New insights about flocculation process in sodium caseinate-stabilized emulsions

Area of Science:

• Food science
• Colloid and surface science
• Materials science

Background:

• Emulsion stability is crucial in food and pharmaceutical industries.
• Sodium caseinate (NaCas) is a common emulsifier, but its self-assembly can lead to instability.
• Understanding NaCas behavior in emulsions is key to controlling product texture and shelf-life.

Purpose of the Study:

• To investigate the flocculation mechanism in NaCas-stabilized emulsions.
• To determine the influence of sucrose concentration on NaCas self-assembly and emulsion properties.
• To correlate microscopic structural changes with macroscopic emulsion behavior.

Main Methods:

• Formulation of oil-in-water emulsions with varying NaCas and sucrose concentrations.
• Emulsion preparation using ultraturrax and ultrasound homogenization.
• Characterization of droplet size distribution (SLS), stability (Turbiscan), and structure (CLSM, SAXS).

Main Results:

• Flocculation was primarily driven by NaCas self-assembly, linked to interfacial protein content.
• Sucrose addition significantly affected casein aggregation, influencing emulsion stability.
• SAXS analysis revealed structural changes in NaCas micelles correlating with observed emulsion behavior.

Conclusions:

• NaCas self-assembly is the primary cause of flocculation in these emulsions.
• Disaccharides like sucrose modulate casein aggregation through interactions with protein molecules and hydrophobic effects.
• Controlling NaCas structure is essential for managing emulsion physical properties.