WO2000030457A9

WO2000030457A9 - Enzymatic preparation of cereal base

Info

Publication number: WO2000030457A9
Application number: PCT/US1999/027389
Authority: WO
Inventors: Kenneth Lewen; Daniel Fletcher; Robin S Dickmann; Guoshen Yang; James B Holder; Lori A Wilson; Michael R Andrews; Keswara R Vadlamani
Original assignee: Kellog Co
Priority date: 1998-11-20
Filing date: 1999-11-18
Publication date: 2001-05-17
Also published as: WO2000030457A1; AU1736200A

Abstract

Oat-derived non-dairy base prepared by enzymatically digesting a slurry of oats with an enzyme that generates glucose from the oat starch.

Description

ENZYMATIC PREPARATION OF CEREAL BASE

FIELD OF THE INVENTION

The present invention is directed to production of a cereal base having a high beta-glucan content, foods and beverages including the base, and methods for preparing the cereal base. The cereal base is prepared digesting a cereal substrate that contains beta-glucan with an enzyme or enzyme mixture that break down starch, wherein the resulting enzyme or enzyme mixture does not have substantial activity to break the beta- 1 ,4-glycosidic bonds found in fiber, to produce the cereal base. The cereal base may then be further processed to yield a concentrate or a dry product or may be directly incorporated with other ingredients to yield the desired final product. Preferably the cereal substrate is oats or a derivative of oats.

BACKGROUND AND SUMMARY OF THE INVENTION

Dietary fiber has many health benefits, and is known to aid digestion, reduce serum cholesterol, and has been shown to reduce the risk of other conditions and diseases, e.g. heart disease, diverticulitis, ulcers, and colon cancer (Burkitt et al. Lancet 2: 1408-1411, 1972). Reduction of total serum cholesterol is very important, since hypercholesteolemia is one of the three major risk factors for ischemic heart disease and there is a strong positive correlation between blood cholesterol levels and the risk of heart disease. Beta-glucan is a soluble fiber with a proven cholesterol lowering effect. Beta-glucan is commonly found in grains such as barley and oats, yeast cell walls, and other natural sources. Certain grains, particularly oats, have a naturally high beta-glucan content, making them an excellent source of beta-glucan. Thus, coronary heart disease (CHD) is a major public health concern in the United States and it accounts for more deaths than any other disease or group of diseases. Early management of risk factors for CHD is a major public health goal that can assist in reducing the occurrence of CHD. Scientific evidence demonstrates that the addition of soluble fiber from certain foods to a diet that is low in saturated fat and cholesterol may help reduce the risk of CHD. The U. S . Food and

Drug Administration has authorized the use of a health claim for foods that are high in oat bran and oatmeal and low in saturated fat and cholesterol. The U.S. FDA concluded that a daily intake of not less than 40 g of oat bran or 60 g oatmeal (providing 3 g or more per day of β- glucan soluble fiber) is associated with reduced risk of coronary heart disease. Trowell (Am. J. of Clin. Nutr. 25: 464-465, 1972) reported that diets deficient in dietary fiber contribute to ischemic heart disease. A number of studies by several researchers (Anderson and Chen, Am. J. Clin. Nutr. 32: 346, 1979; Judd and Truswell, pp 23-39 in: Dietary Fiber Perspective A.R. Lees ed.; Nan Horn et al., J. Am. DietAssoc. 86: 759, 1986) have shown that the consumption of soluble fiber can lower serum cholesterol in humans. The U.S. FDAhas stipulated guidelines for sources of β-glucan soluble fiber that meet the health claim requirement. Oat bran, rolled oats, and whole oat flour are three allowed sources of β-glucan soluble fiber. All three materials will meet the FDA health claim requirement, provided that the contents of β-glucan and total dietary fiber (TDF) of the raw material is at least 5.5% and 16% (dry weight basis (dwb)) respectively for oat bran, or at least 4 and 10% (dwb) respectively for both rolled oats and whole oat flour. Food products prepared from the above qualifying whole oat sources and having 0.75g or more of β-glucan soluble fiber per reference serving amount may be labeled to indicate that the product may help reduce the risk of coronary heart disease. However, suitable beverages, and many other food products meeting this requirement are difficult to prepare because the ins oluble fiber in the oats yields a gritty product.

