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

Silja K. Diemer*, Birte Svensson, Linnea N. Babol, Darrell Cockburn, Pieter Grijpstra, Lubbert Dijkhuizen, Ditte M. Folkenberg, Christel Garrigues, Richard H. Ipsen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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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.

Original languageEnglish
Pages (from-to)220-226
Number of pages7
JournalFood Biophysics
Volume7
Issue number3
DOIs
Publication statusPublished - Sept-2012

Keywords

  • alpha-glucan
  • Homopolysaccharides
  • beta-lactoglobulin
  • kappa-casein
  • Lactobacillus reuteri
  • Surface plasmon resonance
  • LACTIC-ACID BACTERIA
  • LACTOCOCCUS-LACTIS
  • CASEIN MICELLES
  • STRUCTURAL-ANALYSIS
  • BETA-LACTOGLOBULIN
  • SUBSP CREMORIS
  • EXOPOLYSACCHARIDES
  • CULTURES
  • STRAINS
  • REUTERANSUCRASE

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