FONIO (DIGITARIA EXILIS) IN WEST AFRICA: TOWARDS IMPROVING NUTRIENT QUALITY IMPROVING NUTRIENT TOWARDS AFRICA: WEST EXILIS) IN FONIO (DIGITARIA INVITATION You are cordially invited to attend the ceremony of my PhD thesis defence entitled FONIO (DIGITARIA EXILIS) IN WEST AFRICA: TOWARDS IMPROVING NUTRIENT QUALITY On Tuesday, 8 September 2015 at 4:00 p.m. at the Aula of Wageningen University Generaal Foulkesweg 1a, Wageningen The ceremony will be followed by a reception in the Aula Yara Koréissi Yara Koréissi 2015 Yara [email protected] Paranymphs Lucy Elburg Yara Koréissi [email protected] Esmee Doets [email protected] Fonio (Digitaria exilis) in West Africa: Towards improving nutrient quality Yara Koréissi Thesis committee Promotor Prof. Dr M.B. Zimmermann Professor of Micronutrients and International Health,Wageningen University Professor of Human Nutrition, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland Co-promotors Dr I.D. Brouwer Associate professor, Division of Human Nutrition Wageningen University Dr D. Moretti Senior Scientist Swiss Federal Institute of Technology (ETH) Zurich, Switzerland Other members Prof. Dr C. de Graaf, Wageningen University Dr C. Mouquet-Rivier, Institut de Recherche de Developpement, Montpellier, France Dr C. Cercamondi, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland Prof. B.R. Hamaker, Purdue University, West Lafayette, USA This research was conducted under the auspices of the Graduate School VLAG (Advanced studies in Food Technology, Agrobiotechnology, Nutrition and Health Sciences). Fonio (Digitaria exilis) in West Africa: Towards improving nutrient quality Yara Koréissi Thesis submitted in fulfilment of the requirements for the degree of doctor at Wageningen University by the authority of the Rector Magnificus Prof. Dr A.P.J. Mol, in the presence of the Thesis Committee appointed by the Academic Board to be defended in public on Tuesday 8 September 2015 at 4 p.m. in the Aula. Yara Koréissi Fonio (Digitaria exilis) in West Africa: Towards improving nutrient quality 180 pages. PhD thesis, Wageningen University, Wageningen, NL (2015) With references, with summary in English ISBN 978-94-6257-455-7 Abstract Hidden hunger affects a far greater percentage of the world’s population with iron and zinc deficiencies being the most common, particularly affecting women of reproductive age. The primary cause of the mineral and vitamin deficiencies in developing countries is inadequate intakes of multiple and bioavailable micronutrients in common cereal- based diets, emphasizing the need for increased quality of diets. Plant genetic diversity, and also indigenous foods and/ or traditional grains as fonio may play a critical role in reduction of the problem for resource poor populations. Fonio (Digitaria exilis) is the most ancient West African cereal representing a key crop in food supply during crop shortfall periods. However, less is known about its potential to contribute improving nutrition and health. In this context, the thesis investigated whether the nutrient quality of fonio, especially iron, could be improved to potentially contribute to the daily intake of the population. Research was done in the framework of the EU funded FP6 Fonio project. Investigations in this thesis comprised: i) the consumption pattern of fonio and its contribution to nutrient intakes (24 hr recall among 108 women aged 15-49 year-old, Bamako, Mali); ii) the validation of the Mali food composition database (TACAM) for assessing population level intakes of energy and nutrients (weighed food record and chemical analysis of duplicate portion among 36 women out of 108 previously selected); iii) the genetic diversity, nutrient content especially bioavailable iron and zinc content and the effect of processing on fonio landraces (chemical and amplified fragment length polymorphism analysis of 12 Malian fonio landraces); iv) the sensory variability among fonio landraces (sensory analysis of 20 fonio landraces from Mali, Guinea and Burkina Faso); v) improved food processing combining dephytinisation with native phytase and fortification of fonio diet with iron to increase iron absorption (iron absorption stusy among 16 women aged 18-30 years, Cotonou, Benin). The results indicated that fonio is consumed one to three times/month by 68% of our study population with an average daily portion size of 152g when consumed. Only 5% of the study population consumed fonio dishes contributing to 16% of the daily energy intake for the consumed portion size, reflecting the low consumption of fonio related to significant barriers such as availability of cooked fonio in urban markets, lack of consistent supply throughout the year, difficult post- harvest processing, high-quality product demand, hard texture coupled with time consuming cooking process, and high cost of fonio products. The use of the adjusted TACAM is acceptable for estimating average intake at population level for macronutrients, calcium and zinc in a low intake population, but not for carbohydrate and iron intakes which were underestimated and vitamin A which was overestimated, nor for probability of adequate intakes and nutrient densities. At individual level, significant differences were observed between estimated and analyzed intakes for all the nutrients increasing with higher intakes. 