methods that are known are generally done on a lab scale and not on a scale designed to commercially harvest and produce corn fiber oil. The known methods involve grinding corn bran to a smaller particle size.

The corn fiber oil is difficult to extract because it has a low density and is tightly bound to the fiber comprising the corn bran. Past methods for extracting the corn fiber oil from the corn bran have included grinding the corn bran to an average of about a #20 U. S. mesh particle size, with the grinding done for example, in a pin mill. Once ground, the corn bran is then contacted with a solvent and some of the corn fiber oil is removed from the ground corn bran. Generally, no more than 1.0% by weight of the corn fiber oil is extracted, meaning that if it is assumed that there is generally 4.8% by weight of corn fiber oil in the corn bran, less than 25% by weight

of the available corn fiber oil is extracted. To extract the corn fiber oil, typically, the ground corn bran is passed through a hexane extraction unit. Because of the fine particle size of the ground corn bran it tends to clog the extraction unit and consequently the hexane does not readily percolate through the corn bran to remove the corn fiber oil. Also, the small particle size of the corn bran causes the extracted corn fiber oil to be clouded with debris from the ground corn bran. As can be seen, the prior methods for producing the corn bran suffer from a number of disadvantages. In particular, it has been found that the corn bran produced does not allow for extraction of a high percentage of the corn fiber oil, it readily clogs the extractor unit, and it results in a corn fiber oil contaminated with debris. Thus, it is desirable to have a method that results in a corn bran that can have greater amounts of corn fiber oil extracted from the corn bran. It is also desired to have a method that results in a corn bran that can have the corn fiber oil extracted and that does not cause the corn fiber oil to be clouded with debris.

SUMMARY The present invention relates to a method for preparing corn bran for extraction of corn fiber oil from the corn bran. The method involves grinding an amount of corn bran so that the ground corn bran preferably has a consistency ranging between a coarse bran having a particle size equal to about a #5 U. S. mesh average particle size and a flour. More preferably, the corn bran is ground so that it has a particle size equal to or less than a #20 U. S. mesh average particle size.

Following grinding, the method involves restructuring the corn bran by passing the ground corn bran through an expander device. Typically, the expander device is an extruder device that will compress the corn bran and alter its structure so that the corn fiber oil contained in the corn bran can be more easily extracted. Expansion essentially involves taking ground corn particles and reforming them into a solid expanded material that allows solvent to readily percolate through the restructured corn bran. Grinding and expanding the corn bran will result in a restructured corn bran that allows for a greater extraction of the corn fiber oil than non-treated corn bran and a restructured corn bran that has improved handling characteristics. The

restructured corn bran generally does not contaminate the solvent with debris from the corn bran. Also, the reconstructed corn bran tends not to clog a solvent extractor. As such, the expanded and restructured corn bran will allow for at least about 1 % by weight of corn fiber oil to be extracted without contaminating the corn fiber oil with debris from the corn bran.

In addition to grinding and expanding the corn bran, it is preferred, but no required, to dry the corn bran after expanding. It is also preferred, but not required, to dry the corn bran prior to grinding.

DETAILED DESCRIPTION The present invention relates to a method for preparing corn bran for extraction of corn fiber oil from the corn bran, wherein the corn fiber oil can be readily used for human consumption to reduce cholesterol. The corn bran, as discussed in the background of the invention, includes both corn bran and corn fiber.

The present method is especially advantageous because it preferably allows for the extraction of greater than 1% by weight of the corn fiber oil in the corn bran. The method involves forming an expanded restructured corn bran, with the method for making the expanded restructured corn bran involving grinding an amount of corn bran and then expanding the ground corn bran. Expanding is a process whereby the ground corn bran is passed into an extruder or similar device, so that as the corn bran passes through the extruder it is squeezed and expanded. Other steps can be included in the present method, but it is most important to grind and expand the corn bran. Passing the ground corn bran into an expander is important because this allows for restructuring of the corn bran particles so that they are held together and have a different structure so as to allow for easier extraction of the corn fiber oil with a solvent. The expanded corn bran that is formed is an expanded restructured homogenous mass that has an open pore structure and is known as a collet. The solvent appears to readily percolate through the restructured corn bran and extract the corn fiber oil. Also, the expanded corn bran will not cloud the finished corn fiber oil product and is easier to handle than untreated corn bran.

