WO1992007474A1

WO1992007474A1 - High fiber and low ash cereal fibers

Info

Publication number: WO1992007474A1
Application number: PCT/US1991/007942
Authority: WO
Inventors: Yu-Chia Terry Chou
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 1990-11-06
Filing date: 1991-11-05
Publication date: 1992-05-14
Also published as: AU9016291A

Abstract

A novel and simple method for efficiently removing the protein, ash and carbohydrate components, and phytic acid from cereal grain brans, to produce a non-white fiber concentrate with an increased total dietary fiber content and optionally a decreased ash content and phytic acid by treatment with acid and/or base. The resulting dietary fiber product is suitable for human consumption or further bleaching and may be used in food products to raise fiber content and in pharmaceutical products.

Description

TITLE HIGH FIBER AND LOW ASH CEREAL FIBERS

BACKGROUND OF THE INVENTION

The present invention relates to a dietary fiber product. In particular it relates to a process of preparing, from cereal grain brans, a high fiber dietary product which may be used in cereals, crackers, cake mixes, breads, baked goods, dietary drinks and pharmaceutical products.

The current market needs a high fiber dietary product derived from cereal-based substances for consumer appeal and to meet the increased demand for food products high in dietary fiber and low in caloric content.

Agricultural by-products, cereal grain brans and the like have been suggested as sources of dietary fiber, energy, carbohydrate and protein. Carbohydrate and protein are removed from plant material by extraction processes which presumably leaves fibrous material as a residue or by-product. This resulting fibrous material is used as or in animal feeds, is used in paper processes or is discarded.- For example, Saunders et al., U.S. Patent

No. 3,859,451, disclose a process for extracting protein from illfeed (the fragments of wheat kernel, bran and shorts left after milling of wheat to produce flour and germ) . In a preferred embodiment of the invention the millfeed is first mixed with aqueous alkali and the mixture is subjected to blending action. Following treatment with alkali and an optional treatment with 0.1_. to 1.0% bisulfite, the mixture is filtered to separate the juice containing the protein product from the solid fibrous residue. After separation, the fibrous residue has the following composition: 14% protein, 1.3% fat, 13.2% fiber, 12.6% starch, 4% ash and 11% water. It is suggested that when the millfeed is treated with ammonia in the extraction process, that the fibrous residue is beneficial to ruminant animals.

Schmidt, U.S. Patent No. 4,711,789, utilizes pea flour, ground pea hulls, ground pea cotyledons, ground triticale hulls and isolated pea protein in combination with wheat flour to make high fiber breads or extruded edible products. The quality of the products is controlled by the composition of the fiber fractions (pea or triticale) , the flours (pea or wheat) and pea protein. The fiber fractions are prepared for use by grinding the fiber to a specified particle size.

A method for the preparation of flour from soybean seed coats for incorporation into bread is disclosed in Glade et al., U.S. Patent No. 3,573,061. The seed coats are acid treated for from 5 minutes to 48 hours at from 70° to 212°F (26° to 100°C) and at acid concentrations of 1 to 5 normal. The seed coat flour is substituted for 25 to 45% of the wheat flour to manufacture a low-calorie bread. In order to obtain an acceptable bread, it is preferred that egg yolk and hydroxylated lecithin be added to the dough formulation.

Conrad, U.S. Patent No. 4,377,602, discloses a procedure by which all proteins and starch ingredients are recovered from whole grains (and such derived products) . During the process, fats, salts, vitamins and minerals are recovered as well as a fiber rich and almost starch free bran. The process consists of a series of enzymatic treatments: an proteolytic enzyme to solubilize the protein, a starch hydrolyzing enzyme and, optionally, an iso erase to transform part of the glucose content to- fructose. Examples disclose the use of the wheat bran product in white bread and in breakfast cereal.

A known analytical technique for separating the digestible portion of dietary fiber from the ingestible portion in order to determine the dietary fiber content is outlined in a publication by the Association of Analytical Chemists - "Total Dietary Fiber: AOAC Collaborative Study, January 25, 1982". The technique involves (1) the solvent extraction of cereal bran to defat the fiber, (2) enzymatically treating the fiber with protease to remove protein, (3) then treatment with termamyl to remove carbohydrates. Sharma et al., U.S. Patent Nos. 4,619,813 and 4,565,702, utilize the analytical technique to prepare a dietary fiber composition in which an insoluble fiber is coated with a soluble fiber. The composition is incorporated into foods such as candy bars, gelatin tablets and fruit rolls. Sadaranganey et al., U.S. Patent No. 4,919,952, disclose extracting wheat millfeed with an aqueous basic solution at pH 9-11 a slurry with solvent/millfeed ratio on the range of 7:1 to 10:1 v/w; separating the alkali liquid from the millfeed residue, heating the slurry of millfeed residue to 50°-100°C and treating it with 35-70% w/v hydrogen peroxide and drying the residue to produce a light colored dietary fiber concentrate.

