Development of superior quality bread wheat at KALRO

John N. Ndung’u and Rosemary

Chebwosony,Lucy Kuria, Peter Kimani, Margaret Meso and Joseph Owira

KALRO - NJORO

Grain quality and end-usesGrain quality and end-uses

Why Grain Quality? Why Grain Quality? Quality for : Breeder Farmer Primary processors (Flour millers) Secondary processors (bakers, biscuit, etc) Marketing agencies

Bread wheatFlat breadsSteamed breadleavened breadTandyrMandazi Injera Porridge CakesCookies/

Biscuitsetc

Diverse end uses Diverse end uses

Durum wheat

• Pasta products (macaroni, spaghetti)

• Causcaus• Local bread• Injera

Triticale• Bread • Morning

cereals• Injera• etc

To meet Urban and local needs !!

Wheat quality Wheat quality characterizationcharacterization

Kernel (grain) characteristics

Milling and flour characteristics

Dough/baking (rheological)

End product characterization

Kernel (grain) Kernel (grain) characteristicscharacteristics

Dockage (%) Test weight (Kg hl-1) 1000 grains weight (g) Grain moisture content (%) Hard/vitreous kernels (Vitreousness) Falling number (sec) Protein content (grain or flour) Protein quality

Milling and flour characteristicsMilling and flour characteristicsFlour yield (%) Ash (%)ColorSemolina qualityStarch damageFlour water absorptionFlour protein concentrationFlour chemical composition (%)SDS sedimentation testWet gluten contentGluten index

Dough/baking (rheological) Dough/baking (rheological) parametersparameters

Farinograph

Alveograph

Extensigraph

Mixograph

Farinograph

Mixogram

Alveograph

End product characterizationEnd product characterizationBreadVolumeWeightTexture (internal and external texture)Internal characteristicsBiscuits:DiameterTexturetaste

• Flat bread• Pasta products

• etc

Wheat Quality Improvement in Wheat Quality Improvement in KenyaKenyaObjectives1.Identify main wheat end-uses and grain

quality requirements2.Understand the genetic and G x E factors

influencing wheat quality attributes and end-use quality.

3.Apply quality characterization/screening to:oWheat breeding linesoUsing efficient and high throughput screening

tools.

Interactions on Development of Interactions on Development of superior quality wheat at KALROsuperior quality wheat at KALRO

Breeders: Breeding materials and released varieties◦(Yields, acid soils, dry areas, stem rust)

Pathologists: Lines and varieties being screened for diseases (stem rust, BYDV)

Agronomists: Lines and varieties under agronomic management trials

Entomologist: Lines and varieties being screened for field and storage pests (RWA, Weevils)

Biotechnology (Double haploids and mutants)FarmersMilling companies

Development of superior quality Development of superior quality bread wheat at KALRO bread wheat at KALRO

Breeding activities : F1-F2 Screening for yield and disease resistance : F3-F4 (40 -60 thousand lines) oScreening: Yield, Disease resistance & Quality : F5 o (2 -6 thousand lines) F6 NIR

TestoScreening: Yield, Disease resistance & Quality :F7o (500 – 1000 lines) (All above at Njoro site)

Observation Trials Screening: Yield, Disease resistance &Quality : Milling,

Twt, Protein (100 - 200 lines) Observations (2-3 sites)

Farin/AlveographPYT/AYT: Quality (200-500 lines) (6-7 sites) A.

Amylase NPT trials: Quality (5-10 lines) NIR Baking

Parameters Considered in Breeding Parameters Considered in Breeding for Qualityfor Quality• 1. Milling (Grain)

• Milling extraction rate, duration, milling energy, level of starch damage

• 2. NIR (whole grain and flour)–(Grain Hardness, protein, zeleny, WA and

moisture)• 3.Gluten Strength

– (SDS-Sedimentation, Gluten index, W, P/L)• 4. Enzymatic Activity (Flour)

–(Falling Number)• 5.Dough Rheology (Flour)

–Farinograph, Alveograph,Extensograph and Mixograph)

• 6. Baking Test (Flour)

Quality parameters used by bread wheat breeders Quality parameters used by bread wheat breeders for quality screening in the for quality screening in the United StatesUnited States, , Europe Europe and at and at CIMMYTCIMMYTLocation Early generation

(F2-F5) Advanced generation

(F6 and higher)

United States

Protein, SDS sedimentation, hardness, mixograph

Milling (extraction, ash), Flour protein, Water absorption, Farinograph (time, stability, etc.) Dough characteristics, Loaf volume, Bread characteristics

Europe Protein, SDS sedimentation, Zeleny sedimentation, HMW glutenin subunits

Hagberg falling number, Alveograph (W, P/L), Gluten elastic recovery, Extensometer, Loaf volume, Baking score, Machinability test

CIMMYT Protein, SDS sedimentation, Hardness

Hagberg falling number, Grain and flour protein, High molecular weight glutenin subunits, Flour SDS sedimentation, Mixograph (time, tolerance), Alveograph (W, P/L), Loaf volume; Crumb structure

