The strength of attachment of adsorbed bovine β-lactoglobulin (βlg) and acetylated β-lactoglobulin (Ac-βlg) has been studied by comparing the elution profiles of the adsorbed proteins. βlg binds very loosely to alumina at pH 4.2 and both βlg and Ac-βlg bind very tightly to alumina at pH 5.1 where the proteins showed highest adsorption at alumina/ water interface [ Bhaduri, A & Das, K. P., J. Disp. Sci. Technol., 15, 165-188 (1994)]. Adsorbed protein can only be eluted out if the pH of the elution buffer is raised to 7.6. βlg elutes as a single peak whereas Ac-βlg as two peaks indicating the later is adsorbed to alumina with different affinities. Elution profile of adsorbed βlg at pH 6.3 shows that adsorbed βlg population consists of partly folded elutable fraction and partly unfolded resistant one. The interaction of first layer of protein with the silica surface at pH 5.1 is primarily hydrophobic for βlg and electrostatic for Ac-βlg.