In Patent No. AU 88/10,740 a method is disclosed for treating oat hulls under alkaline conditions at high temperatures and pressures to obtain a product low in silica (ash) and lignin and having a high water absorbency. According to the preferred embodiment, the oat hulls are treated with aqueous NaOH, pH 11-14, for 2 hours at 150"-175^ and saturation pressure of about 65 psig. The resulting fiber is bleached using conventional bleaching technology. Satisfactory bread products were obtained when 15 to 50% of the wheat flour was substituted with the treated oat hull fiber.

The present invention discloses a simple and novel method for efficiently and economically removing the protein, ash and digestible carbohydrate coπponents frcm cereal grain brans, thereby concentrating the fiber fraction to produce non-white fiber concentrate with an increased total dietary content and a decreased ash content. The high fiber dietary product of this invention may be used in laxatives, in pharmaceutical products, as a partial substitution of regular flour in cereal, crackers, cake mixes, breads and baked goods and as a fiber additive in other food or drink products to raise fiber content and to lower caloric content. The fiber can be further bleached by conventional bleaching agents, such as H2O₂, O₃, or O₂• In addition, the base solubilized proteins can be precipitated by either heat and/or by acid as a protein concentrate which can be used as or in human food or animal feed.

SUMMARY OF THE INVENTION The present invention provides a process for concentrating the fiber fraction of cereal grain brans which comprises two steps:

1. contacting the brans at about 5° to 50^βC with an aqueous solution having a pH of about 1 to 3 for about 5 to 120 minutes, then filtering and washing the brans;

2. contacting the brans at about 5^β to 50"C with an ' aqueous base at pH 9 to 12 for about 5 to 120 minutes, then filtering and washing the brans.

The invention involves step 1 or both steps which may be carried out in any order. DETAILED DESCRIPTION OF THE INVENTION The cereal grains from which the dietary fiber may be derived include wheat, rice, corn (maize) , rye, barley, oats, sorghum, millet and triticale. This invention will allow the utilization of the cereal grain bran by-products of the flour milling processes. These by-products are low in total dietary fiber content and high in protein, ash, carbohydrate and fat content. By dietary fiber it is meant non-starch polysaccharides and lignin that are not digested by enzymes of the human gastrointestinal tract. Polysaccharides include cellulose, hemicellulose (xylan, arabinoxylan, xyloglucan, glucamannan) , pectic substances and associated polysaccharides (arabinan, arabingalacton and galactan) , as well as fruσtan, galactomannan and B-glucan.

Dietary fiber can be divided into two broad categories: insoluble dietary fiber and water soluble dietary fiber. "Insoluble dietary fiber" means insoluble, substantially non-swellable dietary fiber, while "soluble dietary fiber" is that which is water soluble or water swellable. Total dietary fiber (TDF) includes both insoluble and soluble dietary fiber. According to the invention, there is provided a dietary fiber product based on the cereal grain brans, in which the content of total dietary fiber is increased and the ash content is decreased. The process steps of the present invention may be carried out in any order which is convenient.

After the final filtering and washing is completed, the brans may be dried in a fluidized bed dryer or may be dried by any method which achieves the same result. If desired, the brans may be bleached at a convenient step in the process. The process of the present invention may be carried out in a continuous mode. For wheat bran products, the fiber content can be as high as 75 to 90 weight percent.

The reduction of protein and starch may be accomplished using any food-grade base such as sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide or airmonium. hydroxide; sodium hydroxide, potassium hydroxide or aππonium hydroxide are preferred because they are suitable for the pH adjustment in the desired range and are economical. The brans are contacted at about 5" to 50°C with an aqueous acid solution having a pH of about 9 to 12 for about 5 to 120 minutes, then filtered and washed. The temperature, pH and length of contact time can be optimized to obtain a maximal reduction of protein. The reduction of ash may be accomplished using a food-grade acid such as hydrochloric, phosphoric, sulfuric, acetic or citric acid; hydrochloric acid is preferred because it is economical and does not complicate downstream waste treatment. The brans are contacted at about 5° to 50'C with an aqueous acid solution having a pH of about 1 to 3 for about 5 to 120 minutes, then filtered and washed. The temperature, pH and length of contact time can be optimized to obtain a significant reduction of ash. For wheat bran products, the ash content can be reduced to 0.5 to 2 weight percent.

