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Phosvitin-calcium aggregation and organization at the air-water interface
Corinne Belhomme1, Elisabeth David-Briand, Catherine Guérin-Dubiard
1UR1268 Biopolymères Interactions Assemblages, Equipe Interfaces et Systèmes Dispersés, INRA, F-44316 Nantes cedex 3, France.
Colloids and Surfaces. B, Biointerfaces
|December 11, 2007
Summary
Phosvitin, an egg yolk protein, can adsorb at air-water interfaces despite its negative charges. Calcium ions enhance phosvitin interfacial film compaction, influencing its structure and organization.
Area of Science:
- Food Science
- Protein Chemistry
- Surface Science
Background:
- Phosvitin, a major egg yolk phosphoprotein, possesses significant emulsifying properties.
- Its interfacial behavior, particularly at air-water interfaces, is not fully understood due to high charge density and aggregation tendencies.
Purpose of the Study:
- To investigate the impact of calcium ions on phosvitin interfacial film organization.
- To elucidate the adsorption behavior of phosvitin at the air-water interface.
Main Methods:
- Atomic Force Microscopy (AFM) was employed to study phosvitin interfacial films.
- Compression isotherms were used to analyze film properties with and without calcium ions in the subphase.
Main Results:
- Phosvitin successfully adsorbs at air-water interfaces, overcoming its high negative charge.
- A transition in the compression isotherm before 28 mN/m suggests structural changes in the interfacial film.
- Calcium ions induced greater compaction of the phosvitin interfacial film, even at low surface pressures.
Conclusions:
- Phosvitin adsorption at air-water interfaces is feasible, with calcium ions promoting film compaction.
- A model is proposed where phosvitin adsorbs via two hydrophobic ends in dilute conditions and one end in concentrated conditions (brush model).
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