Emulsions Stabilized by Gum Arabic: How Diversity and Interfacial Networking Lead to Metastability

Area of Science:

• Food Science
• Colloid and Surface Chemistry
• Biomaterials Science

Background:

• Gum arabic (E414) is a natural hydrocolloid widely used as a food additive.
• It provides metastability to oil-in-water emulsions, even under dilution.
• The precise mechanism of its stabilizing properties requires further investigation.

Purpose of the Study:

• To elucidate the mechanism behind gum arabic's emulsion stabilizing properties.
• To investigate the role of amphiphilic species' interfacial packing and aggregation.
• To understand the structure of the adsorbed layer formed by gum arabic.

Main Methods:

• Scattering analyses
• Chromatographic analyses
• Development of a harvesting method for adsorbed species

Main Results:

• Increasing interfacial packing of amphiphilic species leads to irreversible aggregation driven by hydrophobic interactions between protein chains.
• Size diversity of amphiphilic species influences aggregation, with smaller species aggregating first.
• Gum arabic forms a stable interfacial shell composed of a 2D protein network cross-linked by hydrophobic interactions, covalently linked to polysaccharides.

Conclusions:

• The adsorbed gum arabic forms a robust shell anchored by a protein network and hydrated polysaccharides, providing steric repulsion.
• This structure enhances emulsion metastability and resistance to mechanical stress and environmental changes.
• Findings enable more rational applications of gum arabic in emulsion stabilization.