John Taylor University of Pretoria, South Africa

Traditional African Food TechnologiesSolutions to 21st Century Africa’s Challenges

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Gauteng – South Africa

NASA Satellite View June 2002

Image specially taken for for Second UN World Summiton Sustainable DevelopmentHeld in Johannesburghttps://www.jpl.nasa.gov/spaceimages

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CLIMATE CHANGEEffects of Drought on Maize in Western Kenya

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Adomi Bridge, Ghana

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Wheat imports

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GHANA – Wheat imports and Urban population trends(FAOStat data)

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NIGERIA – Wheat imports/production and Urban population trends1988-2013 (FAOStat Data)

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Maize production

UrbanPopulation

Wheat production

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SOUTH AFRICA – Cereal Production and Import and Urban Population trends (FAOStat data)

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THE HYPOTHESES

1. Sub-Saharan Africa can only achieve Food Security through greatly expanded cultivation and utilization of staple Food Crops that are well-adapted to increasingly Hot and Arid climatic conditions

2. There is an Urgent need to develop Technologies to Economically Process these “Climate Smart Food Crops” into Food Products that meet the Nutritional and Lifestyle needs

of Africa’s increasingly young and urban population

3. Much can be learnt from Africa’s Traditional food and beverage Processing Technologies and Products

- What is called Indigenous Knowledge (IK)

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KenyaGovernment

Response2018

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“Okafor (Nigerian Bakery Association head) lamented that six years on, the initiative has clearly failed

He said: "The fund was to be used to for the development of cassava bread which includes training, equipping of 5,000 bakers,

As we speak, only 1,584 bakers have been trained, only 151 bakeries have been partially equipped in a very unacceptable circumstances”

NIGERIA ABANDONED ITS

CASSAVA-WHEAT BREAD DEVELOPMENT PROGRAMME IN 2018

(From AllAfrica.com 26 April 2018)

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30% Cassava-Wheat Blend Bread

FAO Cassava Food Processing Workshop in Ghana - 2017

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WHY ARE THESE INITIATIVES NOT SUCCESSFUL?

Model for Glutenin Network ElasticityLétang C. et al. 1999. J Food Eng 41:121

Startof mixing

Optimummixing

“Loops” of glutenin polymers - Glutenin Relaxed

“Trains” of gluteninpolymers H bonded together- Gluten Stretched

Loop

Wilde P. 2012 In: Breadmaking:Improving Quality. S.P. Cauvain (Ed.)

During fermentationThe Gas bubbles in Dough Expand

The Lamellae (film)between the Bubbles Comes thinner

Elastic response of GlutenRestores film

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• In Wheat bread dough with gas bubble expansion at Advanced stages of fermentation and Early stages of baking - Only Liquid Lamellae separate the Bubbles

- Bubbles are unstable• As there is no Gluten in Non-wheat doughs Lamellae between the bubbles is

essentially a liquid - Even during Early stages of fermentationHence, non-wheat doughs foams are very unstable

Gan Z et al. 1995.J Cereal Sci 21:215.

DOUGH LIQUID FILM HYPOTHESIS

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In fact Africa has its own Traditional Non-wheat Breads

Kisra Injera

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WATER → TEFF or SORGHUMor FINGER MILLET

FLOUR(or combination)

↓DOUGH MAKING(Knead by hand)

↓STARTER CULTURE

(Ersho) (from previous fermentation,

5% on flour basis)

→MIXED YEAST

AND BACTERIA (Sourdough-type )FERMENTATION

↓DIVIDE DOUGH

(3:1)→ COOK PART

OF DOUGH (Absit)(Starch Gelatinization)

↓↓ COOL

(to 45oC)↓

ADD WATER (To make batter)

← ADD BACK TO DOUGH

↓FERMENTATION

(Sourdough type)(2-3 hours)

↓POUR BATTER ONTO

BAKING GRIDDLE(50 cm. diam clay griddle (Metad)

→ BAKE(Close lid,

Bake for 2 min)

Injera making Process Highlighting Traditional

Technologies Steps

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Camagwini Michelle MakabelaBSc (Hons) Food Science University of Pretoria 2018

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SOURDOUGH FERMENTATION

IS ATTRIBUTED TO HAVE MANY POSITIVE EFFECTS

ON BREAD QUALITY

Acidification - Modifying bread structure-forming polymers Reduction – Breaking of protein S-S bondsAmylase and protease activities -Partial breakdown of structure-forming polymers Exopolysaccharide production -Acting as hydrocolloids

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SOURDOUGH FERMENTION OF SORGHUM + POTATO STARCH BREAD

Bread made with HydrocolloidBread made with Hydrocolloid + Sorghum Flour first Sourdough fermented with L. plantarum