Additionally, it is difficult to achieve the required β-glucan content in foods other than baked goods, or those having large reference serving sizes due to the relatively low concentration of β-glucan soluble fiber in oats relative to their starch content, resulting in a "pasty", or " starch- textured" product. Oats also have a distinct "oaty" aroma and flavor that is not compatible with many commonly consumed food products and this aroma and flavor become distinctive at higher levels of oat content. Furthermore, oats have a high content of native lipase and oil that is susceptible to oxidative rancidity and this characteristic adversely affects the shelf-life of convenience foods prepared with high levels of oat. The protein component of oats can produce a bitter flavor and an undesirable opacity in certain foods such as beverages.

U.S. Patent No. 4,996,063 to Inglett discloses a method to prepare water-soluble dietary fiber compositions. The process involves treating an aqueous dispersion of a gelatinized, milled, oat substrate, e. g. oat flour, with a thermostable α-amylase under conditions which hy drolyze the oat substrate and yield soluble and insoluble fractions. The soluble fraction comprises soluble oat fiber and maltooligosaccharides, and the insoluble fraction contains a high proportion of protein as well as insoluble fiber. The enzyme is then inactivated, e.g. by passing the mixture through a steam injection cooker at a temperature of 140°C, or by acidification. The soluble fraction is then separated from the insoluble fraction by centrifugation, and the water-soluble dietary fiber is recovered from the soluble fraction, e.g. by removing the water. This material does not qualify to make the FDA health claim regarding the reduction of coronary heart disease because it is lacking in insoluble fiber.

U.S. Patent No. 4,377,602 to Conrad describes a hydrolyzed protein and starch product prepared, in situ, by enzymaticaUy hydrolyzing protein and starch products from whole grain. Whole grain is crushed in order to expose the endosperm and thereafter the crushed grain is subjected to enzymatic treatment with an endopeptidase in an aqueous medium to transform water-ins oluble proteins to water-s oluble protein products . The water-ins oluble protein products are then filtered and recovered. The remaining crushed grain is then treated with (α-amylase in an aqueous medium followed sequentially by an amyloglucosidase, so as to transform substantially all of the water-insoluble starch fractions in the grain to glucose. This material also does not qualify to make the FDA health claim regarding the reduction of coronary heart disease because it is lacking in insoluble fiber.

In Food Technology, 45 (6) 104 (1991) Inglett et al. describe a product, Oatrim, a maltodextrin made from oats that is reported to provide a high beta-glucan content and is used as a fat replacer. Oatrim is reported to have a serum cholesterol-lowering effect and is prepared by converting oat starch to maltodextrin with a thermo-stable α-amylase (U. S. PatentNo.4, 996 063).

To date, Oatrim has not qualified to make the FDA health claim regarding reduction of coronary heart disease because it is lacking in insoluble dietary fiber. European PatentNo.231 729 B 1 discloses aprocess for manufacturing foodstuffs starting from whole flour of a starch containing cereal grain. The whole grain flour may be derived from oats and is then suspended in water containing 40-150 ppm calcium ions. The process described in this European patent includes the sequential treatment of grain flour first with α-amylase and then with beta-amylase. The resultant liquid can be used to make beverages. One embodiment in EP 729 is directed to aprocess pre-treating a barley-based flour with beta-glucanase to reduce viscosity prior to treatment with alpha-amylase. The treatment with beta-glucanase will alter the structure of β-glucan and destroys its intended physiological properties, rendering the material unqualified for the U.S. FDA health claim. U.S. Patent No. 5,686,123 to Lindahl et al. discloses a method to prepare an oat based cereal suspension containing intact beta-glucans by suspending dry- or wet-ground rolled oats or otherwise heat-and water-treated oats, optionally centrifuging or decanting the suspension to remove coarse fiber particles. The suspension depleted in fiber is then treated first with a beta- amylase and then subsequently with an alpha-amylase, each enzyme step being performed to achieve a specific endpoint determined by viscosity. The suspension is then homogenized and subjected to an ultra high temperature (UHT) treatment to inactivate the added enzymes and obtain a sterile product. This material do not qualify to make the FDA health claim regarding the reduction of coronary heart disease because it is lacking in insoluble fiber.

