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    Stabilising effect of α-lactalbumin on concentrated Infant Milk Formula emulsions heat treated pre- or post- homogenisation


    Buggy, Aoife and McManus, Jennifer and Brodkorb, André and McCarthy, Noel and Fenelon, Mark (2017) Stabilising effect of α-lactalbumin on concentrated Infant Milk Formula emulsions heat treated pre- or post- homogenisation. Dairy Science & Technology, 96 (6). pp. 845-859. ISSN 1958-5594

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    Abstract

    Protein type and/or heat treatment pre- or post-homogenisation can affect the physical stability of infant formulations during manufacture. Previous research has described the use of α-lactalbumin addition in infant formulae, but has not demonstrated the effect of heating pre- or post-emulsion formulation during processing. The objective of this study was to evaluate the effect of both of these parameters. Three batches of model 1st-stage infant formula containing differing whey protein ratios (60:40 whey: casein with α-lactalbumin content 12, 30 or 48% of total protein) were prepared. Each batch was split; one half receiving heat treatment pre-homogenisation and the second half homogenised and then heat treated. Emulsion stability was determined by size exclusion chromatography, SDS-PAGE, particle size and viscosity measurements. There was a significant (P < 0.05) reduction in the formation of large soluble aggregates upon increasing α-lac concentration in emulsions heat treated either before or after homogenisation. Heat treatment of formulations post-homogenisation resulted in a higher (P < 0.05) D.v09 within the particle size distribution; increasing α-lactalbumin concentration to 30 or 48% significantly (P < 0.05) reduced the D.v09 within the particle size distribution in these emulsions. The viscosity of concentrates (55 % total solids) containing the 12% α-lactalbumin, heat treated post-homogenisation, was significantly greater (P < 0.05) than the equivalent emulsion heat treated pre-homogenisation; increasing the α-lactalbumin concentration to 30 or 48% significantly (P < 0.05) reduced viscosity. When the α-lactalbumin content was increased to 48% as a percentage of the total protein, heating before or after emulsion formation had no effect on concentrate viscosity. The findings demonstrate the importance of thermal denaturation/aggregation of whey proteins (and in particular, the ratio of α-lactalbumin to β-lactoglobulin) prior to homogenisation of infant formula emulsions.

    Item Type: Article
    Additional Information: This is the author’s version of a work that was accepted for publication in Dairy Science & Technology. Changes may have been made to this work since it was submitted for publication. The final publication is available at link.springer.com and may be cited as Dairy Science & Technology, 2017, 96(6), 845-859. doi: 10.1007/s13594-016-0306-1
    Keywords: α-Lactalbumin; β-Lactoglobulin; Infant milk formula; Emulsion stability;
    Academic Unit: Faculty of Science and Engineering > Chemistry
    Item ID: 10775
    Identification Number: https://doi.org/10.1007/s13594-016-0306-1
    Depositing User: Jennifer McManus
    Date Deposited: 08 May 2019 14:44
    Journal or Publication Title: Dairy Science & Technology
    Publisher: Springer
    Refereed: Yes
    Funders: Department of Agriculture, Food and the Marine, Teagasc Walsh Fellowship Programme
    URI:

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