The effect of extrusion cooking on iron absorption from maize and potato

Maize and potato samples were extruded at high temperature (120–140°C) and pressure (500–900 p.s.i.) and the effect on Fe absorption was measured by whole body counting in rats using 59Fe as an extrinsic label. The equipment used in the extrusion process considerably increased the Fe content of the products but the processing itself had no effect on % Fe absorption: maize, non‐extruded 59.6 (SEM 1.5), extruded 59.9 (SEM 1.7); potato, non‐extruded 41.5 (SEM 1.5), extruded 35.5 (SEM 2.8). A similar percentage of Fe was absorbed from a commercially available extruded maize snack: 63.0 (SEM 1.2). The Fe in maize was 85.90% and in potato 70.82%, as well absorbed as Fe from FeSO4. These studies indicate that extrusion cooking has no effect on the amount of Fe absorbed and that any Fe picked up in the extrusion process is as available for absorption as the endogenous Fe in the food.