Influence of high-hydrostatic pressure on tryptic and chymotryptic hydrolysis of milk proteins

Abstract

This work describes the effect of isostatic pressure 500 MPa on tryptic and chymotryptic hydrolysis of α- and β-casein, bovine serum albumin (BSA), β-lactoglobulin (β-Lg) and α -lactalbumin (α-La). Digestion was also conducted at atmospheric pressure. The extent of hydrolysis and peptide profiles were analysed by gel-permeation and reverse-phase high-performance liquid chromatographies. The residual immunochemical reactivities of the protein hydrolysates were assessed by the Streptavidin ImmunoCAP system (Phadia) for determination of specific immunoglobulin type E (IgE) antibodies. We have found very significant changes of the peptide profiles and a progressive reduction in residual-intact proteins after applying high pressure during tryptic proteolysis of β-Lg and BSA and chymotryptic proteolysis of β-Lg, α-La and BSA. A statistically significant decrease of the residual immunochemical reactivities of β-Lg tryptic and α-La chymotryptic hydrolysates prepared under high pressure, in comparison with the control samples hydrolysed at atmospheric pressure, was also observed.