Measured effect of encapsulation and freeze-drying on the structural organisation of β-lactoglobulin–pectin complex coacervates with curcumin and folic acid

Encapsulation systems based on protein-polysaccharide complex coacervates have important applications in the food industry. They deliver bioactives and impart desired structural and textural properties. In this study, complex coacervates composed of β-Lactoglobulin (βLg) and pectin at a molar ratio of 20:1, pH 4, and ionic strength of 20 mM encapsulated two bioactive molecules, curcumin and folic acid. The bioactives were bound to βLg A (1:1 M ratio) prior to forming the complex coacervates with pectin. The complex coacervates were freeze-dried to show the impact of this common preparation method for sensitive bioactives on the physicochemical properties and structure of the complex coacervates. Small and ultra-small angle neutron scattering give the complex coacervate structure on multi-length scales ranging from the primary particles of 100 nm to the fractal network of 10 μm. Our work shows that the hierarchical structures formed by the complex coacervates are preserved both on encapsulation and freeze-drying.