title: Impact of α-lactalbumin:β-lactoglobulin ratio on the heat stability of model infant milk formula protein systems.
abstract: Model infant milk formula systems (5.5% protein) were formulated to contain α-lactalbumin:β-lactoglobulin ratios of 0.1, 0.5, 1.3, 2.1 or 4.6 and assessed for heat stability and heat-induced changes. 'Humanising' the model formulas by increasing α-lactalbumin:β-lactoglobulin enhanced heat stability at 140°C in the pH range 6.6-6.9. The model formulas were analysed after lab-scale high-temperature short-time heating at pH 6.8. Gel electrophoresis indicated that increased heat stability in high α-lactalbumin:β-lactoglobulin samples was due to decreased covalent interactions between proteins. In low α-lactalbumin:β-lactoglobulin formulas, protein-protein interactions caused marked increases in protein particle size and viscosity of the heated systems; conversely, covalent interactions between proteins were minimal in high α-lactalbumin:β-lactoglobulin formulas. Reduced protein-protein interactions with increasing α-lactalbumin:β-lactoglobulin has important implications for subsequent processing; for example, lower viscosity post-heating may affect bulk density in spray-dried products or physical stability in ready-to-feed products.
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Shane V
authors.initials: SV
authors.lastname: Crowley
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Aisling P
authors.initials: AP
authors.lastname: Dowling
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Veronica
authors.initials: V
authors.lastname: Caldeo
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Kelly
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland. Electronic address: sa.omahony@ucc.ie.
authors.forename: James A
authors.initials: JA
authors.lastname: O'Mahony
mesh_terms: D000818:Animals; D006801:Humans; D007223:Infant; D041943:Infant Formula / Q000737:chemistry*; D007782:Lactoglobulins / Q000737:chemistry*; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry*; D000067816:Whey Proteins / Q000737:chemistry*
chemical_list: D007782:Lactoglobulins; D008894:Milk Proteins; D000067816:Whey Proteins
keywords: Heat stability; Humanisation; Infant milk formula; Processing; Whey protein