Effect of extrusion conditions on iron stability and physical and textural properties of corn snacks enriched with soybean ferritin

Soybean sprouts cultured in 20mm FeSO4 were introduced into corn snacks (1.75-3.50%) to supplement iron. The effect of extrusion process on the ferritin iron stability and on product quality was studied. Iron stability in these fortified snacks depended mainly on feed moisture levels, with the best results seen when the feed moisture and temperature were 12% and 110 degrees C, respectively. Lower feed moisture was beneficial to hardness, expansion ratio and bulk density, while lower temperature increased snack hardness and density, while worsening the expansion ratio. The snacks' water absorption was strongly and directly dependent on the temperature, while their solubility mainly depended inversely on feed moisture. All of the variables tested altered the colour of the snacks. The conditions that were best for producing the ferritin-fortified snacks - 12% feed moisture, and temperature equal than or less to 140 degrees C - may yield a product with the desired quality features.