METHODS FOR PREPARING OAT BRAN ENRICHED IN BETA-GLUCAN AND OAT PRODUCTS PREPARED THEREFROM

• US 20090078802A1
• Filed: 09/21/2007
• Published: 03/26/2009
• Est. Priority Date: 09/21/2007
• Status: Active Grant

• Current Assignee: General Mills Incorporated
• Original Assignee: General Mills IP Holdings II, LLC (General Mills Incorporated)
• Inventors: Dietsch, Michael, Hellweg, JH, McKeehen, John
• Granted Patent: US 7,976,888 B2
• Time in Patent Office: Days
• US Class Current: 241/8
• CPC Class Codes: A21D 13/02 Products made from whole meal; Products containing bran or rough-ground grain
• CPC Class Codes: A21D 2/18 Carbohydrates
• CPC Class Codes: A23L 7/115 Cereal fibre products, e.g. bran, husk
• CPC Class Codes: A23L 7/17 by extrusion

Abstract

Dry milling methods for preparing oat products enriched in the content of β-glucan and methods for preparing foodstuffs incorporating such an enriched oat product especially ready-to-eat cereals are provided. Heat conditioned dehulled oats are dry milled to form a coarse whole non defatted oat flour and then, without a preceding removal of fat, dry fractionated into coarser bran and finer oat flour fractions at multiple stages. The coarse oat flour is first dry classified to separate or form a coarser fraction oat bran containing more concentrated β-glucan and a finer oat flour or starch containing or endosperm containing fraction. The oat bran is fractionated into a coarse and fine oat bran sub-streams. The oat bran sub-streams are each is subjected to second roller milling step and then bolted. The second bolting of oat bran is then subjected to a third round of milling and classification to form a high β-glucan content (>7-9%) oat bran and a low β-glucan content (3%) oat flour. The methods are low cost and commercially practical. Preferably, the high β-glucan content oat bran and oat flour fractions can have a syringic acid to ferulic acid ratio of at least 2.5:1 indicating improved flavor. Preferably, the oat bran and oat flour have a Farinograph value of 5 to 20 minutes indicated partial gelatinization. The oat bran and oat flours can be used to prepare foodstuffs such as ready-to-eat cereals.

Claims

1. A method to form an oat bran fraction and oat flour fraction, comprising the steps of:

bolting (20) coarse whole heat conditioned grain oat flour (19) having a native β

-glucan content to form a first pass coarse oat bran 21A having a particle size greater than about 1030 μ

m (being retained on a US #18 screen), a 1^st pass fine oat bran 21B having a particle size of less than 1030 μ

m (passing through a US #18 screen) but greater than about 520 μ

m (being retained on a US #34 screen) and a first pass low bran oat flour (22) having a particle size of less than about 420 μ

m (through a US Standard Size #40 screen);

flaking (24) each of the first pass oat bran sub-streams 21A and 21B to form flaked oat brans (25 and 25B);

bolting (26) the flaked first pass oat bran to form a first coarser major second pass β

-glucan rich oat bran fraction (28) having a particle of greater than 520 μ

m (passing through a US #34 screen) and a second finer minor second pass low bran oat flour (27) having a particle size of less than 520-μ

m (passing through a US #34 screen);

hammer milling (30) the second pass β

-glucan rich oat bran fraction (28) to form a milled oat bran (31); and

,

bolting (32) the milled oat bran (31) to folds a first coarser major third pass β

-glucan rich oat bran fraction (50) having a particle of greater than 300 μ

m and a second finer minor third pass low bran oat flour (33) having a particle size of less than 300 μ

m.

2. The method of claim 1 wherein the third pass β

-glucan oat bran fraction has a β

-glucan concentration at least 150% of the native level.

3. The method of claim 2 additionally comprising the step of combining at least a portion of the first pass low bran oat flour and the second pass low bran oat flour and the third pass low bran oat flour to form a low bran oat flour having a β

-glucan, glucan content of no more than 50% of the native level.

4. The method of claim 2 wherein the coarse whole heat conditioned grain oat flour (19) having a native β

-glucan content ranging from about 3-4% and wherein the third pass β

-glucan rich oat bran has a β

-glucan content of between 7 and 9%.

