John Taylor

Institute for Food, Nutrition and Well-being and

Department of Food Science University of Pretoria John.taylor@up.ac.za

TRADITIONAL

AFRICAN

CEREAL FOODS

AND BEVERAGES

HOW THEY CAN HELP US DEVELOP

BETTER GLUTEN-FREE PRODUCTS

Where are all these new apartment buildings – China?

WHY GLUTEN-FREE FOOD AND BEVERAGE PRODUCTS?

No In fact Addis Ababa – Ethiopia

Until the “Age of Discovery” starting in the 15th Century Most People in the World

did not know Wheat and Barley

People in the Americas, Asia and Africa Developed Sophisticated Technologies

to Optimise the Processing of their Local Grains

Phylogenetic relationship between the cereal species

www.maizegenetics.net

Phylogenetic relationship between the cereal species

www.maizegenetics.net

`

`

Beers and Non-alcoholic Cereal Beverages

African Soured Non-alcoholic Cereal Beverages

Uji Motoho Mageu Kenya Lesotho South Africa

Bacteria from a traditional African soured beverage (strain of Lactobacillus plantarum)

Lactic acid bacteria on starch granules in sorghum fermentation

Traditional Opaque-type Sorghum Beer – Southern Africa

Sorghum Lager Beer Brewery next to Lake Victoria - Uganda

50

60

70

80

90

100

110

0 50 100 150 200 250

Brewing time (min)

Tem

pera

ture

(o

C)

MASH IN

COOKING

MASHING

Fungal alpha-amylase

Simplified General Process

for Brewing Sorghum Lager/Stout using Raw Sorghum, Sorghum Malt and

Commercial Enzymes

Sorghum Malt or Thermostable Alpha-amylase

Proteases Cellulases

+

Raw Sorghum

Traditional Cloudy-type Pito (Dolo) Beer

- Ghana (Burkina Faso)

Dolo/Pito Beer Making in Burkina Faso and Ghana

Sorghum floor malting for Pito Beer- Ghana

Mashing

Mashing

Adding Grewia bark (contains a hydrocolloid) to sorghum malt mash

Starchy adjunct cooking

Adding the starchy adjunct to the mash cooker

Starchy adjunct Cooking and Mashing processes

After cooking – The adjunct it is returned back to the mash vessel (foreground)

Mashing is then carried out overnight

Flocculation of wort insoluble solids

Wort clarification

Sorghum malt

Warm Water

What Were The Ladies Doing In the Mashing Process?

Step 1: Add sorghum malt to warm water with stirring

Step 2: Add Hydrocolloid Allow starchy solids to settle out

Enzyme extract Starchy Solids

` Step 3: Remove starchy solids

Enzyme extract Starchy Solids

` Step 4: Cook starchy solids to gelatinise the starch

COOK

Enzyme Extract

Cooked Starchy Solids

Step 5: Allow to cool somewhat Add cooked starchy solids back to enzyme extract

Step 6: Mash

Malt amylases hydrolyse cooked starch into sugars

“Recently, a decantation mashing procedure was devised to convert sorghum malt more efficiently”

1. The mash is carried out at 45oC for 30 min

2. The active enzymic wort (amylase enzyme rich solution) is

decanted

3. The starchy-grist residue is heated to 80oC or 100oC to gelatinize the starch

4. The mash is then cooled and the decanted enzymic wort is re-added to achieve a conversion (starch hydrolysis) temperature of 65oC”

From: G.H. Palmer et al. 1989. MIRCEN J Appl. Micro. Biotech 5: 265

Effect of Different Mashing Conditions with Sorghum Malt

Taylor, JRN.1992. J. Amer. Soc. Brew. Chem. 50:13

(from β-amylase) (from α-amylase)

Decoction

Breads and Baked Goods

LACTIC ACID

FERMENTATION

Sourdough Technology

Traditional in Africa

For Making Breads with

Non-wheat Cereals

- Sorghum, Maize, Millets,

Rice, Teff

Traditional KISRA

flatbread from Sorghum

- Sudan

OLD? DOUGH-MAKING TECHNOLOGY

INJERA flatbread - Ethiopia

INJERA FLOWCHART

KEY INJERA TECHNOLOGIES

• Mixed yeast LAB sourdough fermentation • Pre-gelatinise part of the dough

Yetneberk S. et al. Cereal Chem. 2004.

Sourdough Fermentation Increases Maize Bread Loaf Volume

- Much larger gas cells and open crumb structure

Falade A T et al. J. Cereal Sci. 2014.

Effect of Sourdough fermentation on Mixolab dough profile

Edema, M.O. et al. 2013.

Starch/Stärke

Sorghum ferm Wheat-(standard) Sorghum unferm B Fonio 2 ferm B Fonio 1 ferm B Fonio 2 unferm B Fonio 1 unferm W Fonio 1 ferm W Fonio 2 ferm W Fonio 1 unferm W Fonio 2 unferm

Sorghum and Fonio Compared to Wheat

Dough

Bread

Sourdough fermentation produces a more cohesive maize dough - Larger more uniform gas bubbles/cells

in the dough and bread

Straight dough With yeast

Chemically acidified dough With yeast

L. plantarum fermented dough With yeast

Sourdough fermented dough With yeast

L. plantarum fermented dough No yeast

Sourdough fermented dough No yeast

Falade A T et al. J. Cereal Sci. 2014.

