Adsorption of beta-casein to hydrophilic silica surfaces. Effect of pH and electrolyte

Research output: Contribution to journalArticle

Abstract

Adsorption of beta-casein to hydrophilic silica surfaces has been studied as an effect of pH and electrolyte, in the latter concentration, valency, and specificity (calcium or magnesium) have been considered. The used protein concentration has been an order of magnitude below the critical aggregation concentration, which implies that the protein is in monomeric form. By varying the salt concentration, the pH, and the concentration of divalent ions as calcium and magnesium, it is clearly shown that electrostatic interactions are of importance for adsorption of beta-casein to silica surfaces and tunes the adsorbed amount and saturation of the surface. Our results show that there is counterbalance between: (i) electrostatic repulsion between the surface and the protein, (ii) electrostatic attraction between positively charged amino acids in the protein and the surface, and (iii) electrostatic repulsion and excluded volumes between adsorbed proteins at the surface, and that the positively charged amino acids serve as anchoring points. (C) 2013 Elsevier Ltd. All rights reserved.

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Authors
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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Food Science

Keywords

  • Milk protein, Casein, Surfaces, Hydrophilic silica, Adsorption
Original languageEnglish
Pages (from-to)332-338
JournalFood Hydrocolloids
Volume36
Publication statusPublished - 2014
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Theoretical Chemistry (S) (011001039)