NC-213The U.S. Quality Grains Research Consortium

Marketing and Delivery of Quality Grains and BioProcess Coproducts

Whole Wheat Milling of Hard Red Spring Wheat

Khairunizah Hazila Khalid, Frank Manthey, Jae-Bom Ohm, and Senay SimsekCereal Science Graduate Program

Department of Plant SciencesNorth Dakota State University

NutritiousMacro-

nutrients

1) Whole-wheat flour

Major crop in ND

High protein content

2) Hard red spring wheat

Commercial WWF

3) Whole-wheat milling

Introduction

2kg of sample

Rotor speed 18,000 rpm

4) Centrifugal mill

Affect milling

properties

5) Seed moisture

content

Introduction

Objectives

1. To determine the effect of rotor speed and seed moisture content on quality of whole wheat flour.

2. To evaluate the performance of whole wheat flour on baking quality.

A) Bulk sample of hard red spring wheat.

Grain Quality Value Grain Quality Value

FOSS-Protein (12%mb) 14.9 SKCS-Hardness 95FOSS-Moisture (%) 13.2 SKCS-Weight (g) 35Test Weight (lb/bu) 63.8 SKCS-Moisture (%) 12.31000 kwt (g) 34.4 SKCS-Diameter (mm) 2.6Kernel Distribution Large (%) 61Kernel Distribution Medium (%) 39

Materials

Table 1: Grain quality

FeedingGrindingAir-cooling system

B) Ultra-centrifugal mill with a 250µm screen (Retsch ZM200, Haan, Germany)

Rotor blade

Ring sieve (250um)

Rotor blade

Source: www.retsch.com

Mill Setting Evaluation

Rotor speed, rpm6,000; 9,000; 12,000; 15,000

Seed moisture content, %10%, 12%, 14%, 16%

Feed-rate (vibration)12.6 g/min (30v) 44.5 g/min (40v)

Sample size 200 g

Screen size 250µm

RCBD 3 factorial 3 rep.

Data SAS software

Proc ANOVA LSD

Experimental Design

Exp.1: Milling quality parameters

After milling, these were measured:1. Particle size distribution

vibratory sieve shaker2. Flour temperature

Infra-red thermometer3. Flour moisture content

oven method4. Starch damage

Method 76-30.02 (AACC International)

Particle size distribution(%)• Coarse : > 425µm

• Medium : 425µm > > 150µm

• Fine : < 150µm

Results: Particle size distribution(%)

Rotor speed, rpm

% ground wheat

Coarse>425 μm

Medium425 µm > x > 150 µm

Fine< 150 µm

6,000 0.01 ab 28 a 71 d

9,000 0.02 a 19 b 80 c

12,000 0.00 b 12 c 87 b

15,000 0.01 ab 9 d 90 a

Table 1: Rotor speed – particle size distribution

Values in each column followed by different letters are significantly different (P<0.05)

Results: Particle size distribution(%)

Seed moisture content (%)

% ground wheat

Coarse>425 μm

Medium425 µm > x > 150 µm

Fine< 150 µm

10 0.00 b 18 a 81 b

12 0.01 ab 18 a 81 b

14 0.03 a 16 b 83 a

16 0.01 ab 16 b 83 a

Table 2: Seed moisture content – particle size distribution

Values in each column followed by different letters are significantly different (P<0.05)

Results: Flour QualitiesTable 3: Rotor speed – flour qualities

Values in each column followed by different letters are significantly different (P<0.05)

Rotor speed, rpm

Moisture (%)

Flour Temp. (C)

Starch Damage (14% mb)

6,000 9.0 a 27 a 9.4 b

9,000 9.3 a 27 a 9.6 a

12,000 9.1 a 26 a 8.6 c

15,000 9.0 a 27 a 7.6 d

Results: Flour QualitiesTable 4: Seed moisture content – flour qualities

Seed moisture

content (%)Moisture

(%)Moisture

lossFlour Temp.

(°C)

Starch Damage

(14% mb)

10 8.2 c 1.8 26 c 7.8 d

12 8.6 c 3.4 26 c 8.1 c

14 9.4 b 4.6 27 b 9.3 b

16 10.2 a 5.8 28 a 10.1 a

Values in each column followed by different letters are significantly different (P<0.05)

• Lower starch damage

• Greater fine particle size

Higher rotor speed

• Low starch damage

• Less fine particle size

Low seed moisture content

Summary of Exp.1: Milling quality parameters

Exp.2: Baking performanceEvaluation of flour’s performance:

1. Mixograph - AACC method 54-40.02

2. Baking - AACC method 10-09.01 with modifications, straight dough, 25g loaf.

MixogramMidline peak time (MPT)

Peak Time – indication of well developed gluten in dough system

Results: Mixograph (MPT)Table 5: Rotor speed - midline peak time (MPT)

Rotor speed (rpm)

MPT (min.)

6,000 3.7 b9,000 3.7 b

12,000 3.9 b15,000 4.1 a

Table 6: Seed moisture content - midline peak time (MPT)

Seed moisture content (%)

MPT (min.)

10 4.1 a12 4.0 a14 3.7 b16 3.6 b

Values in each column followed by different letters are significantly different (P<0.05)

Values in each column followed by different letters are significantly different (P<0.05)

Results: Baking QualitiesTable 7: Rotor speed - baking qualities

Rotor speed (rpm)

B. Abs (%)

Dough Handling Prop.

Loaf Vol. (cc)

Grain & Texture

6,000 78.7 a 9.0 b 145.8 b 6.9 ab9,000 78.6 a 9.3 a 154.5 a 6.8 b

12,000 77.9 b 9.5 a 154.0 a 7.1 a15,000 77.9 b 9.3 a 153.3 a 7.0 ab

Values in each column followed by different letters are significantly different (P<0.05)

Grain & texture score: 8.0

Results: Baking QualitiesTable 8: Seed moisture content - baking qualities

Seed moisture

content (%)B. Abs

(%)Dough

Handling Prop.Loaf Vol.

(cc) Grain & Texture

10 78.4 ab 9.4 ab 155.9 a 7.1 a

12 78.5 a 9.4 a 154.3 ab 6.9 a

14 78.3 ab 9.1 b 149.0 b 6.8 a

16 77.9 b 9.2 ab 148.4 b 7.0 a

Values in each column followed by different letters are significantly different (P<0.05)

Grain & texture score: 8.0

Summary of Exp.2: Flour and baking performance

• Better dough handling properties

• Higher loaf volume

Higher rotor speed

• Higher loaf volume

Low seed moisture content

• 12,000 rpm• 12% seed mc

Milling setting

• Fine particle size• Low starch

damage

Whole HRSW flour Quality • Better dough

quality• High loaf

volume

Bread Quality

Conclusion

10% 12% 14% 16%

Seed moisture content

12,000 rpm

10% 12% 14% 16%

Seed moisture content

12,000 rpm

Acknowledgement• We thank personnel at the Hard Red Spring Wheat

Quality and Durum Wheat Quality Laboratory, NDSU, for their assistance and technical support during the study.

NC-213The U.S. Quality Grains Research Consortium

Marketing and Delivery of Quality Grains and BioProcess Coproducts

Questions?

www.wheatquality.com