EXTRUSION COOKING OF A HIGH-FIBER CEREAL PRODUCT .2. EFFECTS ON APPARENT ABSORPTION OF ZINC, IRON, CALCIUM, MAGNESIUM AND PHOSPHORUS IN HUMANS

The effect of extrusion cooking, using mild conditions, of a high-fibre cereal product on apparent small bowel absorption of zinc, iron, calcium, magnesium and phosphorus was studied. Seven ileostomy subjects were studied during two periods (each of 4 d), on a constant low-fibre diet supplemented with either 54 g/d of a bran-gluten-starch mixture or the corresponding extruded product. The apparent absorption of Zn, Mg and P was significantly decreased (P < 0.05) during the period with extruded product compared with the period with bran-gluten-starch. No difference was found for Fe and Ca. The negative effect of extrusion cooking of a product containing phytic acid on availabiity of Zn, Mg and P was small but could be of nutritional relevance in foodstuffs that are consumed frequently and in infant formulas.