By the process of this invention, the treatment of cereal grain brans with acid and base, the ash, the protein, starch, fat and phytic acid content of the brands are reduced. Additionally, the total dietary fiber content, oil absorbency, and water absorbency are increased significantly. If a further reduction of protein is desired, the brans may be further treated with protease. Generally, the carbohydrate content is reduced to an acceptable level during the acid and base treatment processes. If a further reduction in carbohydrate content is desired, the brans may be treated with -amylase. The optional reduction of carbohydrate may be accomplished using any food-grade pH buffer solution suitable to enhance the enzymatic behavior of the λ -amylase. Likewise, the optimum temperature of the slurry is one which enhances the enzymatic behavior of the^-amylase. The enzymatic activity is allowed to proceed until the carbohydrate has been reduced to the desired level.

Another advantage of the process of the present invention is that the dietary fiber product is sterile and may be used directly in food and pharmaceutical products. Any yeast or molds present in the raw bran are effectively destroyed by the process.

In addition to concentrating the fiber fraction of cereal grains to yield a high total dietary fiber product and removing the protein and carbohydrate components to lower the caloric content of the product, phytic acid is extracted or is partially extracted in the acid step of the process. The phytic acid (C6H18O24P6, P=28.6%) content is reduced as evidenced by the reduction in the phosphorus content. The inhibiting effect of the dietary fiber on iron, calcium and zinc absorption is negligible if the phytic acid content of the dietary fiber product is 1.0% or less, by weight.

EXAMPLE 1

In Example 1, wheat brans are treated by the base process, then by the acid process.

Hastings Spring red wheat bran^'s (1000 g oven-dry wt.) were slurried in 9000 ml of potable water at room temperature. The pH of the slurry was adjusted from 6.1 to 11.1 by adding 60 g of 37% NaOH. The brans were stirred for 30 minutes at pH 11.1 and then were filtered and washed with 3 aliquots of 9000 ml of potable water.

The brans were reslurried in 9000 ml of potable water and the pH was adjusted from 9.6 to 2.0 by adding 352 g of 10.3% HCl. The pH was maintained at 2.0 for 15 minutes and then the brans were filtered and washed with 4 aliquots of 9000 ml of potable water. The pH of the fourth wash solution was 3.4. The brans were reslurried in 9000 ml of potable water and the pH was adjusted from 3.5 to 5.2 by adding 9 g of 37% NaOH. The brans were filtered, washed with 2 aliquots of 9000 ml of potable water and dried in a fluidized bed dryer at 70°C. For analysis, the brans were ground through a 20-mesh screen.

The analysis of the product, treated bran, is compared with the starting material, raw bran, in Table 1.

TABLE 1

*! Hastings Spring Red Wheat Bran

EXAMPLE 2

In Example 2, wheat brans are treated by the base process, then by the acid process.

Durum wheat brans (1092.0 g with a moisture content of 9.2%) were slurried with 9000 ml of potable water at 26°C for 15 minutes. The pH of the slurry was adjusted to 11.07 by adding 67.3 g of 36.6% NaOH. After 30 minutes of stirring at pH 11.07 the brans were filtered through a 60-mesh screen and then washed with 3 aliquots of 9000 ml of potable water.

The brans were reslurried with 9000 ml of potable water at 27°C. The pH of the slurry was -lo¬ adjusted from 9.46 to 2.01 by adding 213.0 g of 10.3% HC1. The pH was maintained at 2.01 for 15 minutes at 26°C and then the brans were filtered through a -~*s60-mesh screen and were washed with 4 aliquots of 9000 ml of potable water. The pH of the fourth wash solution was 4.28.

The brans were reslurried in 9000 ml of potable water at 26°C. The pH of the slurry was adjusted from 3.66 to 5.24 by adding 7.0 g of 36.6% NaOH. The pH was maintained at 5.24 for 15 minutes at 27°C; then the brans were filtered through a

screen, washed with 2 aliquots of 9000 ml of potable water and dried in a fluidized bed dryer at 70°C. For analysis, the brans were ground through a 20-mesh- screen.

The analysis of the product, treated bran, is compared with the starting material, raw bran, in Table 2.

TABLE 2

*² Durum Wheat Bran

EXAMPLE 3 In Example 3, wheat brans are treated with e -amylase, then by base process.

