What is the change in color in testing for the presence of protein in egg albumin using solution sodium hydroxide and copper sulfate?

Copper sulphate when mixed with a protein will turn purple if the amount of protein is sufficient enough in quantity to trigger the reaction. Planex1234 says; No offense but i think it is starch that turns dark blue - purple. Thetada says: the colour changes are arguably similar. Iodine solution goes blue/black in the presence of starch. The colour that sodium hydroxide / copper sulphate solution goes in the presence of protein is variously described as mauve / purple.