Solutions of 10% WPI or glycomacropeptide standard (Davisco Foods, Le Seuer, MN, USA) were prepared in acetonitrile buffer with trifluoroacetic acid (400 mL acetonitrile, 600 mL milliQ H20, and 1mL trifluoroacetic acid) and filtered through a 0.45 mmfilter. The column was eluted with the same buffer at a flowrate of 0.6 mL$min?1 using a Waters 515 HPLC pump (Waters Corporation, Franklin, MA, USA). Proteinwas detected by absorbance at 215 nm using aWaters 2996 photodiode array detector or a Waters 410 refractometer to determinethe relative abundance of themajorwhey proteins in each WPI.