Tuning alginate β-lactoglobulin complex coacervation by modulating pH and temperature

Area of Science:

• Food Science and Technology
• Biochemistry
• Materials Science

Background:

• Green chemistry trends favor natural biomolecules in food and encapsulation.
• Complex coacervation between anionic polysaccharides (alginate) and proteins (β-Lg) is a key green technology.
• Previous studies focused on macromolecular interactions, overlooking molecular details.

Purpose of the Study:

• To investigate the molecular mechanisms of alginate-β-Lg complex coacervation.
• To explore the influence of pH and temperature on coacervation properties.
• To provide insights for optimizing microencapsulation and drug delivery systems.

Main Methods:

• Detailed biophysical and chemical characterization of coacervation and coacervate particles.
• Isothermal titration calorimetry (ITC) to quantify proton exchange.
• Investigation of pH and temperature effects on coacervation behavior.

Main Results:

• Carboxylate resonance stabilization in alginate influences proton exchange during coacervation.
• Quantified proton release (4 per β-Lg) at pH 2.65 and uptake (2 per β-Lg) at pH 4.00.
• A secondary, temperature-induced (65 °C) coacervation step was observed, forming large, entropy-driven assemblies.

Conclusions:

• Alginate-β-Lg coacervation is tunable via pH and temperature, offering control over particle formation.
• Understanding molecular interactions and proton exchange is crucial for optimizing coacervation processes.
• Findings advance the application of complex coacervation in microencapsulation and drug delivery.