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Research article2012Peer reviewedOpen access

Binding Interactions Between alpha-glucans from Lactobacillus reuteri and Milk Proteins Characterised by Surface Plasmon Resonance

Diemer, Silja K.; Svensson, Birte; Nygren-Babol, Linnea; Cockburn, Darrell; Grijpstra, Pieter; Dijkhuizen, Lubbert; Falkenberg, Ditte M.; Garrigues, Christel; Ipsen, Richard H.


Interactions between milk proteins and alpha-glucans at pH 4.0-5.5 were investigated by use of surface plasmon resonance. The alpha-glucans were synthesised with glucansucrase enzymes from Lactobacillus reuteri strains ATCC-55730, 180, ML1 and 121. Variations in the molecular characteristics of the alpha-glucans, such as molecular weight, linkage type and degree of branching, influenced the interactions with native and denatured beta-lactoglobulin and kappa-casein. The highest overall binding levels were reached with alpha-(1,4) compared to alpha-(1,3) linked glucans. Glucans with many alpha-(1,6) linkages demonstrated the highest binding levels to kappa-casein, whereas the interaction with native beta-lactoglobulin was suppressed by alpha-(1,6) linkages. Glucans with a higher degree of branching generally displayed lower protein binding levels whereas a higher molecular weight resulted in increased binding to kappa-casein. The interactions with kappa-casein were not pH dependent, whereas binding to denatured beta-lactoglobulin was highest at pH 4.0 and binding to native beta-lactoglobulin was optimal at pH 4.5-5.0. This study shows that molecular weight, linkage type and degree of branching of alpha-glucans highly influence the binding interactions with milk proteins.


alpha-glucan; Homopolysaccharides; beta-lactoglobulin; kappa-casein; Lactobacillus reuteri; Surface plasmon resonance

Published in

Food Biophysics
2012, Volume: 7, number: 3, pages: 220-226
Publisher: SPRINGER

    UKÄ Subject classification

    Food Engineering

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