Encapsulation of garlic extract using complex coacervation with whey protein isolate and chitosan as wall materials followed by spray drying

This study aimed to encapsulate garlic aqueous extract by complex coacervation with whey protein isolate (WPI) and chitosan (CH) with three degrees of deacetylation (DD; 83%, 94% and 96%), followed by spray drying. Preliminary assays of coacervation indicated that optimum complex coacervation occurred at a CH/WPI mass ratio of 0.2: 1 (w/w). The coacervates showed zeta potential values toward zero, confirming that coacervation occurred through electrostatic interactions between positive and negative charges of CH and WPI, respectively. The coacervates exhibited the shear-thinning behavior of pseudoplastic fluids. The magnitude of elastic modulus higher than loss modulus revealed the formation of an elastic gel structure. Creep-recovery tests showed that the coacervate with a CH DD of 96% had lesser compliance due to its more compact and stronger internal structure. For encapsulated garlic extract powders, phenolic compound retention efficiency ranged from 51% to 61%. FTIR confirmed the complexation between CH and WPI, and similar band profiles found among garlic extract and microparticles powders indicate that garlic compounds were intact and encapsulated. Scanning electron microscopy images showed all microparticles with a spherical shape and no evidence of cracking or fissures on the surface.