The Effects of High Pressure on Whey Protein Denaturation and Cheese-Making Properties of Raw Milk

Abstract

The effects of high pressure, from 100 to 400 MPa (14,500 to 58,000 psi) and applied for different periods (10 to 60 min), on the biochemical and microbiological characteristics of milk have been investigated. Particular attention was paid to modifications of the cheese-making properties. High pressure slightly improved the microbiological quality of milk without modifying the activity of native milk enzymes such as lactoperoxidase or plasmin. β-Lactoglobulin was denatured by pressures >100 MPa, but α-lactalbumin and bovine serum albumin were resistant to pressures ≤400 MPa for 60 min. Cheese yield, as estimated by centrifugation of curd, increased with pressurization at 300 and 400 MPa, reflecting incorporation of additional β-lactoglobulin and, especially, greater moisture retention. The coagulation time decreased as pressure increased ≤200 MPa and then increased again until at 400 MPa, reaching values comparable with those of the raw milk. High pressure treatment of milk can be an effective method for improving the coagulation characteristics of milk and for increasing the moisture retention of fresh cheese with a minimum of modification of other properties important for cheese making.