5. The method of claim 4 wherein the flaking step 24 is practiced employing a milling counter rotating double roll stand.

6. The method of claim 2 additionally comprising the steps of:

exposing oat groats having a native level of peroxidase activity to steam for sufficient time to deactivate the peroxidase enzyme activity to provide steamed oat groats having a moisture content of about 16 to 25%; and

dry heating the steamed oat groats at about 85 to 110°

C. (185 to 230°

F.) for about 70 to 110 minutes to provide steamed and toasted oat groats having a moisture content of about 9 to 14%;

milling the steamed and toasted oat groats to form a coarse oat flour.

8. The method of claim 6 wherein the steamed and toasted oat groats have a Farinograph value of about 5 to 20 minutes.

9. The method of claim 8 wherein the steamed and toasted oat groats have a ratio of the HPLC syringic acid peak to ferulic acid peak ranging from about >

2.5.

11. The method of claim 4 additionally comprising the step of:

combining oat flour (19) with the high β

-glucan content oat bran (50) in a weight ratio ranging from about 100;

1 to about 1;

10 to form a high β

-glucan oat flour (80).

12. The method of claim 11 additionally comprising the steps of:

combining the high β

-glucan oat flour (80) with water, salt(s) and R-T-E cereal ingredients to form a oat flour cereal blend;

cooking (90) the oat flour cereal blend to form a cooked high β

-glucan oat cooked cereal dough (92); and

forming (100) the cooked cereal dough 92 into a finished whole oat R-T-E cereal (110).

13. The method of claim 12 wherein forming step includes:

puffing quantities of the cooked cereal dough 92 to form puffed whole oat puffed pieces (110).

14. The method of claim of claim 1 additionally comprising the step of:

collecting the first pass low bran oat flour.

15. The method of claim 14 additionally comprising the step of:

collecting the second pass low bran oat flour.

16. The method of claim 1 comprising the steps of:

collecting at least a portion of low bran oat flour;

cooking the low bran oat flour to form a cooked low bran oat cereal dough; and

,

forming the cooked low bran oat cereal dough into finished RTE cereal pieces.

17. The method of claim 12 wherein forming step (100) additionally comprises the sub steps of:

flaking the pellets to form wet oat flakes having a moisture content of about 12 to 18%; and

,

toasting the flakes to form toasted oat flakes.

18. The method of claim 12 wherein the cooking (90) is continued for about 0.5 to eight minutes in a single or twin screw cooker extruder to form a cooked cereal dough having a moisture content of about 12 to 35%.

19. The method of claim 17 wherein the cooking (90) is continued for about 0.5 to eight minutes in a single or twin screw cooker extruder to form a cooked cereal dough having a moisture content of about 12 to 35%.

20. The method of claim 18 wherein the cooking (90) and forming step are practiced in a twin screw extruder and comprises the sub step of directly expanding the cooked cereal dough to form puffed R-T-E cereal pieces.

21. The method of claim 20 wherein the puffed pieces are ring shaped.

22. The method of claim 21 wherein step F additionally comprises the sub step of drying the puffed piece to a moisture content of about 2 to 6%.

23. The method of claim 13 wherein in step E the cooking is continued for about 30 to 70 minutes at 93 to 110°

C. to form a cooked cereal dough having a moisture content of about 12 to 35%.

24. The method of claim 23 wherein step F comprises gun puffing the cereal pellet to form puffed whole oat puffed R-T-E cereal pieces.

25. The method of claim 24 wherein step F additionally comprises the sub step of toasting the puffed whole oat puffed R-T-E cereal pieces.

10. The method of claim 7

wherein the dry heating step comprises the sub steps of:

1) venting the steamed oat groats having a moisture content of 16% to 25% to form steamed and vented oat groats having a moisture content of 15 to 20%; and

,

2) dry heating the steamed and vented oat groats at about 85 to 110°

C. (185 to 230°

F.) for about 70 to 110 minutes to provide conditioned oat groats having a moisture content of about 9 to 14%; and

wherein in the steam exposing step, the steam has a pressure of about 5 to 15 psig (100 to 200 KPa).