Enzymatic treatment of cereal grains has also been used to make fat substitutes, such as described in U.S. PatentNo. 5,912,031 to Fitchett et al. Fitchett et al. describe preparation of a fat replacer by enzymatic digestion of a ground cereal with alpha-amylase by forming an aqueous slurry of ground cereal, the slurry having a dry solids content of 10 to 50 weight percent; enzymaticaUy digesting the slurry at 60-95° C with an alpha-amylase enzyme capable of being deactivated by temperatures below 100 °C, whereby the enzymatic digestion is effected without any significant protein degredation, and thermally deactivating the alpha-amylase enzyme. The products of the process are reported to be useful as fat replacers in a wide variety of foods, including baked goods, dairy products, and meat products.

Despite these different approaches, it remains difficult to provide a beverage or food having a relatively high beta-glucan content while maintaining the total dietary fiber content intact, without strong "oaty" taste or smell. Also, the products produced in prior art do not qualify for U.S. FDA health claims as the insoluble fiber is removed during these processes.

Thus, there is a real and unsatisfied need in the art for an improved method to produce a concentrated form of wholesome cereal grain product rich in beta-glucan as well as total dietary fiber. These objects are achieved by the present invention, which relates in part to a cereal base having on a dry-weight basis (dwb), a beta-glucan content of from about 5 to 25%, and preferably a total dietary fiber content of from about 10% to 50%. It is preferred that the cereal base and final products prepared therefrom qualify to make the coronary heart disease health claim according to the proscriptions of the U.S. Food and Drug Administration. In preferred embodiments, the invention is directed to a method of preparing an oat base by preparing an aqueous slurry containing 5 to 45% oat substrate on a dry weight basis and treating the slurry with an enzyme, e.g., alpha-amylase, having substantially no beta-glucanase activity to hydrolyze the starch. The oat substrate may be completely or partially gelatinized before or after introduction of the enzyme. Gelatinization may be accomplished by, e.g., heating the slurry to a temperature sufficient to gelatinize at least a portion of the starch. The enzyme treatment continues until the desired endpoint is reached, and the enzyme is then inactivated, e.g. , by heating or adjusting the pH of the slurry. The resulting product is a cereal base rich in beta- glucan which can be directly incorporated with other ingredients to form the final edible product, typically a food or beverage. Any enzymes that are capable of breaking down starch to dextrins, maltose, glucose, or any combination of these final products can be used. The enzymes are preferably free or substantially free of enzymes that break down beta-glucan, such as beta-glucanase. Preferred enzymes include thermo-stable alpha-amylases stable at temperatures greater than 100° C, moderately thermo-stable alpha-amylase, heat-labile alpha-amylase, isoamylases and amyloglucosidases.

The resultant cereal base may be further processed, e.g., by dehydrated sufficiently to yield a liquid concentrate or a solid.

The invention is described in further detail below.

DETAILED DESCRIPTION OF THE INVENTION

To prepare the cereal base of the present invention, referred to as "oat base" hereinafter, an aqueous slurry of oat substrate is prepared by admixing an aqueous fluid or an emulsion having an aqueous component, e.g. water or milk, with an oat substrate containing beta-glucan. The oat substrate may be, e. g. , whole grain oats, rolled oats , oat bran, oat flour, or the like. Other grain substrates having a beta glucan content, such as barley, may also be used, but oat substrates are preferred. It is preferred that the oat source is a qualifying oat source in order to make the U.S. FDA approved health claim regarding reduction of the risk of coronary heart disease, or a corresponding claim in a given country . Preferably the oat s ource is an oat material that has been pre-heat treated in order to inactivate the native enzymes, for e.g. lipase. A preferred oat substrate is milled to an average particle size of less than 500 microns. Preferably the average particle size ranges between 20 to 200 microns.

