Sonochemical fabrication and characterization of β-Lactoglobulin-Galactooligosaccharide conjugates: Enhancement of calcium absorption

Solid-in-oil-in-water (S/O/W) emulsions containing calcium carbonate (CaCO 3 ) are a potential new type of calcium-fortified emulsion system. This study developed ultrasonication-pretreated β-lactoglobulin (ULG)-galactooligosaccharide (GOS) conjugates using a novel combined method involving ultrasonication and Maillard reaction. This synergistic approach significantly increased the grafting degree and induced structural modifications of protein. The ULG-GOS conjugates exhibited superior emulsifying properties and interfacial stabilization capacity through exposed hydrophobic domains and strengthened electrostatic repulsion. When applied as stabilizers for S/O/W emulsions, ULG-GOS conjugates form a homogeneous system with significantly improved environmental stability. Notably, in vitro digestion studies revealed a 2-fold increase in calcium bioaccessibility (58.77 ± 1.75 %) of ULG-GOS stabilized system compared to native LG-stabilized systems. This study underscored the critical role of ultrasonication in enhancing the functionality of LG-GOS conjugates, which were essential to nutritional formulations designed to facilitate calcium absorption.