High pressure-induced changes in bovine milk proteins: a review.
High pressure (HP)-induced changes in the proteins of bovine milk have become an area of considerable research interest in recent years; as a result, there is now a detailed understanding of the effects of HP on casein micelles and whey proteins. HP treatment at pressures >400 or >100 MPa denatures the two most abundant whey proteins, alpha-lactalbumin (alpha-la) and beta-lactoglobulin (beta-lg), respectively. The majority of denatured beta-lg in HP-treated milk associates with the casein micelles, although some denatured beta-lg remains in the serum phase or is attached to the milk fat globule membrane; HP-denatured alpha-la is also associated with the milk fat globules. Casein micelles are disrupted on treatment at pressures >200 MPa; the rate and extent of micellar disruption increases with pressure and is probably due to the increased solubility of calcium phosphate with increasing pressure. On prolonged treatment at 250-300 MPa, reassociation of micellar fragments occurs through hydrophobic bonding; this process does not occur at a pressure >300 MPa, leading to considerably smaller micelles in such milk. As a result of HP-induced changes, the size, number, hydration, composition and light-scattering properties of casein micelles in HP-treated milk differ considerably from those in untreated milk.
Huppertz
Thom
T
Department of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
Fox
Patrick F
PF
de Kruif
Kees G
KG
Kelly
Alan L
AL
D000818:Animals; D002364:Caseins / Q000737:chemistry; D002417:Cattle; D008823:Micelles; D008894:Milk Proteins / Q000737:chemistry*; D011312:Pressure; D011487:Protein Conformation; D000067816:Whey Proteins
D002364:Caseins; D008823:Micelles; D008894:Milk Proteins; D000067816:Whey Proteins