A particularly preferred oat substrate is an oat substrate that is subjected to one or more techniques that will separate the oat fraction rich in soluble and insoluble fiber from the oat fraction that is poor in soluble and insoluble fiber, yielding a fraction that is relatively higher in beta-glucan content. Suitable techniques for preparing an oat substrate fraction having a relatively high beta-glucan content include, but are not limited to sieving and air classification. The amount of beta-glucan in such fractionated oats typically ranges from 5 to 25% by weight, and preferably from 15 to 20% by weight beta glucan. It will be recognized that variations outside these ranges will occur due to many factors, including the starting content of beta-glucan in the starting oat substrate. It is contemplated that genetically engineered oats or cereal grains may be developed that will have a higher content of beta-glucan than in presently available sources, and it is anticipated that these will be suitable for use within the scope of the present invention.

A particularly preferred oat substrate is oat bran that has been milled to an average particle size below 500 microns, and has been fractionated via air classification to remove the less dense particles and increase the percent soluble and insoluble fiber in the oat bran. The final particle for the oat substrate depends on the final use. For example, beverages require a relatively small particle size, e.g. less than 75 microns. Baked goods typically do not have a particle size limitation, and oat bran that has been air classified without additional milling may be used.

The slurry preferably contains 1 to 45 wt. % oat substrate, preferably 15 to 25 wt. %. The substrate may be added all at once prior to addition of the enzyme, or may be added stepwise, allowing for partial or complete enzyme digestion prior to incorporation of additional portions. After the slurry is prepared it is treated with the enzyme to hy drolyze the starch in the oat substrate. The oat substrate may be gelatinized either prior to or after the addition of the enzyme, e.g., by raising the temperature of the slurry for a sufficient period of time to gelatinize the starches. Typically, a temperature above 65°C is maintained, preferably a temperature of 85 to

90°C for about 5 to 10 minutes. If gelatinization is conducted prior to addition of the enzyme, the slurry may be cooled before the enzyme is added.

Any enzyme or mixture of enzymes capable of breaking down starch typically to dextrins, maltose, or glucose and that does not exhibit substantial activity, and preferably exhibits no activity for the breaking of beta-l,4-glycosidic bonds found in fiber can be used. This is important because several available enzymes contain other enzymes, which can be characterized as impurities, that exhibit such activity and would hydrolyze beta-glucan, decreasing the beta- glucan content of the cereal base. An alternate method is to heat use thermostable enzymes that may have activity for breaking down the beta-l,4-glycosidic bonds, but the slurry or liquid is heated to a high enough temperature to inactivate the enzymes or contaminants responsible for the degradation of the fiber, but not to inactivate the desired enzyme or enzymes. The preferred enzymes include thermo-stable alpha-amylases (typically stable at temperatures greater than 65 °C), heat-labile alpha-amylase, beta-amylase, isoamylases and amyloglucosidases. It is anticipated that heat-stable amyloglucosidases will become available in the future and this enzyme will be preferred for breaking down starch to glucose with the use of a single enzyme and a gelatinization step.

A non-limiting list of enzymes which may be used in accordance with the present invention include G-Zyme® G995E and G990 (Enzyme Bio-systems Ltd.); Termamyl 120L Type L (Novo Nordisk); Maltogenase 4000L (Novo Nordisk); Canalpha 600,00L and 60P (Quest International); Fungamyl 800L (Novo Nordisk); AMG 300L (Novo Nordisk); and other variations of these enzymes.

G-zyme G995-E is also a thermostable alpha-amylase derived from Bacillus stearothermophilus. G995-E is most active between pH 5.0 and 7.0 and at temperatures as high as 108°C. While G-zyme G990 is a glucoamylase produced extracellularly from Aspergillus niger. G990 can hydrolyze both the alpha- 1,6 and alpha- 1,4 glucosidic bonds of starch.

Termamyl 120L, Type L, is a thermostable alpha-amylase produced by a genetically modified Bacillus licheniformis . This enzyme is an endoamylase, which randomly hydrolyzes 1 ,4-alpha-glucosidic linkages in amylose and amylopectin of starch, and rapidly converts the starch to soluble dextrins and oligosaccharides.

A particularly preferred alpha-amylase is Maltogenase 4000LO commercially available from Novo Nordisk. This enzyme is a moderately heat-stable thermostable maltogenic alpha- amylase derived from Bacillus stearothermophilus expressed in and produced by a genetically modified strain of Bacillus subtilis . The optimal activity level for Maltogenase is between 55 and 75°C and may be inactivated at 95°C for 15 minutes.