Canadian Harvest Hi-Fi white wheat brans (106.4 g oven-dry wt.) were slurried with 893.6 ml of potable water. The slurry was brought to a boil and held at that temperature for 10 minutes. The slurry was removed from the heat and allowed to cool for 50 minutes, to a temperature of 54°C. The pH of the slurry was 6.09.

The slurry was reheated to 56°C and the pH was adjusted to 5.41 by the addition of 4.3 g of 10% HC1. After stirring the bran slurry for 15 minutes, 10 ml of asperzyme (pH of asperzyme liquid was 5.99) was added. The temperature of the slurry was maintained at 56"C, while stirring, for 4 hours. The pH of the slurry was 5.39.

The brans were filtered through a

screen and were washed with 500 ml of potable water. After overnight refrigeration, the brans were reslurried to 1000 g with potable water. The pH was adjusted to 9.14 with 1.7 g of 35.6% NaOH, then stirred for 20 minutes at 26 " C .

After filtering through a <~60-mesh screen and washing with 2 aliquots of 1000 ml of potable water, the brans were reslurried to 1000 g with potable water. The pH was adjusted from 8.58 to 5.43 with 3.7 g of 10% HC1. After 15 minutes at that pH, the brans were filtered through a ^60-raesh screen and washed with 2 aliquots of 1000 ml of potable water. The brans were placed in a fluidized bed dryer at 70^βC for 20 minutes. For analysis, the brans were ground through a 20-mesh screen.

The analysis of the product, treated bran, is compared with the starting material, raw bran, in Table 3.

*³ Canadian Harvest Hi-Fi White Wheat Bran

EXAMPLE 4

Treated Hastings Spring red bran fibers from Example 1 (fiber A) and treated Durum wheat bran fibers from Example 2 (fiber B) were tested as a partial replacement for flour in bread. For comparison, Canadian Harvest Snowite oat fibers (fiber C) , which had been bleached by alkaline Tydrogen peroxide solution, were used as the standard. The bread flour used was Buccaneer wheat flour.

The baking results are tabulated in Table 4. The standard lite fiber bread with a 40% replacement of fiber C had a baking score of 82 and an internal structure similar to white pan bread. The dough with 20% fiber A and 20% fiber C gave a nice loaf of bread, similar in appearance to whole wheat bread, with good grain and eye appealing color. The 40% fiber A dough was slightly dry and rough which might have brought the volume down to 1850 cc. The bake score was 80 due to the decrease in volume. The 20% fiber B, 20% fiber C and the 40% fiber B doughs were extremely sticky and difficult to handle. The loaves of bread lacked volume and had a very dense internal structure; they both scored a very poor 60.

TABLE 4 Flour Replaced Baking Volume

Fiber (cc) Score Appearance

2175 82 white pan bread 1950 81 whole wheat bread

1850 80 dark rye bread poor 60 dense structure

poor 60 dense structure

EXAMPLE 5

In Example 5, wheat brans are treated by the acid process, then by the base process.

Hastings Spring red wheat brans (111.8 g) were slurried with 900 ml of potable water at 24^βC, stirring for 10 minutes. The pH of the slurry was adjusted from 6.46 to 2.03 by the addition of 15.33 g of 20.38% HC1. After stirring for 15 minutes the brans were filtered through a **-•60-mesh screen and washed with 3 aliquots of 900 ml of potable water. The brans were reslurried to 1000 g with potable water and the pH was adjusted from 3.56 to 11.07, at 24°C by the addition of 4.3 of 35.02% NaOH. After stirring for 30 minutes, the brans were filtered through a ^-^60-mesh screen and washed with 4 aliquots of 900 ml of potable water. The pH of the fourth filter solution was 8.87. The brans were reslurried to 1000 g with potable water and the pH was adjusted from 9.63 to 6.52 by the addition, at 23^<>C, of 2.48 g of 10.0% HC1. After stirring for 15 minutes the brans were filtered through

screen and washed with 2 aliquots of 900 ml of potable water. The brans were placed in a fluidized bed dryer at 70°C for 20 minutes. For analysis, the bran product was ground through a 20-mesh screen. The analysis of the product, treated bran, is compared with the starting material, raw bran, in Table 5.

EXAMPLE 6 In Example 6, wheat brans are treated by the base process, then by the acid process, and finally with ^, -amylase.

