BIOFORTIFICATION OF CEREAL GRAINS
FOR IMPROVED NUTRITION IN AFRICA: STRATEGIES, BENEFITS AND CHALLENGES
John R N Taylor, Janet Taylor, Johanita Kruger
Institute for Food, Nutrition and Well-being and
Department of Food Science University of Pretoria
South Africa
and Laura S Da Silva Department of Biotechnology and Food Technology
Tshwane University of Technology South Africa
IMPACT INADEQUATE FOOD AVAILABILITY AND LACK OF DIETARY DIVERSITY
IN RURAL BURKINA FASO Survey >100 Two-Five year olds • 97% of diet was cereals • 70% of children were energy deficient • 10-15% were protein deficient • Vitamin A intake a fraction of requirement • Iron intake 1/3 of RDA
From: Taylor, Janet, Taylor, JRN, Kini, F. 2012. Cereal Foods World 57: 165
Cooking Maize to make Tô – Burkina Faso
Refining the Maize Meal For Tô Making
REFINED WESTERN CEREAL FOOD
FROM THE HEALTH FOODS SECTION IN THE SUPERMARKET
MICRONUTRIENT FORTIFICATION
Harvesting Sorghum – Homa Bay, Lake Victoria, Kenya Photo – courtesy of Nokuthula Vilakati (PhD student University of Pretoria)
SUBSISTENCE FARMING
BIOFORTIFICATION
Aims to increase Density and Bioavailability
of key limiting nutrients, particularly micronutrients,
in staple food crops such as grains
• Primarily by Conventional Breeding and Genetic Modification
• With Biofortification the recurring costs can be minimised
Golden Rice 2
Photo: International Rice Research Institute via Wikimedia
Commons
MAJOR CEREAL BIOFORTIFICATION PROJECTS
IN AFRICA
GRAIN PROJECT NAME
INSTITUTION
TRAITS AND
LEVELS ACHIEVED
PROGRESS TO
2013
Maize Quality Protein
Maize
CIMMYT
Lysine: up to 100% Varieties widely
disseminated and
used for up to 10
years
Maize Vitamin A Maize
HarvestPlus
Vitamin A
15 mg β-carotene
equiv./kg
Varieties released
Pearl millet ICRISAT Iron: 67-73 mg/kg
Zinc: 41-56 mg/kg
Varieties released
Sorghum Africa Biofortified
Sorghum Project
Africa Harvest
Biotechnology
Foundation
International
Lysine: 75-97% All enhanced traits
demonstrated
but not all together
in the same line
Controlled field trials
commenced
Protein Digestibility
Raw: 61-83%
Cooked: 43-59%
Mineral Bioavailability
Iron: 6-20%
Zinc: 25-39%
Vitamin A
Up to 14 mg β-
carotene equiv./kg
AFRICA BIOFORTIFIED SORGHUM (ABS) PROJECT Using Recombinant DNA Technology (Genetic Modification) to: • Increase levels of essential amino acids –Lysine • Improve Protein Digestibility (Bioavailability) • Improve Iron and Zinc Bioavailability
• Dramatically increase Provitamin A content - Focus on sorghum – Staple of 500 million most food insecure people
IMPROVEMENT IN SORGHUM PROTEIN QUALITY (Lysine Content and Protein Digestibility)
Using RNAi Technology : • Supress synthesis of certain of the lysine-deficient kafirin storage proteins
• Supress synthesis of certain of the kafirin types that cross-link (e.g. γ-kafirin)
• Supress synthesis of enzyme that breaks down lysine (LKR)
Express transgene coding for a high lysine protein (HT12)
Da Silva, LS, et al. 2011. J Agric Food Chem 59:9265
Effect on Protein Bodies
a) TG high digestible line
b) Null Control
c) Non-GM high
digestibility line
Sorghum Protein Bodies
Synthesised in the
endoplasmic reticulum
M
N1 T1 N2 T2
Non-reducing conditions
N1 T1 N2 T2
Reducing conditions
SDS-PAGE of kafirin proteins from ABS sorghum lines compared
to the Null controls
1) Molecular markers, 2) NC1, 3) TG1, 4) NC2, 5) TG2,
Da Silva LS, Taylor J,
Taylor, JRN 2011
J Agric Food Chem 59:9265
O
D
M
SORGHUM GRAIN
FUNCTIONAL QUALITY
Sections through ABS
Sorghum Grains
and their Null controls
Top – Unimproved TG lines
Middle – Their null controls
Bottom – TG lines crossed
into improved varieties
Da Silva LS et al. 2011.