The method is initiated by obtaining an amount of corn bran, which is also known as corn fiber, and, as mentioned, is derived from a corn kernel's hull.

Specifically, the corn bran consists of the outer layers of the corn seed or kernel that are separated from the remainder of the seed during, for example, a wet milling process. The corn bran contains limited amounts of starch and protein, and an amount of corn fiber oil, which is generally believed to be present in an amount equal to from about 2% to about 4.8% by weight of the corn bran. More typically, the corn bran is believed to contain an amount of corn fiber oil equal to about 4.8% by weight of the corn bran. The corn bran will preferably be of a size that can pass through a #5 U. S. standard testing sieve, so that the corn bran has a #5 U. S. standard testing average particle size. But, since the corn bran will be ground anyway, the particle size of the corn bran is not that important. The corn bran, however, should be of a size that when passed through the grinding step, the desired size for the corn bran prior to restructuring can be achieved. Preferably, the corn bran will contain an amount of water equal to no more than about 25% by weight of the corn bran, however, depending on how the corn bran is processed prior to restructuring, it may contain a lesser amount of water. The corn bran prior to restructuring typically has a density of about 10 lbs./ft3, meaning that the corn bran has a relatively low density and that the oil will be tightly bound to the corn bran. Finally, it is preferred if the corn bran is not burnt or toasted, which can happen if the corn bran is dried prior to restructuring at too high of a temperature for too long.

Once an amount of the corn bran is obtained it can be conditioned or cooked. The conditioning step is not required, but it can be included as part of the method. If the corn bran is conditioned, it is preferably done so that the corn bran is exposed to a temperature of greater than 90° F. In essence, conditioning is simply a process whereby the corn bran is cooked for a period of time, with that in mind, any of a variety of devices can be used to cook the corn bran.

The corn bran is preferably dried prior to grinding, regardless of whether it has been conditioned or cooked, but drying prior to grinding is not required. The corn bran should be sufficiently dried so that it has a moisture content equal to or less than about 15% by weight of the corn bran. More preferably, the corn bran

should have a moisture content equal to between about 2% and about 8% by weight of the corn bran. The lower moisture content in the corn bran allows for better corn fiber oil extraction from the corn bran. Also, the lower moisture content allows for better grinding of the corn bran. If the corn bran is dried, it should not be exposed to temperatures that will burn or toast the corn bran. As such, the corn bran can be dried in a variety of ways; however, it is preferred to dry the corn bran using low temperature drying of about 180° F for a time period of about two (2) hours. Keep in mind that the corn bran burns at a temperature of roughly 700° F, meaning any temperature below this may be used.

Once the corn bran has been conditioned, dried, or simply taken directly from the corn kernel, the corn bran is ground to a smaller particle size. The corn bran can be ground in any of a variety of devices that will reduce the particle size of the corn bran. The object of grinding the corn bran is to reduce the size of the corn bran, so that the corn bran has an average U. S. standard testing sieve particle size of #20 or less and more preferably a flour grade particle size or an average U. S. standard testing sieve particle size of #60 or less. It is further known that the finer the corn bran is ground, the better the corn fiber oil extraction will be.

As mentioned, any of a variety of devices can be used to grind the corn bran to an average U. S. standard testing sieve particle size of #20 or less. Included among the suitable devices are a flaking roll, a pin mill grinder, a hammer mill, and any of a variety of other devices, which can reduce the particle size of the corn bran. The grinding can be done at a variety of temperatures, pressures, and other variables, so long as the corn bran is not burnt or damaged and the particle size is reduced to the desirable size.

Upon completion of grinding, the corn bran is then passed into a device for expanding and restructuring the corn bran. Typically, this is done in an extruder device, whereby the corn bran is passed through the extruder so that the corn bran is compressed and exposed to heat, moisture, and pressure. The extruder will restructure the corn bran so that the restructured corn bran will no longer have a flour consistency and will essentially have a larger particle size than the ground corn bran. The restructured corn bran is also known as a collet. Generally, an extruder is

a tubular structure having a screw type member contained therein and means for heating, moisturizing, and pressurizing the contents within the extruder. The screw member will turn within the tubular member to compress and compact the corn bran.

As the corn bran passes through the extruder it goes through a die, after passage through the die the change in pressure will cause some of the moisture in the corn bran to vaporize and the corn bran will expand. The die on the extruder can be of a variety of sizes, but will generally have an opening or openings ranging between about 3/8 inches and about 1/2 inches. An expander may have more than one die.