5 | Page Fonio landraces in West Africa were different for their visual (colour and presence/absence of impurities) and their textural (consistency of cooked grain) charactersitics. We found no meaningful genetic diversity among the 12 landraces in Mali (indicated by the very low polymorphism level of 3.5%) and the proximate composition, iron and zinc content showed no significant differences among landraces. Traditional processing reduced iron (96% reduction) and phytate (75% reduction) content, however, the molar ratio of phytate to iron remained above the critical cut-off of >1 indicating poor iron bioavailability. Zinc concentration was hardly affected by processing and cooking. Processing experiments confirmed that whole wheat flour is a good source of natural phytase to produce low phytic acid containing fonio porridge. Dephytinisation using intrinsic wheat phytase reduced phytate-to-iron molar ratio from 24:1 to 3:1 after only 1 hour of incubation at 50ºC with pH of 5.0, and iron fortification further reduced the molar ratio to 0.3:1. Dephytinisation with wheat phytase and fortification significantly increased iron absorption ratio from 2.6% to 8.2% in fonio porridges. We conclude that the current contribution of fonio to daily bioavailable iron intake is low due to small portion sizes being consumed in low frequency, to considerable losses during processing to mid-wet fonio, and to a high phytate-iron molar ratio. Fonio landraces from Mali, Guinea and Burkina Faso are variable in visual and textural characteristics (colour, presence of impurity and consistency of the cooked grain, respectively), determining the preference of consumers. Selecting landraces for preferred sensory properties may offer an entry point for processors who intend to promote the consumption of fonio and increase its role in diet. In absence of meaningful genetic diversity and variation in iron content in fonio landraces in Mali, there is little benefit in selecting landraces for natural high iron content. Dephytinisation using intrinsic wheat phytase could be a promising processing practice to improve iron bioavailability and fortification is required to increase the amount of absorbed iron from fonio meals. 6 | Page Table of Contents Chapter 1 9 General introduction Chapter 2 35 Consumption of, and beliefs about fonio (Digitaria exilis) in urban areas in Mali Published in African Journal of Food Agriculture Nutrition and Development 2009,9(9):1927-44 Chapter 3 51 Evaluation of food composition databases in low to middle income countries: the Mali food composition table Submitted for publication Chapter 4 75 Fonio (Digitaria exilis) landraces in Mali: Nutrient and phyate content, genetic diversity and effect of processing Published in Journal of Food Composition and Analysis 2013,29(2):134-43 Chapter 5 99 Sensory diversity of fonio landraces from West Africa Published in African Journal of Biotechnology 2013,12(15):1836-44 Chapter 6 117 Dephytinisation with intrinsic wheat phytase and iron fortification significantly increase iron absorption from fonio (Digitaria exilis) meals in West African women Published in PloS ONE 2013,8(10):e70613:doi 10.371/journal.pone.0070613 Chapter 7 139 General discussion Et cetera 165 Summary, Ackowledgements, About the author 7 | Page 8 | Page 11 ChapterChapter oneone -- GeneralGeneral iintroductionntroduction 99||PagePage BACKGROUND The role of biodiversity in improving micronutrient deficiencies Maternal and child malnutrition remains a pervasive and damaging public-health problem in many low- and middle-income countries affecting billions of people. To date, over 165 million children under five years of age are stunted (too short for their age) and about 52 million children are wasted (too thin) and thus require special treatment [1]. Maternal under nutrition, indicated by the prevalence of low BMI among adult women (<18.5 kg/m2), remains above 10% in Africa and Asia [1]. In addition to undernourishment, there is rising concern about the quality of diets in terms of adequate micronutrients in developing countries. Hidden hunger, which represents a lack of micronutrients, affects a far greater percentage of the world’s population with