Hastings Spring red wheat brans (223.6 g) were slurried with 1800 ml of potable water at 24"C, stirring for 15 minutes. The pH of the slurry was adjusted from 6.50 to 11.09 by the addition of 10.47 g of 35.02% NaOH. After stirring for 30 minutes at 25"C the brans were filtered through —s60-mesh screen and washed with 3 aliquots of 1800 ml of potable water. The brans were reslurried to 2000 g with potable water and the pH was adjusted from 9.95 to 2.02 by the addition of 23.67 g of 20.38% HC1. After stirring for 15 minutes at 24°C, the brans were filtered through ■—' 60-mesh screen and washed with 4 aliquots of 1800 ml of potable water.

After overnight refrigeration the brans were reslurried to 2000 g with potable water. The slurry was heated to 56°C, via a water bath, and the pH was adjusted from 3.94 to 5.46 by the addition, at 55.7°C of 1.42 g of 35.02% NaOH. After the addition of 5 ml of asperzyme the slurry was maintained at a pH of 5.4 and a temperature of 56°C for 4 hours.

The brans were filtered through a

screen and washed with 2 aliquots of 1800 ml of potable water. The brans were placed in a fluidized bed dryer at 70°C for 40 minutes. For analysis, the bran product was ground through a 20-mesh screen.

The analysis of the product, treated bran, is compared with the starting material, raw bran, in Table 5.

EXAMPLE 7 In Example 7, wheat brans are treated by the base process, then by the acid process and finally with protease.

Hastings Spring red wheat brans (223.6 g) were slurried with 1800 ml of potable water at 24°C, and stirred for 15 minutes. The pH of the slurry was adjusted from 6.45 to 11.06 by adding 10.55 g of 35.02% NaOH. The brans were stirred for 30 minutes at 25*C and then were filtered through ■~'60-mesh screen and washed with 3 aliquots of 1800 ml of potable water.

The brans were reslurried to 2000 g with potable water at 24"C and the pH was adjusted from

10.07 to 2.01 by adding 23.04 g of 20.38% HC1. After stirring for 15 minutes at 24^βC, the brans were filtered and washed with 4 aliquots of 1800 ml of potable water. After overnight refrigeration the brans were reslurried to 2000 g with potable water and heated to 50°C, via a water bath. The pH was adjusted from 3.87 to 7.08 by adding 2.70 g of 37.02% NaOH. After the addition of 0.0639 g of Enzeco^® neutral bacterial protease in a 10 ml pH 7.0 buffer solution, the slurry was stirred for 4 hours at 50°C; the pH of the slurry was maintained at 7.0.

The brans were filtered hot through a --- 60-mesh screen and washed with 2 aliquots of 1800 ml of potable water. The brans were placed in a fluidized bed dryer at 70°C for 40 minutes. For analysis, the bran product was ground through a 20-mesh screen.

* Raw Hastings Spring Red Wheat Bran *⁵ Treated Hastings Spring Red Wheat Bran, Ex. 5 *⁶ Treated Hastings Spring Red Wheat Bran, Ex. 6 *⁷ Treated Hastings Spring Red Wheat Bran, Ex. 7 Std. = Standard; neg. = negative.

EXAMPLE 8 In Example 8, rice brans were treated by the acid process. Raw rice brans (218.6 g)_. were slurried with

1000 ml of 2-propanol and were brought to reflux temperature, 83'C. After 30 minutes of reflux, with stirring, the hot brans were filtered through a r — 60-mesh screen and then were washed with 8 aliquots of 1000 ml of process water.

The brans were reslurried to 1000 g with distilled water. The pH was adjusted from 6.75 to 2.02, at 24"C, by the addition of 74.13 g of 10.0% HC1. After stirring for 15 minutes the brans were filtered through a -_*- 60-mesh screen and then were washed with 2 aliquots of 1000 ml of process water. The pH of the eighth wash solution was 5.51. The brans were dried in a fluidized bed dryer at 70"C for 30 minutes. For analysis, the brans were ground through a 20-mesh screen.

The analysis of the product, treated bran, is compared with the starting material, raw bran, in Table 6.

EXAMPLE 9

In Example 9, rice brans were treated by the acid process, then with -amylase.

Raw rice brans (218.6 g) were slurried with 1000 ml of 2-propanol and were brought to reflux temperature, 83°C. After 30 minutes of reflux, with stirring, the hot brans were filtered through a ,--_^60-mesh screen and then were washed with 2 aliquots of 1000 ml of process water.

