Effect of repeat unit structure and molecular mass of lactic acid bacteria hetero-exopolysaccharides on binding to milk proteins. (1st December 2017)

• Record Type: Journal Article
• Authors: Birch, Johnny; Harðarson, Hörður Kári; Khan, Sanaullah; Van Calsteren, Marie-Rose; Ipsen, Richard; Garrigues, Christel; Almdal, Kristoffer; Hachem, Maher Abou; Svensson, Birte
• Is Part Of: Carbohydrate polymers. Volume 177(2017)
• Page Start: 406
• Page End: 414
• Publication Date: 2017-12-01
• Subjects: BCN β-casein -- BLG β-lactoglobulin -- DLS dynamic light scattering -- Gal galactose -- GalNAc N-acetylgalactosamine -- Glc glucose -- GlcNAc N-acetylglucosamine -- hBLG heat-treated BLG -- HePS hetero-exopolysaccharide -- HoPS homo-exopolysaccharide -- KCN κ-casein -- LAB lactic acid bacteria -- nBLG native BLG -- pI isoelectric point -- Pyr pyruvate -- Rha rhamnose -- SEC size-exclusion chromatography -- SNR signal-to-noise ratio -- SPR surface plasmon resonance; Hetero-exopolysaccharides (HePSs) -- β-lactoglobulin -- β- and κ-casein -- Binding parameters -- Surface plasmon resonance (SPR) -- Dynamic light scattering (DLS); Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2017.08.055
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Surface plasmon resonance was used to characterize HePS-milk protein interactions. Binding affinity depends on HePS size, repeat structure, pH and ionic strength. Heat-treatment of β-lactoglobulin dramatically increased HePS binding capacity. Abstract: Interactions of exopolysaccharides and proteins are of great importance in food science, but complicated to analyze and quantify at the molecular level. A surface plasmon resonance procedure was established to characterize binding of seven structure-determined, branched hetero-exopolysaccharides (HePSs) of 0.14–4.9 MDa from lactic acid bacteria to different milk proteins (β-casein, κ-casein, native and heat-treated β-lactoglobulin) at pH 4.0–5.0. Maximum binding capacity (RUmax ) and apparent affinity ( K A, app ) were HePS- and protein-dependent and varied for example 10- and 600-fold, respectively, in the complexation with native β-lactoglobulin at pH 4.0. Highest RUmax and K A, app were obtained with heat-treated β-lactoglobulin and β-casein, respectively. Overall, RUmax and K A, app decreased 6- and 20-fold, respectively, with increasing pH from 4.0 to 5.0. K A, app was influenced by ionic strength and temperature, indicating that polar interactions stabilize HePS–protein complexes. HePS size as well as oligosaccharide repeat structure, conferring chain flexibility and hydrogen bonding potential, influence the K A, app .