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: