摘要：Whey from Edam cheese manufacture was concentrated by ultrafiltration (Concentration factor 20) and Whey Protein Concentrate (WPC) was fractionated into β-lactoglobulin (β-Lg) and α-lactalbumin (αLa) rich fractions by two different methods. The composition, emulsifying capacity and stability and foam capacity and stability of WPC and its fractions were determined. Also, the viscosity of WPC and β-Lg and α-La rich fractions were followed as affected by the addition of different concentrations of NaCl and CaCl2. The results indicated that the yield and composition of the prepared fractions by the two methods were not identical. However, β-Lg fraction showed higher Emulsifying Capacity (EC) followed by (α-La) rich fraction compared with lowest EC for the original WPC solution. On the other hand, emulsion stability of WPC and its fractions was nearly the same. The foaming capacity of WPC, β-Lg and α-La increased slightly with increasing whipping time up to 15 min. α-La rich fraction showed the lowest foam capacity, as compared to β-Lg and WPC. Addition of sodium chloride decreased the viscosity of solutions of WPC and its fractions solutions with a linear relation between the NaCl concentration and the decrease in the viscosity. Addition of NaCl up to 50 mg/100 mL increased slightly the viscosity of β-Lg solution but further increase of NaCl decreased its viscosity. Addition of CaCl2 was found to increase the viscosity of WPC solution reaching a maximum when 60 mg CaCl2/100 mL and then decreased on further increase in the added CaCl2. The viscosity of α-La solutions with different NaCl contents decreased with the increase in temperature. Also, addition of CaCl2 up to 60 mg/100 mL to α-La solution increased its viscosity.
