Effect of high pressure treatment on egg white protein digestibility and peptide products

The effect of high pressure treatment on whole egg white was examined using in vitro pepsin digestion and proteomic methods. Pepsin incubations conducted with an enzyme to protein ratio of 3:1 following high pressure treatment (400-800 MPa and 9 C) resulted in increased hydrolysis of egg white proteins. Pressure treatment of egg white at 800 MPa resulted in greater susceptibility to pepsin hydrolysis than did thermal treatment at 95 C. The effect of 800 MPa pressure treatment on egg white proteins was additionally examined by incubation with pepsin at an enzyme to protein ratio of 1:20 followed by 2-D electrophoresis. Results of these experiments showed extensive hydrolysis of most egg white proteins. Subsequent LC-MS/MS investigation of the low M _r fraction (< 3.0 kDa) derived from pepsin digested 800 MPa treated egg white contained numerous peptides previously shown to have bioactive and/or immunological properties. Industrial Relevance Short time high pressure treatment of whole egg white at relatively low temperature (9 C) resulted in increased pepsin digestibility equivalent to or better than heat treatment at 95 C. Examination of the peptides resulting from high pressure treatment and pepsin digestion revealed sequences with known biological activities. Thus high pressure treatment represents a promising technology for enhancing egg white's healthiness and contributing to its role as a functional food.