Another preferred enzyme is Canalpha 60P (powder) and 600,000L (liquid) from Quest

International are the same enzyme but in different forms and strengths. This enzyme is a thermostable bacterial alpha-amylase derived from fermentation with aselectedstrain of Bacillus subtilis. The optimal activity level is between about 65 and 85 °C and may be inactivated at 95 °C for 15 minutes.

Fungamyl 120L is a fungal alpha-amylase obtained from a selected strain of Aspergillus oryzae. This enzyme hydrolyzes the alpha- 1,4 glucosidic linkages of starch and a prolonged reaction results in the formation of large amounts of maltose.

AMG is an exo-l,4-alpha-D-glucosidase referred to as a glucoamylase or amyloglucosidase AMG is obtained from a selected strain of Aspergillus niger by submerged fermentation. This enzyme hydrolyzes both the 1 ,4 and 1 ,6-alpha linkages in starch, and removes glucose units in a stepwise manner from the non-reducing end of the starch molecule.

Other enzymes derived from these and other sources are expected to be acceptable for use in accordance with the present invention, and the aforementioned enzymes are mentioned solely as preferred enzymes.

The amount of enzyme added and the reaction time for the enzyme is determined, inter alia, by the desired texture of the final product and the percentage of grain solids, e.g. oat bran or barley flour, in the mixture.

Optionally, a suitable calcium source may be added to stabilize the enzyme. Typically, from about 20 to 50 ppm Ca++ is added and the amount is dependent on the processing conditions and the type and amount of enzyme used. Another option, is that sucrose in amounts of from 1 to 10%) by weight can be added to the enzyme prior to addition to the heated water or slurry. The sucrose can be dry mixed with the enzyme or added to a liquid enzyme. After preparation of the slurry, the enzyme digestion of the starch is continued until the desired products and viscosity are obtained. Preferably, the temperature is maintained or steadily raised to between 55 and 85°C for about an 1 hour and usually less than 25 minutes. The temperature is then raised for a sufficient length of time to gelatinize the starch, a temperature above 65°C is maintained, preferably a temperature of 85 to 90°C for about 5 to 10 minutes. These lengths and temperatures may be less than 1 minute and greater than 6 hours depending on the conditions of the slurry and enzyme used.

After gelatinization, the slurry may optionally be cooled for the addition of the same enzyme(s) or different enzyme be added, and digestion may then be continued to reach the desired endpoint. Preferably, the enzymes are inactivated by an appropriate method which depends upon the final use of the product. Methods of enzyme deactivation include heating, pH adjustment, and spray drying. For the preferred enzymes, temperatures in excess of 95 ° C for 10 minutes are generally sufficient to inactivate the enzymes. High temperature and short time inactivation can be achieved by several methods including jet cooking, preferably at temperatures between 138 and 176 ° C and ultra-high temperature (UHT) processing, preferably at 137 to 144°C for 2 to 10 seconds.

If the product is to be dried, any number of drying techniques can be used, but it is preferred to use a technique that will also inactivate the enzymes, such as spray drying. It is preferred that the dried cereal base is in a powder form. In a preferred embodiment, the resulting liquid cereal base is subjected to high shear forces by using equipment such as ahomogenizer, microfluidizer^® (MFIC Corporation), and jet cooker. Homogenization is carried out under suitable conditions, preferably at temperature of 55 to 70°C at pressures of 500/3500 to 1000/5000 psi.

The resultant oat base will have a minimum total dietary fiber content of between 10 and 30%_> (dwb), and a beta-glucan content of at least 4%, preferably at least 5%.

In a preferred embodiment, the oat base is prepared by heating water to a temperature of from 70 to 95 °C, adding an enzymaticaUy effective amount of a thermostable alpha-amylase, adding from about 10 to about 30% by weight of a grain containing beta-glucan, e.g. oat bran or barley flour, cooling, adding other drink ingredients such as fruit and flavorants, preheating the mixture to a temperature above 65 °C, and subjecting the mixture to an ultra high temperature step at a temperature of from 138 to 176°C, and optionally homogenizing the mixture to the desired consistency.

An important feature of the processes of the present invention is that removal of the insoluble solids is not required as with prior art processes.

