Iron Fortified Yoghurt: Effect of Different Iron Salts on the Properties of Yoghurt

Yoghurt is considered as the best and the most complete food, but it is deficient in iron and by fortification yoghurt iron can reach for most consumers. Four different iron salts were used (iron amino acid chelate (T1), ferrous sulfate (T2), ferrous fumarate (T3), and ferric hydroxide poly maltose (T4)) for fortification of such yoghurt. Chemical properties, acidity, lactic acid bacteria, yeasts, rheology, viscosity, peroxide number and sensory properties were evaluated at zero time, after 3 days and after 7 days of manufacturing. Total solids were increased by iron salts, especially in T1 and T4 treatments followed by T3 and the T2. The T2 was the highest treatment in ash content, while the protein content was higher in T1 and the T4 in contrary to protein contents in T2 and T3 that did not affect by adding iron salts. In all treatments, fat contents did not affect by the addition of iron. The T1 and T3 had the lowest acidity, while theT2 and T4 were the highest however, the acidity in the control lie between them. The peroxide numbers for yoghurt belongs to different treatments were estimated after the cold storage for 7 days and ranged between 0.65 meq O2/kg in T4 and 0.98 meq O2/kg in the T2. The peroxide number in T1, T3 and T4 were lower than the peroxide number in the control. All different samples are accepted by panelists. In conclusion, iron can be added to yogurt in different forms without affecting the characteristics of resultant yoghurt with preference the 1st treatment (i.e. yoghurt Fe fortified by amino acid chelate).