Abstract

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.

Keywords

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

SLU Authors

• Nygren Babol, Linnea

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Food Engineering


Publication identifier

DOI: https://doi.org/10.1007/s11483-012-9260-5

Permanent link to this page (URI)

https://res.slu.se/id/publ/45157