1

101

102

103

104

105

106

Pa

G'

100

101

10-3

10-2

10-1

100

101

102

%

Strain

CSD

Anton Paar GmbH

spontaneously fermented maize dough without yeast 1c 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

l.plantarum fermented maize dough without yeast1b 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

myny2b 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

chny3a 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

d

c b

a

102

103

104

105

G''

100

101

10-3

10-2

10-1

100

101

102

%

Strain

CSD

Anton Paar GmbH

spontaneously fermented maize dough without yeast 1c 1

PP25-SN25508; [d=2 mm]

G'' Loss Modulus

l.plantarum fermented maize dough without yeast1b 1

PP25-SN25508; [d=2 mm]

G'' Loss Modulus

myny2b 1

PP25-SN25508; [d=2 mm]

G'' Loss Modulus

chny3a 1

PP25-SN25508; [d=2 mm]

G'' Loss Modulusd

b

a

c

100

101

102

103

104

Pa

10-3

10-2

10-1

100

101

102

%

Strain

CSD

Anton Paar GmbH

spontaneously fermented maize dough without yeast 1c 1

PP25-SN25508; [d=2 mm]

Shear Stress

l.plantarum fermented maize dough without yeast1b 1

PP25-SN25508; [d=2 mm]

Shear Stress

myny2b 1

PP25-SN25508; [d=2 mm]

Shear Stress

chny3a 1

PP25-SN25508; [d=2 mm]

Shear Stress

b a

d c

B

A

Elastic modulus Loss modulus Shear stress

103

104

105

106

Pa

G'

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160°C

Temperature T

G', G''

Anton Paar GmbH

msscny4a 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

lpny1 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

myny2b 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

chny3b 1

PP25-SN25508; [d=2 mm]

G' Storage Modulus

a b

c d

102

103

104

105

Pa·s

| *|

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160°C

Temperature T

G', G''

Anton Paar GmbH

msscny4a 1

PP25-SN25508; [d=2 mm]

| *| Complex Viscosity

lpny1 1

PP25-SN25508; [d=2 mm]

| *| Complex Viscosity

myny2b 1

PP25-SN25508; [d=2 mm]

| *| Complex Viscosity

chny3b 1

PP25-SN25508; [d=2 mm]

| *| Complex Viscosity

a b

c d

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65

0.7

0.75

0.8

tan( )

20 30 40 50 60 70 80 90 100 110 120 130 140 150 160°C

Temperature T

G', G''

Anton Paar GmbH

msscny4a 1

PP25-SN25508; [d=2 mm]

tan( ) Damping Factor

lpny1 1

PP25-SN25508; [d=2 mm]

tan( ) Damping Factor

myny2b 1

PP25-SN25508; [d=2 mm]

tan( ) Damping Factor

chny3b 1

PP25-SN25508; [d=2 mm]

tan( ) Damping Factora

d c

a

b

b

c

a

d

c

b

a

d

c a

c d

a c b

d

b

d c b

a

b

d

Tan delta Complex viscosity Elastic modulus

a: Maize dough. b: Chemically acidified maize dough. c: L. plantarum fermented maize dough. d: Multiple strains starter culture fermented maize dough

Effects of L. plantarum fermentation or multiple strains starter culture fermentation - Rrheological properties of maize dough A: strain sweep analysis parameters B. Temperature sweep analysis parameters

Falade AT et al. J Cereal Sci. 2014

b

b

c d

e f

10µm 10µm

10µm 10µm

10µm 10µm 10µm 10µm

Effect of Sourdough Fermentation on

Fonio Starch Granules

Unfermented Fermented

Edema MO et al. 2013 Starch/Staerke

MODIFY MAIZE ZEIN WITH LACTIC/ACETIC ACID

A = Unmodified Zein + Starch flour after mixing

B = Modified Zein + Starch flour after mixing; C = Dough properties

D = Alveograph dough bubble of Modified Zein + Starch dough

Sly AC et al. 2014. J Cereal Sci

Maize flour

Maize flour

+Zein - only

Wheat

flour

FUTURE OF GLUTEN–FREE

PRODUCTS IN AFRICA

Combine Traditional and Modern Technologies

Beers and non-alcoholic cereal beverages • Reduce gelatinization temperature of tropical cereal starches

• Optimise tropical cereal malt beta-amylase activity

• Improve tropical cereal protein and cell wall digestibility

• Lactic acid fermentation

Breads and Baked Goods • Application of flour improvers – Enzymes etc

• Use of Hydrocolloids and Gums

• Develop novel dough-making technologies – To handle batters

• Co-proteins – Legume proteins + Cereal proteins

• Sourdough fermentation

See – Forthcoming Special Issue of the Journal of Cereal Science

“Functionality of Cereal Based Non-gluten Dough Systems” Edited by John Taylor and Cristina Rossell

DEDICATION

Dr Mojisola Edema

Federal University of Technology, Nigeria