Schober et al. 2007. J Agric Food Chem

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CLSM of crumb of sorghum + potato starch bread Made with b) Chemical acidificationc) Sourdough

“Results suggest that a Strong Starch Gel, without interference of aggregated protein, is desirable for Non-wheat bread”

SEC of Sorghum SourdoughDough Liquid and Protein Extracted with SDSa) Before fermentation, b) After fermentation

Schober et al. propose that positive effect of sourdough fermentation on non-wheat bread crumb structure is actually due to breakdown the storage proteins

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Effect of SourdoughFermentation on Sorghum

and FonioMixolab dough profile

Edema, M.O. et al. 2013.Starch/Stärke

Sorghum FermWheat (standard)Sorghum Unferm

Black Fonio 2 FermBlack Fonio 1 FermBlack Fonio 2 UnfermBlack Fonio 1 Unferm

White Fonio 1 FermWhite Fonio 2 FermWhite Fonio 1 UnfermWhite Fonio 2 Unferm

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b

b

c d

e f

10µm 10µm

10µm 10µm

10µm 10µm 10µm 10µm

Effect of SourdoughFermentation on Fonio Starch Granules

Unfermented Fermented

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Maize flour dough Stress-Relaxation curves

Regular doughAcidifedL. plantarum sourdoughMultiple strains sourdough

Good Evidence to support Sourdough Starch Modification by Sourdough

Dough treatment

Gelatinisation onset temp.

(oC)

Gelatinisation peak temp.

(oC)

Gelatinisation endset temp.

(oC)

Enthalpy(Delta H)

(J/g)

Regular dough

74.43a 81.09bc 88.68a 0.38a

Acidified dough

73.83a 82.05c 89.84a 0.49a

L. plantarumsourdough

72.87a 79.81b 89.84a 1.06b

Multiple strains starter culture

71.39a 77.28a 88.13a 1.13b

Thermal properties of the maize doughs

Falade AT et al. 2014. J Cereal Sci.

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Effects of Acidification and SourdoughFermentation onMaize dough and Bread Structure

Falade AT et al. 2014J Cereal Sci.

Dough

Bread

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InjeraIs not just

a“Flat”Bread

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The Custard (Batter) Breadmaking ProcessInclusion of Cooked (Pre-gelatinized) Flour – As a Hydrocolloid

1 January 1988The Nigerian Government

Banned the Importation of Wheat

The Nigerian Federal Institute of Industrial Research

Developed 70% Maize/Sorghum/Millet-

30% Cassava Batter Bread

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YEAST FERMENTED DOUGHS

Wheat Sorghum

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D.S Murty and K.A. Kumar of ICRISATTraditional uses for Sorghum and Millets

Roti“Sometimes a small quantity of Four Cooked in Water is added to the dry flour during dough preparation. The Gelatinization of part of the flour improves the Elasticity and

Cohesiveness of the Dough and produces a roti with improved quality”

1995

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Raw Maize flour+Pre-gelatinized maize flour

1 6 sheeting passes

Raw Maize flour only

5 40 sheeting passes

Making non-wheat flourDoughs using sheeting

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SORGHUM DOUGH SHEETING AND INCLUSION OF PRE-GELATINIZED FLOUR

a b c d

a) No pre-gelatinized flour, (b) 10% pre-gelatinized flour, c) 20% pre-gelatinized flour, (d) 30% pre-gelatinized flour

Magabane et al. (unpublished)

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Number of Sheeting passes1 2 3 4 5 7

5 mm 5 mm 5 mm 5 mm 5 mm 5 mm

What happens to the pre-gelatinized flour when the dough is sheeted

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Maize Pan breads made with Pre-gelatinised flour + either Gluten or Zein (Maize prolamin protein) or Sourdough or Zein + Sourdough

Strands of zein

Maize flour + pre-gelatinised maize flour +Sourdough

Maize flour + pre-Gelatinised maize flour+Sourdough + Zein

“Papery”Gas cellWalls

Linear Gas cell Walls

Proof height 18.5BLoaf height 39.3bc

Proof height 26.5CLoaf height 42.5bc

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Wheat flour Chapattis Kenya and Mauritius

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CONCLUDING REMARKS

• Not possible to produce a Consumer-acceptable Conventional Pan-type Bread using CSFC flours retailing at “R10” a loaf

• For sub-Saharan Africa to become Food Secure we must utilise its CSFCsto produce our staple foods and beverages

• To succeed - We can learn much from Indigenous Knowledge of CSFC foods and their technologies – If it is not lost first

• Traditional African Foods and Beverages and their Technologies should be a Food Science and Technology degree module in Africa’s universities

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David Carroll1954 - 2019

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David and all the other students It has been

My great privilege to teach

You Have Been My Inspiration

David Carroll1954 - 2019

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