- The whey protein beta-lactoglobulin has been proposed as a transporter for covalent bound bioactive compounds in order to enhance their stability and reduce their sensory perception. The garlic derived compounds allicin and diallyl disulfide were bound covalently to the native and heat denatured protein. The binding site and the influence of the modification on the digestibility were determined by mass spectrometric analysis of the modified beta-lactoglobulin. Further, the conformation of the modified protein was assessed by circular dichroism and dynamic light scattering. The free thiol group of Cys(121) turned out to be the major binding site. After proteolysis with trypsin at pH 7 but not with pepsin at pH 2, a limited transfer to other cysteinyl residues was observed. The covalently bound ligands did not mask any proteolytic cleavage sites of pepsin, trypsin or chymotrypsin. The modified beta-lactoglobulin showed a native like conformation, besides a moderate loosening of protein folding. The covalent binding of organosulfurThe whey protein beta-lactoglobulin has been proposed as a transporter for covalent bound bioactive compounds in order to enhance their stability and reduce their sensory perception. The garlic derived compounds allicin and diallyl disulfide were bound covalently to the native and heat denatured protein. The binding site and the influence of the modification on the digestibility were determined by mass spectrometric analysis of the modified beta-lactoglobulin. Further, the conformation of the modified protein was assessed by circular dichroism and dynamic light scattering. The free thiol group of Cys(121) turned out to be the major binding site. After proteolysis with trypsin at pH 7 but not with pepsin at pH 2, a limited transfer to other cysteinyl residues was observed. The covalently bound ligands did not mask any proteolytic cleavage sites of pepsin, trypsin or chymotrypsin. The modified beta-lactoglobulin showed a native like conformation, besides a moderate loosening of protein folding. The covalent binding of organosulfur compounds to beta-lactoglobulin provides a bioactive ingredient without impairing the digestibility and functional properties of the protein. (C) 2015 Elsevier Ltd. All rights reserved.…
