There is a growing awareness today about climate change and its expected ravaging effects on agricultural productivity, food production and ultimately, food and nutrition security. Against this backdrop, drought-tolerant hardy crops are gaining importance as significant sources of food and nutrition especially in the most vulnerable parts of the world mainly in sub-Saharan Africa and Asia. In this regard, the millets, which are major cereal staples in many parts of Africa and Asia are of importance for food and nutrition security in these regions. Millets are processed into various foods using traditional processing methods such as fermentation and malting and modern technologies such as extrusion cooking. This chapter focuses on how these processing methods can enhance the nutritional properties of millet-based foods. The simple practice of compositing millets with other plant foodstuffs for enhanced nutritional quality of millet-based foods is also explored.

Background and Objectives: Iron deficiency is still a major public health concern in sub-Saharan Africa, and this is in part due to a monotonous diet of cereals often low in bioavailable minerals and high in mineral bioavailability inhibitors, notably phytate and polyphenols. Sorghum is a major food crop across the semi-arid tropics in Africa because of its tolerance to high temperature and low rainfall. Extrusion cooking is a process that applies high heat, pressure, and shear to raw food materials to produce ready-to-eat products. The application of high heat, pressure, and shear can destroy anti-nutrients in plant foods and hence enhance the bioavailability of minerals. Food-to-food fortification (FtFF) is a strategy where micronutrient-rich food combinations are used to promote the bioavailability of essential micronutrients by increasing the content of micronutrient bioavailability enhancers. The objective of this study was to determine the effects of extrusion cooking of wholegrain sorghum-based porridges fortified with baobab fruit powder and moringa leaf powder on iron bioaccessibility. Findings: Although extrusion reduced bioaccessible iron content (BIC) and percentage bioaccessible iron (PBI), it enhanced ferritin-formation in Caco-2 cells (by 38%) compared to conventional cooking, most probably because extrusion reduced contents of phenolics and phytate, hence freeing more iron. Fortification with baobab increased PBI by 14%-34% whether extruded or conventionally cooked, probably due to its organic acids. Fortification with moringa reduced BIC and PBI (by 30% and 71%, respectively) whether extruded or conventionallycooked, probably due to its high calcium and phytate contents. Conclusion:Extrusion cooking has the potential to help alleviate iron deficiency in sorghum-based foods because it reduces the content of anti-nutrients.Significance and Novelty: This study highlights the potential of extrusion cooking coupled with fortification with tropical foodstuffs high in organic acids to improve iron bioavailability in wholegrain-based starchy staple foods.