**Edwards, 1997

Milling TestMilling Test Types:

Buhler, Quadramat, Retsch and Perten mills

During flour milling: o The grain is broken and

endosperm particles gradually reduced in size.

o Large , plump grains show high flour yields

Afterwards:o Separation of the grain into

main parts bran, embryo and endosperm flour/ semolina

o Gradual reduction of endosperm particles to obtain refined flour or semolina (coarse particles)

o ASH Content

Near Infrared Near Infrared Spectroscopy(NIR)Spectroscopy(NIR) NIR Spectroscopy measures

absorption in the Near Infrared.o O-H, N-H, C-H, S-H bonds are

strong NIR absorbers (moisture, protein, fat, fiber, sugars, acids, etc.).

o Hydrogen, Nitrogen Oxygen have no change in dipole moment, hence no NIR absorption.

o NIRS provides both chemical and physical information in flour and grain (non destructive)

Testing samples should cover all the potential variationo Geographical origin, growing

season, etc. when developing a NIR calibration.

Farinograph TestFarinograph TestMeasures: DDT, WA,

Stability and Tolerance

D = Dough development time E = Stability G = Mixing tolerance index (5 min after peak) H = Degree of softening (12 min after peak)

Brabender FarinographBrabender Farinograph

Arrival Time (AT) Peak Time (DT) Stability Time (ST) Departure Time (Dep’t) Absorption Mixing Tolerance Index (MTI)

Mixing characteristics of a flour

Weak (DT and ST values of about one minute, or less) Strong (DTs of 3-5 minutes, and STs of 8-14 minutes) Medium-strong (DTs of 2-4 minutes and STs of 4-7 minutes) Extra strong (DTs of 4-12 minutes and STs of 20-32 minutes) .

Weak/Soft Flour

Strong /Hard Flour

LINK BETWEEN ENDOSPERM TEXTURE, STARCH GRANULE SHAPE& SIZE, PACKED CELL VOLUME AND PROTEIN BODY ULTRASTRUCTURE

SEM

Mixograph TestMixograph TestQuickly analyzes small

quantities of flour for dough strength.

Screen early generation lines for dough strength and WA

WA measured often serves as a measure of absorption in bread baking tests.

Bon Lee, Laboratory Supervisor

MixographMixograph

Alveograph (Chopin) Alveograph (Chopin) TestTest

Measures the extensibility, strength and deformation

Measures: Extensibility, strength, P/L ratio and deformation energy for gluten

AlveographAlveograph

P = tenacity (max. pressure reached blowing the dough piece to rupture)L = extensibility (length of the curve, cm),W = strength of the flour (area of the curve, ergsx103),P/L = configuration ratio of the curve,Ie = P200/P Elasticity (P200 = pressure after 200ml blowing or 4 cm from origin of the curve).

GROUP 1:

RED WEAK WHEAT

LOW PROTEIN

GROUP II:

STRONG STABLE RED WHEAT

MEDIUM PROTEIN

GROUP III:

•STRONG EXTENSIBLE

•RED/WHITE WHEAT

•HIGH PROTEIN

GROUP IV:

SOFT /WHITE WHEAT

LOW PROTEIN

Classes of wheatClasses of wheatUSA: 6 principal classes

Alpha-amylase activity and Falling Number TestAlpha-amylase activity and Falling Number Test• Grain always susceptible to

pre-harvest germination o Carries variable levels of alpha-

amylase activity• In the Falling Number test:

– Alpha amylase activity is indirectly estimated by testing the paste viscosity of whole meal and refined flour

• During the test:o The flour-water slurry is

heated gradually allowing for optimum T for enzymatic hydrolysis.

• Low FN values (60-150 seconds) correspond to high levels of alpha amylase activity.

STANDARDSSTANDARDS National standards

(KEBS)

Factory based standards

AVERAGE STANDARDS OF BREAD AVERAGE STANDARDS OF BREAD WHEATWHEATParameter Basic Grain Quality Standards

Protein Content 12 %

Specific Weight 76 kg/hl

Falling Number >250

Thousand kernel mass >40

Farinograph mixing time 3-6 min (optimum 4 min)

Flour extraction 76 % 

Alveograph P/L ratio 0.5-0.8 (optimum 0.8)

Flour color (as measured by color grader series III)

Cake (-2.5 to 1); white bread flour (1.5-4.5); brown bread(9-14)

Wheat end-usesWheat end-uses Main wheat-based food types

Breads (leavened, flat, steamed) Noodles, Biscuits, Alimentary pasta (spaghetti, etc.) Regional dishes (cous-cous, burghul, porridge).

A wheat variety suitable for one end-use may not be suitable for a different one.

