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Influence of pH and Ionic Strength on Formation and Stability of Emulsions Containing Oil Droplets Coated by Beta-Lactoglobulin-Alginate Interfaces
Biomacromolecules (2006)
  • Thepkunya Harnsilawat
  • Rungnaphar Pongsawatmanit
  • D. Julian McClements, University of Massachusetts - Amherst
Abstract

Emulsions of 0.1 wt % corn oil-in-water containing oil droplets coated by β-lactoglobulin (0.009 wt % β-Lg, 5 mM phosphate buffer, pH 7.0) were prepared in the absence and presence of sodium alginate (0 or 0.004 wt %). The pH (3−7) and ionic strength (0−250 mM NaCl) of these emulsions were adjusted, and the particle charge, particle size, and creaming stability were measured. Alginate adsorbed to the β-Lg-coated droplets from pH 3 to 6, which was attributed to electrostatic attraction between the anionic polymer and cationic patches on the droplet surfaces. Droplets coated by β-Lg−alginate had better stability to flocculation than those coated by β-Lg alone, especially around the isoelectric point of the adsorbed proteins and at low ionic strengths (<100 mM>NaCl). At pH 5, alginate molecules desorbed from the droplet surfaces at high salt concentrations due to weakening of the electrostatic attraction.

Disciplines
Publication Date
May 3, 2006
Publisher Statement
DOI: 10.1021/bm050656q
Citation Information
Thepkunya Harnsilawat, Rungnaphar Pongsawatmanit and D. Julian McClements. "Influence of pH and Ionic Strength on Formation and Stability of Emulsions Containing Oil Droplets Coated by Beta-Lactoglobulin-Alginate Interfaces" Biomacromolecules Vol. 7 Iss. 6 (2006)
Available at: http://works.bepress.com/djulian_mcclements/113/