An example of a suitable extruder device for use in the present invention is an extruder made by Anderson International Corp. The restructured corn bran is advantageous because it does not readily clog an extractor unit and the corn fiber oil can be readily extracted from the corn bran. When the restructured corn bran comes out of the extruder or expander it will have an open pore structure, the corn bran particles will be formed into an homogenous mass, and the steam will flash off the corn bran. Thus, the extruder or expander can have a variety of parameters so long as an expanded corn bran is formed that fits the previous description. Also, the corn fiber oil extracted from the restructured corn bran tends not to be clouded with solid corn bran material.

After restructuring, it is preferred, but not required, to dry the restructured corn bran. The restructured corn bran should be sufficiently dried so that it has a moisture content equal to or less than about 15% by weight of the corn bran. More preferably, the corn bran should have a moisture content equal to between about 2% and about 8% by weight of the corn bran. The lower moisture content in the corn bran allows for better corn fiber oil extraction from the corn bran. It has been observed that the corn fiber oil is more readily removed from dry restructured corn bran than wet restructured corn bran. If the restructured corn bran is dried, it should not be exposed to temperatures that will burn or toast the restructured corn bran. As such, the restructured corn bran can be dried in a variety of ways; however, it is preferred to dry the restructured corn bran using low temperature drying of about 180° F for a time period of about two (2) hours. Keep in mind that the corn bran

burns at a temperature of roughly 700° F, meaning any temperature below this may be used.

After the corn bran has been restructured, it is then exposed to a solvent extraction system that removes an amount of the corn fiber oil from the restructured corn bran. Any of a variety of extraction methods can be used, however, it is preferred to use a hexane extraction method, as this is commercially acceptable and has proven effective in removing the corn fiber oil from corn bran. The restructured corn bran will be exposed to a sufficient amount of hexane for a sufficient period of time to extract a portion of the corn fiber oil held by the corn bran. The method for extracting the corn fiber oil from the corn bran generally involves exposing the restructured corn bran to an amount of hexane for a period of time equal to between about 20 minutes and about 90 minutes. The amount of hexane added will be an amount sufficient to equal at least a 1: 1 by weight ratio with the restructured corn bran; however, other amounts of hexane may be used. Other solvents besides hexane can be used, but hexane is most preferred. Among the solvents that can be used to extract the corn fiber oil are supercritical CO2, butane, isopropanol, isooctane, propane, hexane, acetone, isohexane, heptane, methylpentanes, ethanol, methanol, and other solvents.

The hexane will separate the corn fiber oil from the corn bran to form a miscella, which is comprised of corn fiber oil and hexane. The hexane and corn fiber oil in the miscella must then be separated from one another so that the corn fiber oil can be isolated and used. Generally, this is done by heating the miscella to a temperature ranging between about 140° F and about 220° F. The miscella can be heated in a vacuum of between about 12 inches of mercury and about 15 inches of mercury, wherein the combination of the vacuum and heat will cause the hexane to vaporize away from the corn fiber oil. Any temperature can be used as long as the molecular structure of the corn fiber oil is not damaged.

The present method can be part of a continuous process or a batch process.

The following examples are for illustrative purposes only and are not meant to limit the claims in any way. Example 2 is for comparative purposes only.

EXAMPLES Example 1 A test was conducted to determine how much corn fiber oil could be extracted from corn bran by passing ground corn bran through an extruder. An amount of corn bran, also known as corn fiber, was obtained having an amount of moisture equal to about 11.64% by weight of the total corn bran and a density equal to about 10.8 lbs./ft3.

Once the corn bran was obtained, approximately 450 pounds (Ibs.) of the corn bran was placed in a French Stack Cooker, model number 15016, manufactured by the French Oil Mill company. The cooker had a diameter of approximately 30 inches and contained four (4) horizontal trays. The corn bran was placed on the top tray in the cooker, with the corn bran being moved downward so that the corn bran contacted each of the four (4) trays, thereby exposing the corn bran to different temperatures on each of the trays. The corn bran material was evenly dispersed on the four (4) trays, with the corn fiber material exposed to trays heated with 100 psi of steam in the French cooker. Tray 1, or the tray in the top of the French cooker, had a temperature of about 237° F; tray 2, which was second from the top, had a temperature of about 193° F; tray 3, third from the top, had a temperature of 146° F; and the bottom tray, tray 4, had a temperature of 200° F. The corn bran was left in the French Cooker for a period of time equal to 20 minutes.

