Abstract: Whey protein isolate,WPI,was hydrolyzed using Protease N“ Amano” G(IUB 3.4.24.28)in a batch reactor at 55℃ and pH7.0 according to the pH-stat procedure.Ash was removed by adsorbing the hydrolysates onto macroporous adsorption resins(MAR).Desorption was achieved by washing with 20%,40% and 75% alcohol(V/V)respectively and three fractions:HS20,HS40 and HS75 corresponding to the alcohol concentrations used in desorption were obtained.They were assayed for surface hydrophobicity(SH0),angiotensin-I converting enzyme(ACE)inhibition,emulsifying activity index(EAI),total amino acid composition and molecular weight distribution.Fraction HS75 showed superior ACE inhibition effect(lowest IC50),with highest content of hydrophobic and essential amino acids and contained about 71% less 600Da with no fractions exceeding 4142Da.Additionally;the hydrolyte showed the objectionable bitterness.Desorption with alcohol reversed the solvent antagonism,weaken hydrophobic interaction forces between the peptides and resins and hence to elute the peptides.

Key words: desalt, debitter, macroporous adsorption resin, hydrophobicity, whey protein hydrolysate