Preferably, the product is prepared as a dry solid by removing the water from the enzyme digested oat-liquid to yield a dry solid. This may be accomplished, e.g., by spray drying, drum drying or evaporation.

The oat base can be used in either liquid or solid form for use in a variety of food products, including, but not limited to baked goods, cereals, and preferably beverages.

Preferably the resultant food will qualify under FDA rules for a cholesterol lowering claim and therefore, whether the product is used as a liquid or solid, the product is preferred to contain 0.75 g of beta-glucan per RACC serving.

To prepare final products, the oat base is mixed with other food ingredients such as flavors, colorants and the like and are finally prepared according to art-known techniques. For beverages, it is preferred to directly use the enzymaticaUy treated slurry as the oat base.

The present invention also relates to treating hypercholesterolemia in a patient by administering a sufficient amount of the oat base or a food containing the oat base. Treatment includes aiding in the control of, or alleviating the effects associated with hypercholesterolemia, including reducing the risks or effects of coronary artery disease.

The following examples are illustrative of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Example 1

Fine Oat Bran (25.7 lbs, 6.7% β-glucan and 15.8% TDF (dwb)) was added to water (94.3 lbs, 130° F) containing calcium (100 ppm per gram of starch) and Fungamyl (15units/g starch) and Amyloglucosidase (5 units/g starch) such that the solids content was 20%, and pH of slurry 6.3. The fine oat bran has a mean particle size of 48 μm with 50% of material <30 μm and 90% <118 μm. This oat material was added to water that contained starch hydrolyzing enzymes at a constant rate (l/7^th every 5 minutes over 30 min period) such that, at no point of time, the viscosity of the slurry was excessively high. The slurry was maintained at atemperature of 131 °F and the hydrolysis continued for another 20 minutes (total time; 1 hour) and the viscosity of resultant slurry was between 6 and 360 cp. The slurry was then heated to about 185°F to gelatinize the partially hydrolyzed oat starch. The viscosity of the resultant liquid was between 75 and 6,000 cp during gelatinization. The slurry was then cooled to about 131 ° F, and a second batch of the same enzymes (in the same ratios) were added to the slurry. This enzyme treatment was continued for ~30 minutes at 131 °F until the viscosity of the liquid reached about 100 to 125 cp. This twice-enzyme treated slurry was then heated to 170°F for 20 minutes to inactivate the enzymes. The slurry was then homogenized twice by passing through a Gaulin Homogenizer at 1,000/5,000 psi, and spray dried with conventional equipment (inlet 365°F, outlet 203°F) to yield a powdery oat based substance.

Example 2

In this example, Fine Oat Bran (11.1 lbs, 6.7% β-glucan and 15.8% TDF (dwb)) was added to water (88.9 lbs, 130°F) containing 100 ppm calcium such that the solids content was 10%) andpH of the slurry 6.3. The slurry was heated to about 185°F to gelatinize the starch. The viscosity of the resultant liquid was between 300 and 105,000 cp during gelatinization. The slurry was then cooled to 131 °F andFungamyl (30 units/g of starch) and Amyloglucosidase (10 units/g of starch) were added to the slurry. The enzyme hydrolysis was continued for -40 minutes at 131 °F until the viscosity of the liquid reached about 25 - 40 cp. Then, the temperature of slurry was brought up to 170 °F and held for 20-30 minutes to inactivate the enzymes. The slurry was homogenized twice at 500/3 000 psi and spray dried (inlet 365°F and outlet 203 °F) to yield a powdery oat-based substance.

