Effect of storage and baking on mineral contents of fortified whole wheat flour

Whole wheat flour fortified with relatively lower concentrations of sodium iron ethylenediaminetetraacetate (NaFeEDTA), elemental iron, ZnSO₄ and ZnO was evaluated for the changes in mineral content of fortified whole wheat flour during storage at ambient condition for 60 days. The chapattis (unleavened flat bread) prepared from fresh and stored fortified flours were assayed for iron, zinc, copper and manganese content to assess the effect of baking on these minerals. Addition of fortificants to the flours significantly increased iron and zinc content, and decreased the concentration of copper and manganese in these flours. Storage time did not significantly (P < 0.05) affect the intrinsic copper and manganese content of the flours in the presence of added iron and zinc. Chapattis made from stored flours manifested a nonsignificant effect of heat on mineral concentration in fortified flours for individual treatment. The mean values for the baking loss of copper and manganese in fresh and 60-day-stored flours were observed to be 2.22-3.46% and 1.69-2.97%, respectively. Similarly, such losses for iron and zinc content were 3.59-4.57% and 3.29-4.39%, respectively. NaFeEDTA was found to be the most susceptible form of iron fortificants during storage of flour. The stability of the micronutrient in the carrier is considered one of the key factors toward the success of any fortification program, as fortified flours may undergo physicochemical changes during storage and processing. Multiple fortification of whole wheat flour with novel iron and zinc sources is gaining popularity to overcome micronutrient malnutrition in the developing countries. Economic and nutritional aspects of such fortification programs require that the fortificants added to the flour are to be evaluated for their effect on the native components of the food, sensory attributes of the food and their availability in the final product during processing of the food. This study focused on measuring the extent of changes that might take place in the fortified flour during storage and baking of chapatti. It may also provide an understanding on the selection of fortificant source, storage stability and availability of the micronutrient in the processed food in any fortification program.