Effect of Extrusion Cooking on Acceptability, Nutrient Bioaccessibility and Anti-Nutritional Factors of Sorghum and Maize Flours Fortified With Iron and Zinc Salts
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Date
2016-06
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Addis Ababa University
Abstract
Food fortification stands out among public health intervention as one of the most effective method of preventing nutritional deficiency. Fortification refers to addition of nutrient to foods from which they were either absent or present in small amount to increase the intake of one or more nutrients. Effective fortification program aims to improve the bioavailable of nutrient intake of the whole population with the intent of eliminating or preventing micronutrient deficiencies in the general population and the most venerable groups. Being widely consumed, maize and sorghum flours are suitable vehicles for mass fortification. The main objective of this study was to investigate the effect of extrusion cooking on nutritional compositions, acceptability, level of anti-nutritional factors (phytic acid and tannin) and mineral bioaccessibility of sorghum and maize extrudates fortified with iron and zinc salts. Standard methods were used to analyze the proximate composition, anti-nutritional factors (phytic acid and tannin) and mineral bioaccessibility of the extrudates. The finding showed that fortification of maize and sorghum flours with iron and zinc salts prior to extrusion increased the mineral content of the extrudates produced at three extruding temperatures (110oC, 130 oC and 150 oC). Phytic acid decreased from 20% to 28% with increasing extruding temperature (p>0.05).The temperature of 150oC was found to be more effective and significantly reduced phytic acid than the lower temperature of 110 oC. Maize and sorghum unfortified extrudates relatively had higher soluble iron and zinc fraction. Increasing the extruding temperature caused increased the percentage of soluble iron fraction from 62.3% to 83.2% and 29.4% to 41.3% for unfortified maize and sorghum extrudates respectively. Soluble zinc percentage also increased from 17.2% to 42.6% and 65.2% to 98.4% for unfortified maize and sorghum extrudates respectively. Extrudates recorded lower sensory acceptability mainly in terms of their color and texture. Extrusion cooking is the ideal method for manufacturing a number of food products and permits the utilization and co-processing of various by products.
Keywords: Fortification; Bioaccessibility; Extrusion; Ferrous sulfate; Zinc sulfate
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Keywords
Fortification; Bioaccessibility; Extrusion; Ferrous sulfate; Zinc sulfate