Development of an extruded micronutrient delivery vehicle for the fortification of nixtamalised maize with chelated iron at the point of wet milling

The use of high-temperature extrusion for the development of a micronutrient delivery vehicle (MDV), made of rice and maize (1:1 w/w), as part of a fortification technology for traditional nixtamalised maize (NM) masa at the point of use was evaluated. A Welly puffing extruder and a peristaltic pump were used to establish a uniform extrusion process for MDVs containing 302 ± 13 mg kg^-1 of NaFeEDTA or 656 ± 8 mg kg^-1 of ferrous bisglycinate. After manual premixing (30 s) of MDVs with NM (1:20 or 1:40 MDV:NM) and grinding with a pilot scale burr mill (5 min), iron distribution in masa was variable, ranging 3-21% RSD within sections of individual 2-kg batches. Kneading (5 min) shortly after grinding resulted in uniformed iron distribution (<4% RSD). Despite the iron source and fortification level, fortified NM masa was harder and darker than control after 8-h storage at room temperature; however, these changes require further sensory evaluation.