Extrusion cooking of food-to-food fortified wholegrain sorghum-based porridges enhances Caco-2 ferritin formation

Abstract

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 conventionally-cooked, 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.