Browsing by Author "Demeke Teklu"

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    Nutritional Quality, Response to Agronomic Biofortification, and Mineral Bioaccessibility of Finger Millet Genotypes
    (Addis Ababa University, 2023-09) Demeke Teklu; Dawd Gashu
    Micronutrient deficiencies (MNDs), also known as hidden hunger, affect more than a quarter of the global population. Agronomic biofortification helps to increase the concentration of a target mineral in food crops and improve human mineral dietary intake. It is a means of providing nutrient-dense foods to a larger population, especially among rural resource-poor settings, providing that they have access to mineral fertilizers. However, the feasibility of agronomic biofortification in combating hidden hunger depends on several factors in addition to fertilizer access, including crop type, genotype, climate, soils, and soil mineral interactions. Consideration of its effectiveness in increasing human mineral intake to the daily requirements and the improvement of human health and the cost-effectiveness of the program is also important. In this paper, we review the available literature regarding the potential effectiveness and challenges of agronomic biofortification to improve crop micronutrient concentrations and reduce hidden hunger.
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    Nutritional Quality, Response to Agronomic Biofortification, and Mineral Bioaccessibility of Finger Millet Genotypes
    (Addis Ababa University, 2023-09) Demeke Teklu; Dawd Gashu
    Background: High prevalence of zinc (Zn) and iron (Fe) deficiencies which a public health concern in Ethiopia are predominantly a result of cereal based diet with less dense nutrient content. Agronomic biofortification increases micronutrient concentration in the edible part of food crops through the application of mineral fertilizers. But for agronomic biofortification strategy to be effective, targeting food crops and varieties known to adapt in local environment and has a good nutritional quality is important. In addition to the increase in grain mineral concentration in response to agronomic biofortifcation, bioavailability of this mineral to the body system is cruicial. Objectives: To evaluate the nutritional quality, investigate response to agronomic biofortification and bioaccessibility of different finger millet genotypes of Zn and Fe. Methods: Fifteen improved genotypes of finger millet were evaluated for their proximate composition, mineral and antinutrient concentration, and mineral bioavailability. Three of these genotypes were then agronomically biofortified with Fe and Zn at two locations (Gojjam and Arsi Negelle) and two slope positions (foot and hill). The genotypes were evaluated for their response towards yield, grain Fe, Zn and antinutrient concentration. Fe and Zn bioaccessibilty was also evaluated. Result: There was significant variation in protein, fat, fibre, total minerals ranging from 10 to 14.67%, 1.05 to 3.81%, 1.44 to 4.63% and 1.01 to 3.97 %, respectively, as a result of genotypic differences. Similarly, finger millets genotypes had significantly different mineral and antinutritional concentrations ranging from 3762 ±332 to 5893 ±353 mg kg-1 for Ca, 19.9 ±1.6 to 26.2 ±2.7 mg kg-1 for Zn, 36.3±4.6 to 52.9±9.1mg kg-1 for Fe, 36.6 ±11 to 60.9 ±22 μg kg-1 for Se, 311.5±2.9 to 341.4±19.9 μg g-1 for phytate, 0.16±0.01 to 0.5±0.01 mg g-1 for tannin and 1.34±0.2 to 3.39±0.8 mg g-1for oxalate. The combined soil application of Fe and Zn to Meba genotype, Zn to Urji genotype and Fe to Diga-01 genotype increased yield by 51.6, 27.6 and 18.3 %, respectively. Furthermore, grain Zn concentration increased by 18.9 and 20% in response to soil application of combined Fe and Zn and only Zn, respectively. Similarly, 21.4 and 17.8% increase in grain Fe concentration was observed as a result of combined Fe and Zn and only Fe application, respectively. Location but not slope position was a source of variation for both grain Zn and Fe concentrations. Fertilizer treatment showed a significant (p <0.001) variation in Zn bioavailability expressed as a total available Zn (TAZ) ranging from 0.51 to 2.57 mg 300 g-1. Bioaccessible fraction of Zn and Fe increased up to 81 and 88%, respectively, and phytate concentration reduced up to 49% as a result of fermentation. Fermentation of agronomically biofortified finger millet could potentially contributes up to 126% for adult men and 90% for adult women to the total absolute daily Fe requirements, assuming that a person consumes 300g/day in a dry base. Similarly, up to 179% for adult men and 251% for adult women of recommended daily intake of Zn could be fulfilled from agronomically biofortified and fermented finger millet. Conclusion: Iron and Zn agronomic biofortification could be an effective approach to improve yield, grain mineral concentration as well as their relative bioavailability. It could help to combat Fe and Zn deficiencies through increasing the consumption of more bioavailable Zn and Fe among the society special where finger millet is cultivated as a staple crop. The result suggests that finger millet breeding program should focus on evaluation of nutritional quality alongside agronomic traits. Future studies as well as development programs on agronomic biofortification should consider genotypic and environmental (location and slope position) effects beside the main fertilizer effect, which is a gap in current knowledge base.