A flaking roll machine known as a Bauer Flaking Roll was used to flake the conditioned corn bran to form a flaked corn bran. The Bauer Flaking Roll was comprised of a pair of rollers each having a diameter of 14 inches and a width of 24 inches, with a gap setting between the two rollers equal to about. 015 inches.

One of the rollers rotated at a speed equal to about 377 revolutions per minute (rpm) and the other roller rotated at a speed equal to about 424 rpms. There was a 11 % speed differential between the rolls. Passage through the flaking roll formed the corn bran into a flaked corn bran having a reduced particle size.

The flaked corn bran was next placed in an extruder manufactured by Anderson International Corp. Specifically, the flaked corn bran was passed into an Anderson 4.5 inch Expander Cooker having a solvex shaft configuration and a die

size of 3/8 inches. Water was injected into the extruder to moisten the corn bran and to help cause restructuring of the corn bran. The water was added at a rate of 90 lbs./hour. The shaft rotated at a speed of 190 rpm and the expanded corn bran, also known as corn bran collets, came out at a temperature of about 239° F. The corn bran collets will be referred to throughout the examples as expanded or restructured corn bran. The temperature of 239° F was achieved by injecting an amount of steam into the expander.

The restructured corn bran was then placed in a Crown Model 2 continuous extractor, which slowly pulled the corn bran through a hexane solvent bath. The extractor had a capacity of 7.01 ft3 so that an amount of corn bran equal to 142 Ibs./hour could pass through the extractor. Approximately, 272 Ibs. of restructured corn bran was passed through the extractor so that the corn bran was exposed to the hexane for about 45 minutes. The restructured corn bran was exposed to an amount of hexane so as to separate the corn fiber oil from the corn bran. As the restructured corn bran passed through the extractor, an amount of hexane solvent was mixed with the corn bran. Enough hexane was added so that there was a solvent flow of 204 lbs./hour. The solvent was added in an amount sufficient to equal 1.4 parts by weight of solvent to 1 part by weight of corn bran.

The temperature in the Crown 2 extractor was an average of 124° F. After the hexane extraction of the corn bran was complete, approximately 244 lbs. of the corn bran remained, with the loss in weight primarily attributed to oil removal and moisture loss, and some of the corn bran remaining in the extractor.

The hexane, after contacting the restructured corn bran, contained an amount of corn fiber oil. The corn fiber oil was then separated from the hexane by vaporizing the hexane at a temperature of approximately 220° F and a vacuum at approximately 12 inches of mercury. The hexane was vaporized in a Luwa thin film evaporator, fabrication number L-324. It was found that the hexane had removed approximately 1.4 lbs. of corn fiber oil, as that was the amount of corn fiber oil remaining in the batch tank after the hexane had been vaporized. This means that approximately 0.51 % by weight of the corn fiber oil had been recovered from the corn bran.

Example 2 A test similar to Example 1 was conducted except the corn bran material was not flaked or extruded. The corn bran was conditioned the same as Example 1. After conditioning, the corn bran was ground in a hammer mill. As such, 259 lbs. of milled corn bran was exposed to the hexane extraction step disclosed in Example 1. The hexane was then separated from the corn fiber oil under the same conditions disclosed in Example 1, so that 1.1 lbs. of corn fiber oil remained. This means that approximately 0.42% by weight of the oil had been recovered from the corn bran.

Example 3 An amount of corn bran, approximately 200 lbs., was passed twice through a contraplex pin mill. The contraplex had rotating elements on the door and in the mill of the device, with the elements rotating in opposite directions. The contraplex was operated with just the mill side pins rotating at 9048 rpm, with the contraplex made by Alpine and having model #250CWS. The ground corn bran had a particle size equivalent to flour after grinding. Following grinding the corn bran was then restructured and expanded by passing the corn bran into an expander, made by Anderson International Corp. The expander had a four (4) inch screw and two (2) die openings of 3/8 inches and formed approximately 200 lbs. of expanded corn bran.

An amount of the expanded corn bran, 16.7 lbs., was dried for two (2) hours at 180° F, to lower the moisture level in the expanded or restructured corn bran to about 8% by weight. Upon completion of expansion and drying, the dried restructured corn bran was subjected to three (3) hexane washes, with the hexane covering the corn bran. The amount of hexane used to wash the corn bran was equal to about 56.5 Ibs. The first hexane wash soaked the corn bran in hexane for five (5) hours. The second hexane wash soaked the corn bran in hexane for fifteen (15) hours and the third hexane wash soaked the corn bran in hexane for five (5) hours.

