The expansion of the agricultural activity in Brazil brings in it problems of environmental order concerning to the large quantity of residues produced such as whey. This lacteous by-product is rich in proteins of high biological value and the study of its technological properties and its incorporation in food emulsions would contribute to the aggregation of the value to itself. The technological properties (capacity of hydration and of retention of water, emulsifier and foam forming proprieties) of a WPC were evaluated. It was verified that the best results to the capacity of hydration and the emulsifier were obtained in pH 7, in concentration of 0,1 g% while the emulsion was more stable in pH 6. It was observed a higher formation of foam in the concentration 2 g% of protein in the pH 3 and 7, although has itself been more stable in pH 3, in the protein concentration of 1,4 g%. Those results were associated to the fact of in the values of the pH mentioned, the proteins were electrically charged which would increase its solubility and consenquently its foam forming, hidration and emulsifier capacities. The best stability would be achieved in that pH in which the electric charges besides soluble, allowed that the proteins remained in the water-oil or water-air interfaces. In the evaluated conditions, the pH and the protein concentration have had significant effect on the technological properties of WPC.