Example 3

Concentrated Oat Bran (26.7 lbs, 14.0% β-glucan and 31.8% TDF (dwb)) was added to water (93.3 lbs, 130°F) containing 100 ppm calcium and Amyloglucosidase (40 units/ g of starch) such that the solids content was 20% and pH of the slurry 6.3. The mean particle size of concentrated oat bran was 80 μm with 50% of material < 83 μm and 90% < 180 μm. The oat material was added to water that contained starch hydrolyzing enzyme at a constant rate ( 1/7* every 5 minutes over 30 min period) such that, at no point of time the viscosity of the slurry was excessively high. It was observed that the oat materials that contain high amounts of β-glucan build excessively high viscosities and is important to keep the viscosity down for ease of processing. The hydrolysis was continued for another 20 minutes and the viscosity of the resultant liquid was between 10 and 2600 cp. The slurry was heated to about 185 ° F to gelatinize the starch and the viscosity was between 250 and 6,000 cp during gelatinization process. The slurry was then cooled to 131 ° F and Amyloglucosidase (40 units/ g of starch) were added to the slurry and the hydrolysis continued for ~ 30 minutes at 131 °F until the viscosity of the liquid reached about 125 - 150 cp. Then, the temperature of slurry was brought up to 170°F and held for 30 minutes to inactivate the enzymes. The slurry was homogenized twice at 500/3 000 psi and spray dried (inlet 356°F and outlet 203 °F) to yield a powdery oat-based substance.

Example 4

In this example, Fine Whole Oat Flour (4.6% β-glucan and 15.7% TDF (dwb)) at 20% solids was used as a starting raw material and processed exactly as described in Example 1. The mean particle size of raw whole oat flour was 26 μm with 50%) of material < 17 μm and 90% < 60 μm. The chemical characteristics and particle size distribution of finished spray-dried oat materials produced in Examples 1 through 4 are given in Table I. The results in the table demonstrate that there was no or very little loss of beta-glucan and total dietary fiber content in the finished material

Table I.

Moisture β-glucan TDF Suε ;ar Profile Particle Size

Distribution

(Reconstituted)

Sam (^•/.) (% b) (%db) Glucose F Maltose Sucrose Mean 50% 90% pie ructose

(%) ( (%) (%) (μm) (μm) (μm) %)

Fine 3 ₈8 6 56 15 81 40 60 0 3 51 0 71 37 22 96

Oat Bran 33

Con 4 55 14 56 27 66 27 10 0 0 00 1 10 49 28 129 c Oat Bran 47

Fine 3 68 4 05 16 80 46 00 0 1 82 0 44 32 22 77

Oat Flour 45

Example 5

In this example, Fine Oat Bran (333.3 g, 6 7% β-glucan and 15 8% TDF (dwb)) was added to water (1166 7 g, 180°F) containing calcium (100 ppm per gram of starch) and

Termamy 1 (diluted 1 ml in 100 with water, 30 units/g starch) such that the solids content was

20%) and pH of slurry 6 3 The fine oat bran has a mean particle size of 48 μm with 50% of material < 30 μm and 90% < 118 μm. This oat material was added to water that contained starch hydrolyzing enzymes at a constant rate ( l/3^rd every 15 minutes over 45 min period) such that, at no point of time, the viscosity of the slurry was excessively high The slurry was maintained at a temperature of 180 ° F and the hydrolysis continued for another 15 minutes (total time, 1 hour) and the viscosity of resultant slurry was between 6 and 3200 cp The slurry was then cooled to about 131 °F, and Amyloglucosidase (10 units/g starch) was added to the slurry This enzyme treatment was continued for 1 h at 131 °F until the viscosity of the liquid reached -300 cp. This twice-enzyme treated slurry was adjusted to pH 4 with 1 N HCI and then heated to 185 ° F for 20 minutes to inactivate the enzymes. The slurry was then homogenized twice by passing through a Gaulin Homogenizer at 1 ,000/5,000 psi, cooled and the pH adjusted to 6 3 with 1 N NaOH to yield a liquid oat base. Example 6

An orange-cream beverage were prepared from: 800-850 g of water, 20-75 g of oat-base made from Example 1 using 4.62 g of high fructose com syrup, 37 g of orange juice concentrate, 17 g of sugar, 2 g of gum, 2 g of citric acid and colors and flavors. The ingredients were mixed together, homogenized at 500/2,500 psi, bottled, and batch pasteurized by holding 1 minute at 180°F, and cooled immediately to 60°F. The beverages had a pH of 3.8, brix (soluble sugar solids) of 12-14° and viscosity of 30-40 cp. These orange-cream beverages have a good taste, pleasant aroma, no grittiness, and provide 0.75 g of β-glucan per 8 fl.oz serving and qualify for U. S. FDA coronary heart disease health claim.