J. Cereal Sci. 54:160
BUT – PEOPLE DO NOT EAT GRAIN
THEY EAT FOOD PRODUCTS
<- Real Injera – 50 cm diam ->
“Mini Me” Injera 9 cm diam
UGALI
(Thick
porridge)
TÔ
(Alkali
cooked
porridge)
UJI
(Fermented
porridge)
INJERA
(Ferm-
ented
flatbread)
ROTI
(Flatbread)
COUSCOUS
(Steamed
Agglomer-
ated flour)
COOKIES
Amino Acid
Score
(based on
lysine)
Null
Controls 0.34 0.32 0.34 0.39 0.30 0.33 0.32
ABS
Sorghum 0.48 0.48 0.50 0.49 0.48 0.50 0.45
In vitro
Protein
Digestibility
(%)
Null
Controls 44.1 57.6 57.7 54.3 49.7 31.7 35.3
ABS
Sorghum 61.7 72.2 73.6 68.7 64.5 45.7 53.7
Amino Acid Score and In vitro Protein Digestibility
of Food Products made from ABS Sorghum
Taylor J and Taylor JRN 2011. J Agric Food Chem 59:2386
Sorghum Control
ABS Sorghum
Wheat
Maize
Rice
Pearl Millet
Protein (g/100 g flour)
10.6 12.8 14.5 10.5 9.6 14.5
In vitro Protein Digestibility of Porridge (%)
60 74 86
85
84 72
75
Lysine (mg/g protein)
18
32 27 29 39 33
Amino Acid Score (based on lysine)
0.34 0.62 0.52 0.55 0.74 0.64
PDCAAS 0.21 0.45 0.44 0.47 0.62 0.53
0.48
Henley, EC, Taylor, JRN, Obukosia, SD. 2010.
In: Advances in Food and Nutrition Research, Academic Press,
Vol. 60 pp. 21-52.
PROTEIN CONTENT, IN VITRO PROTEIN DIGESTIBILITY,
LYSINE CONTENT, AMINO ACID SCORE AND PDCAAS OF ABS
IMPROVEMENT IN MINERAL BIOAVAILABILITY
Phytate
(Myo inositol hexaphosphate)
Using RNAi Technology to: 1. Suppress the synthesis of Phytate (MIK suppression) 1. Modulate expression of transporter gene
(MRP suppression)
Fe
Fe
Zn
Zn Ca
Ca
Raw Flour Porridge Fermented
Flour
Fermented
porridge
TG Low
Phytate 1 664 (46%) 703 239 196
TG Low
Phytate 2 911 (26%) 960 34 64
TG Low
Phytate 3 749 (39%) 722 233 121
NC 1 1245 1117 133 127
NC 2 1227 1212 591 550
Effects of Traditional Food Processing
(Porridge Making and Lactic Fermentation)
on the Phytate Content of ABS sorghum (mg/100 g)
with reduced phytate (MIK suppression)
Kruger, J, Taylor, JRN, Oelofse, A. 2012.
Food Chem. 131: 220
Raw flour Porridge LAB
Fermented
Flour
LAB
Fermented
_Porridge
TG Low
Phytate
13.3 8.9 28.7 30.0
NC 12.8 10.6 15.3 17.6
Effects of Traditional Food Processing on the Iron Bioavailability
(in vitro dialysability assay) ( %) of ABS sorghum
With Reduced Phytate
(MIK Suppression)
Kruger, J, Taylor, JRN, Oelofse, A. 2012.
Food Chem. 131: 220
Bioaccessibility
(Dialysability
assay)
Uptake
(CaCo-2
pH 2)
Uptake
(CaCo-2
pH 4)
Rat pup
absorption
assay
TG1 13.2 0.98 0.81 75.9
NC1 5.2 0.95 0.70 70.7
TG2 15.1 0.89 0.73 83.3
NC2 9.5 0.76 0.94 68.8
TG3 15.7 0.93 0.82 74.3
NC3 6.6 0.78 0.70 69.8
WTC 6.7 0.82 0.73 66.3
Iron Bioaccessibility, Uptake and Absorption as
assayed by dialysability, Caco-2 uptake and
Suckling Rat Pup Model (%)
of ABS Sorghum with very low Phytate (MRP suppression)
Kruger, J, et al. 2013. Food Chem. 141: 1019
Confined Field Trial of ABS Sorghum in Nigeria Photo – Dr Florence Wambugu (ABS project director)
ABS PROJECT STATUS
BIOFORTIFICATION BENEFITS
• Meta-analysis of Actual Impact of Quality Protein Maize 12% increase in growth in weight and 9% increase in growth in height compared to normal maize in infants and young children (based on 9 studies) Gunaratna, NP et al. 2010. Food Policy 35:202
• Potential Impact of Golden Rice in India
Calculated on Disability Adjusted Life Years, Golden Rice could more than halve Vitamin A deficiency disease burden and be very cost effective Stein AJ et al. 2007. World Development 36:144
IN STUDIED AREA OF RURAL BURKINA FASO IF ALL THE CURRENT INTAKE OF CEREALS WAS REPLACED
BY THESE BIOFORTIFIED CEREALS How would it impact on the Nutritional Status of the Young Children?
• Only Vitamin A status or Quality Protein intake would be substantially improved • Vitamin A maize and QPM Maize are biofortified with only one nutrient • Proportion of the other cereals in the diet: Sorghum, Pearl
Millet, Rice and Wheat is too low to make any real difference From: Taylor, Janet, Taylor, JRN, Kini, F. 2012. Cereal Foods World 57: 165
BIOFORTIFICATION CHALLENGES
• Malnutrition is seldom just about one nutrient
• Agronomic characteristics are Paramount
• Consumer acceptability of foods
• Seed Supply Systems are an Essential
• High costs of development
• Legislative approval (GM)
• Cash Crop Value
• Getting all the stakeholders to work together
Provitamin A rich ABS Sorghum Photo – From Dr Florence Wambugu
Director ABS project
ACKNOWLEDGEMENTS Co-workers from:
Africa Harvest Biotechnology Foundation International
Pioneer Hi-Bred, UC Davis, HarvestPlus Foundation, CSIR
IRSS Burkina Faso and University of Pretoria
Financial support: