Microparticulated whey protein (MWP

Microparticulated whey protein (MWP) concentrate was kindly
supplied by Arla Foods Ingredients (Viby J, Denmark) and used without
further treatment. All chemicals used, including hydrochloric acid, sodium
hydroxide, sodium phosphate monobasic, sodium phosphate dibasic,
and Fluorescein isothiocynate (FITC) isomer I, were purchased
from Sigma-Aldrich (St Louis, MO, USA) and were of analytical grade.
Double distilled water was used as the solvent to prepare buffer solutions
and colloidal suspensions.