Effect of Some Chelating Agents, Emulsifiers and Salts on Rehydration and Microstructure Properties of Skim Milk Powder

Poor rehydration properties of skim milk powder (SMP) can impact processing efficiency and functionality in final product formulations. In this study, the effects of adding lecithin (1%) and tween 80 (0.1%) as emulsifiers, di sodium EDTA and sodium citrate dihydrat (SCD) each one 5 mM as chelating agents, NaCl (0.08%) and CaCl2 (0.01%) as salts in improving rehydration characteristics of the product were investigated. These compounds were added to skim milk prior to spray drying and the effects of them on rehydration properties (wettability, dispersibility and solubility), microstructure and chemical properties of SMP were determined. Tween 80, EDTA and CaCl2 had a greater effect on improvement of the rehydration properties compared to other compounds. Tween 80 and CaCl2 also led to higher uniformity in the microstructure of SMP. Overall, the findings suggest that application of tween 80 combined with EDTA and CaCl2 might be an effective technique for improving SMP rehydration properties during reconstitution process.