The brans were reslurried to 1000 g with distilled water. The pH was adjusted from 6.84 to 2.02, at 23°C, by the addition of 74.30 g of 10.0% HC1. After stirring for 15 minutes the brans were filtered through a -^^60-πιes screen and then were washed with 2 aliquots of 1000 ml of process water. After overnight refrigeration, the brans were reslurried to 1000 g with process water. The slurry was heated to 55°C and the pH adjusted from 3.85 to 5.49 by the addition of 2.04 g of 34.55% NaOH. By pipette, 5 ml of asperzyme was added to the slurry? the slurry was maintained at a pH of 5.4 and a temperature of 55°C for 4 hours. The hot brans were filtered through a ^-—'60-mesh screen, washed with 2 aliquots of 1000 ml of process water and then dried in a fluidized bed dryer at 70°C for 30 minutes. For analysis, the brans were ground through a 20-mesh screen.

EXAMPLE 10

In Example 10, rice brans were treated by the acid process, then with t -amylase, and finally with protease.

Raw rice brans (218.6 g) were slurried with 1000 ml of 2-propanol and were brought to reflux temperature, 83°C. After 30 minutes of reflux, with stirring, the hot brans were filtered through a

.^-60-mesh screen and then were washed with 2 aliquots of 1000 ml of process water. The brans were reslurried to 1000 g with distilled water. The pH was adjusted from 6.75 to 2.02, at 23°C, by the addition of 74.04 g of 10.0% HCl. After stirring for 15 minutes the brans were filtered through a .~--s60-mesh screen and then were washed with 2 aliquots of 1000 ml of process water. After overnight refrigeration, the brans were reslurried to 1000 g with process water. The slurry was heated to 55°C and the pH adjusted from 3.89 to 5.55 by the addition of 2.16 g of 34.55% NaOH. By pipette, 5 ml of asperzyme was added to the slurry; the slurry was maintained at a pH of 5.4 and a temperature of 55°C for 4 hours. The hot brans were filtered through a -_-/60-mesh screen, wa-shed with 2 aliquots of 1000 ml of process water.

After overnight refrigeration the brans were reslurried to 1000 g with process water. The slurry was heated to 50"C and the pH adjusted from 6.04 to 7.06 by the addition of 0.58 g of 34.55% NaOH. A 10 ml pH 7.0 buffer solution containing 0.1013 g of Enzeco^® neutral bacteria protease was added to the slurry; the slurry was maintained, stirring, at a pH of 7.0 and a temperature of 50°C for 4 hours.

The hot brans were filtered through a 60-mesh screen, washed with 2 aliquots of 1000 ml of process water, then dried in a fluidized bed dryer at 70°C for 30 minutes. For analysis, the brans were ground through a 20-mesh screen.

The analysis of the product, treated bran, is compared with the starting material, raw bran, in Table 6. TABLE 6

* Rice Bran

*⁸ Rice Bran, Example 8

*⁹ Rice Bran, Example 9

*¹⁰ Rice Bran, Example 10

Claims

CLAIMS :

1. A process for concentrating and increasing the water absorbency of the fiber fraction of cereal grain bran comprising contacting said bran with an aqueous acid solution at pH 1 to 3 at about 5° to 50°C for a period of about 5 to 120 minutes, then filtering and washing the bran.

2. The process of Claim 1, wherein the bran also is treated with a basic aqueous solution at pH 9 to 12, at 5° to 50°C, for about 5 to 120 minutes, then filtered and washed.

3. The process of Claim 2, wherein the bran is first treated with the basic solution, washed, filtered and then treated with the acidic solution and washed.

4. The process of Claim 3,wherein the pH of the acid treated bran is raised slightly and while still acidic the bran is treated with an aqueous solution of α-amylase, and then filtered and washed.

5. The process of Claim 3, wherein after the acid treatment the bran is washed and filtered, the pH adjusted to about 7 and treated with protease.

6. The process of Claim 2, wherein the bran is first treated with the acidic aqueous solution, washed and filtered and then treated with the basic aqueous solution.

7. The process of Claim 1, wherein the bran is a cereal bran selected from the group consisting of wheat, rice, corn, oat and barley brans.

8. The process of Claim 7, wherein the acid treated bran is treated with α-amylase.

9. The process of Claim 8, wherein the bran after treatment with α.-amylase is treated with protease.

10. The process of Claim 7, wherein the acid treated bran is treated with protease.

11. A wheat bran product containing from 75 to 95 weight percent fiber and from 0.5 to 2.0 weight percent ash.

12. The wheat bran product of Claim 11, wherein the phytic acid content is less than 1.0 weight percent.