The hexane extracted an amount of corn fiber oil and formed a miscella, which is a

composition comprised of corn fiber oil and hexane. The miscella from the three washes were combined. The corn fiber oil was then recovered from the hexane by vaporizing the hexane at a temperature of 160° F and a vacuum of 10 inches of mercury. The hexane was vaporized in a pilot plant rising film glass evaporator glass plant, made by Corning Glass Works, Corning, New York, and having serial #9015. After separation in the pilot plant evaporator, the miscella was placed in a rotavapor device having a temperature of 160° F and a vacuum of 25 inches of mercury. The rotavapor was used to separate the remaining hexane from the corn fiber oil. The rotavapor was model #R114, made by Buchi, and distributed by Beckman Instruments Inc., located in Westbury, New York. It was found that an amount of corn fiber oil equal to approximately 0.426% by weight of corn bran had been recovered. The remaining corn fiber oil was determined by weighing it on a standard scale.

Example 4 The exact same test performed in Example 3 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.10% by weight of the corn bran was recovered.

Example 5 The exact same test performed in Example 3 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.83% by weight of the corn bran was recovered.

Example 6 The exact same test performed in Example 3 was performed in the present example, except that prior to grinding in the pin mill the amount of corn bran, 16.7 lbs., was dried for two (2) hours at 180° F, to lower the moisture level in the corn bran to about 2% by weight of the corn bran. After expansion the corn bran was then dried again for two (2) hours at 180° F, to further lower the moisture level in the corn fiber to about 2% by weight of the corn bran. The dried restructured corn

bran was subjected to the same hexane washing step of Example 3. It was found that an amount of corn fiber oil equal to approximately 2.08% by weight of corn bran had been recovered.

Example 7 The exact same test performed in Example 6 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.80% by weight of the corn bran was recovered.

Example 8 The exact same test performed in Example 6 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 2.05% by weight of the corn bran was recovered.

Example 9 The exact same test performed in Example 6 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 2.20% by weight of the corn bran was recovered.

Example 10 The exact same test performed in Example 6 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 2.20% by weight of the corn bran was recovered.

Example 11 The exact same test performed in Example 6 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 2.21% by weight of the corn bran was recovered.

Example 12 The exact same test performed in Example 3 was performed in the present example, except that instead of grinding, the corn bran was flaked in a flaking roll device at 800 psi. The psi relates to the pressure between the flaking rolls, which comprise the flaking roll device. The flaking roll device was made by Ferrell-Ross a division of Bluffton Agri/Industrial Corp., located in Bluffton, Indiana. The flaking roll device had split rolls with the rolls being 24 inches by 24 inches. A 11 % differential was used to flake the corn bran. The gap setting was not determined on the rolls, but the rolls were brought together and then barely separated. The flaked corn bran was then expanded, dried, and extracted the same as in Example 3. It was found that an amount of corn fiber oil equal to approximately 1.27% by weight of corn bran had been recovered.

Example 13 The exact same test performed in Example 12 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.23% by weight of the corn bran was recovered.

Example 14 The exact same test performed in Example 12 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.07% by weight of the corn bran was recovered.

Example 15 The exact same test performed in Example 12 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 0.90% by weight of the corn bran was recovered.

Example 16 The exact same test performed in Example 12 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.16% by weight of the corn bran was recovered.

Example 17 The exact same test performed in Example 12 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.23% by weight of the corn bran was recovered.

Example 18 The exact same test performed in Example 12 was performed in the present example. It was found that an amount of corn fiber oil equal to approximately 1.15% by weight of the corn bran was recovered.

As can be seen from the above examples, when the corn bran was restructured, extraction yields of corn fiber oil improved. Especially good yields of corn fiber oil were recovered when the corn bran was dried, double ground, restructured in an expander, and then dried, as disclosed in Examples 6,7,8,9,10, and 11.

Thus, there has been shown and described a novel method related to preparing corn bran for corn fiber oil removal which fulfills all the objects and advantages sought therefore. It is apparent to those skilled in the art, however, that many changes, variations, modifications, and other uses and applications for the subject method are possible, and also such changes, variations, modifications, and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.