Example 7

In this example, 3085 grams of skim milk, 2% milk or whole milk (prefer 2% milk) is heated to 190F. 0.8 gram Canalpha όOP dispersed in 100 grams granulated sugar was added to the milk. Medium size oat bran (4.8% b-glucan from ConAgra) was added to the milk/enzyme mixture, and the mixture was vigorously stirred for about 5 min to gelatinize oat starch by heat and partially liquefy the gelatinized oat starch by the enzymatic reaction. The mixture than was heated to boil for 5 min to denature the residual enzymatic activity. The resultant slurry was homogenized immediately through a high speed homogenizer to rupture the cell wall materials in oat bran. After homogenizing, the material was extruded though a masticating juicer equipped with 40 mesh screen three times with slow speed to separate out the insoluble coarse fiber fraction. The final product (filters through 40 mesh) had a pleasant sweet oat taste and creamy smooth texture like chocolate moose. The b-glucan content, pH and viscosity of the product are 0.5-0.9 %, 6.3, and 10,000-35,000cp respectively.

Example 8

In this example, 44.5 pounds of whole grain oat flour (3.2% b-glucan) was mixed into 150 pounds of hot water (150-160F) using a tri-blender. The mixture then was transferred to a steam-jacketed kettle and heat to a temperature of 190-degree F. At this point, 8.17grams of Canalpha 60P dispersed in 300 grams of granulated sugar was added. The mixture was held at

190F for 30 min to gelatinize and partially liquefy oat starch in oat bran. The mixture was transferred to a mix tank and cooled to 100F, and 12.13 pounds of milk solid, 30.13 pounds of sugar, andθ.26 pounds of vitamins/minerals mix, 13.84 pounds ofpeach puree, and0.36pounds of peach flavor, 1.8 pounds of canola oil, and 0.254 pounds of lecithin, were added finally. The final mixture was preheated to 165F in plant heat exchanger and UHT treated (290 for 4-10 seconds) in Sterilab 300 NTIS system. After UHT treatment, the product was homogenized at 160F (2500PSI in the 1 st stage and 500 PSI for the second stage). The product was cooled down to 40-50F and stored in Steritank before aseptic packaging. The final product was packed in 250 ml Tetra-Pak container. The product has a smooth texture and fruity clean oat taste. The b-glucan content of the final product was about 0.3-0.4%). One serving of above product provides 25%)

RDI of typical vitamins andminerals and 0.75- 1.00 grams of b-glucan. The final shelf stable, low acid oat and milk based drink meet FDA health claim.

Other facets of the invention will be clear to the skilled artisan, and need not be set out here. The terms and expression which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expression of excluding any equivalents of the features shown and described or portions thereof, it being recognized that various modifications are possible within the scope of the invention.

Claims

We claim

1

A process for preparing an oat-deπved base compnsmg preparing an oat based slurry having a solids content of between 5 and 45 % oat substrate by weight, said oat substrate containing beta-glucan and oat starches, heatmg the slurry to gelatinize at least a portion of the oat starches, adding an effective amount of at least an enzyme that has substantially no beta- glucanase activity and digesting to the desired endpoint, and inactivating said enzyme to yield the liquid oat base

2 The process of claim 1 , wherein said enzyme is selected from the group consisting of a thermostable alpha-amylase, a heat-labile alpha-amylase, and an amyloglucosidase

3 The process of claim 1, wherein pπor to gelatinization the oat slurry is treated with an enzymaticaUy effective amount of said enzyme

4 The process of claim 1 , further compnsmg removing water to yield an oat-based solid

5 The process of claim 1 , wherein pnor to gelatinization, at least one enzyme selected from the group consisting of a thermostable alpha-amylase, a heat-labile alpha-amylase, and an amyloglucosidase is added to the slurry and the slurry is enzymaticaUy digested at a temperature of from 110 to about 140°F and the resultant slurry had a viscosity between 10 to 2600 cp

6 The process of claim 1 , wherein the aqueous slurry is prepared with milk or skim milk

7 The oat base prepared by the process of claim 1

8 The oat base prepared by the process of claim 2

9 The oat base prepared by the process of claim 3

10 The oat base prepared by the process of claim 4

1 1 The oat base prepared by the process of claim 5

12 The oat base prepared by the process of claim 6