Pressure-induced denaturation of β-lactoglobulin in skim milk: effect of milk concentration.
The effect of milk concentration (10-40% TS) on the kinetics of the pressure-induced denaturation of β-lactoglobulin (β-LG) was studied. The denaturation was found to be a second-order process at all milk concentrations and pressures. There was a change in pressure dependence of the rate constants for denaturation at about 300 MPa, and this effect became more pronounced as the milk concentration increased. At pressures ≥300 MPa, a small effect of milk concentration was observed, with small decreases in the rate of denaturation as the milk concentration was increased above 20% TS. This was attributed to the lower pH as the milk concentration was increased. In contrast, at 200 MPa, β-LG denaturation was markedly retarded as the milk solids concentration was increased. This was attributed to the increased lactose concentration at higher milk concentrations. This would promote β-LG dimerization at this pressure and this would stabilize the β-LG to denaturation.
Fonterra Research Centre, Palmerston North, New Zealand. skelte.anema@fonterra.com
Skelte G
SG
Anema
D000818:Animals; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007782:Lactoglobulins / Q000737:chemistry*; D007785:Lactose / Q000032:analysis; D008892:Milk / Q000737:chemistry*; D011312:Pressure; D011489:Protein Denaturation
D007782:Lactoglobulins; D007785:Lactose