Quality differences result mainly from the grain compositional traits: oGrain hardness oProtein quantity and quality (gluten protein

composition) o Starch pasting properties (amylose / amylopectin

Ratio)

SOFT MEDIUM HARD T. Durum

15

14

13

12

11

10

9

Prot

ein

cont

ent %

Grain hardness

Biscuits,Cakes, Pastry, Puddings

Noodles & Steamed bread

Pasta

Flatbread

Pan breads

Leavened breads

Couscous

Tandyrbread

Main Wheat-based products

Glu

ten

stre

ngth

SOFT MEDIUM HARD T. Durum

15

14

13

12

11

10

9

Prot

ein

cont

ent %

Grain hardness

Biscuits,Cakes, Pastry, Puddings

Noodles & Steamed bread

Pasta

Flatbread

Pan breads

Leavened breads

Couscous

Tandyrbread

Main Wheat-based products

Glu

ten

stre

ngth

Pan BreadPan BreadMechanized pan bread is

important in Kenya urban areas

Main wheat quality requirements: Hard to medium-hard grain High protein content

(>12.5%) Strong and extensible

glutenSoft wheat with weak

gluten not suitable for this baking process

Colour Index

Flat breadsFlat breadsFlat breads (Chapatis) are

very important in rural and urban in Kenya

Main wheat quality requirements:Soft wheat with weak gluten Intermediate protein content

(10-12%)Medium-strong and extensible

gluten

Biscuits and CakesBiscuits and CakesDesirable to avoid the

development of gluten visco-elastic properties.

Achieved by including:High levels of fat and sugar

(30-40% of total formula)Air, water vapor and chemicals

are the main leavening agentsAll acting at the oven stage

Other Types of BreadsOther Types of Breads

Durum wheat productsDurum wheat products Durum wheat-based

products breads are consumed as alimentary pasta globally

Main wheat quality requirements:o Large vitreous grainoHigh yellow pigment

contentoHigh protein content

(>12.5%)oStrong gluteno Low lipoxygenase activity

Biotechnology ApproachBiotechnology Approach Double Haploids Techniques

◦Improvement of protein and Gluten content Mutants (photo)

Increasing Resistant starch and TocopherolIncreasing Zinc and Iron contents Reduced phytic acid content (Photo)

Molecular TechniquesIdentification of Gluten (Glutenins and Gliadins)

MAS helps selecting parental lines with desirable quality genes /alleles in short time

Molecular tools for screening Molecular tools for screening (Inherent quality)(Inherent quality) Bread wheat

(HMW glutenin subunit)

Durum wheatB-LMW glutenins and γ-gliadin

Humans and NutritionHumans and Nutrition

…………Humans and NutritionHumans and NutritionMineral elements are essential components

of wheat metabolism and often accumulate in grain.

Humans require at least 22 of these mineral elements for:Well being which can be supplied by appropriate diet like wheat

Over 60 percent of the world’s 7 billion people are:Iron deficient and over 30 percent are zinc deficient.

…………HUMANS AND NUTRITIONHUMANS AND NUTRITIONIn addition, protein, calcium and magnesium deficiencies are common in

developed and developing countries including Kenya.

2B people are nutritionally hungry in worldResistant starch (RS) is known to have healthy benefits for human

Should be encouraged to form part of daily diet

Presence of antinutrients eg phytic acid in wheat

Micronutrient malnutrition (Hidden Micronutrient malnutrition (Hidden hunger)hunger)

Source: World Health Organization

Solution Challenge1 Micronutrient supplements for children (Fe&zinc) Malnutrition2 The Doha development agenda Trade3 Micronutrient fortification (iron and salt

iodization)Malnutrition

4 Expanded immunization coverage for children Diseases5 Biofortification Malnutrition6 Deworming, other nutrition programs in school Malnutrition7 Lowering the price of schooling Education8 Increase and improve girl’s schooling Women9 Community-based nutrition promotion Malnutrition10 Provide support for women’s reproductive role Women

Reference: http://www.copenhagenconsensus.com

Methodologies for Nutrition Methodologies for Nutrition analysisanalysis

Atomic Absorption spectrophotometry for Minerals analysis

Phytic acid AssayMegazyme kit for

Resistant starch analysis

NIR/Kjedhal apparatus for protein analysis

Value additionUse of induced

mutation

Achievements/ ChallengesAchievements/ ChallengesKALRO Njoro cereal chemistry lab has

contributed to the release of170 commercial high quality varieties since 1920s

Recently contributed to release of 10 varieties

Screened 20 commercial varieties for nutritional profile

Trained Millers on wheat grading and qualityOther crops quality analysisAchievements/awardsEquipments

ConclusionsConclusions• To succeed in quality improvement it is

important to:Identify main end uses in targeted areasDetermine main grain traits affecting

processing qualityUse efficient, high throughput quality

screening toolsDetermine end-product quality and shelf life

attributesUnderstand genetic control of quality traits Determine G x E factors influencing end-use

quality

Thank you…

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Selection of KM14 M2 mutantsSelection of KM14 M2 mutants

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