Multilayer co-encapsulation of probiotics and γ-amino butyric acid (GABA) using ultrasound for functional food applications

Abstract

Double emulsion (W1/O/W2) microcapsules containing probiotic lactic acid bacteria (LAB) and bioactive γ-aminobutyric acid (GABA) were prepared by two-step ultrasonication using dextran and whey protein as encapsulating materials. The formulation and ultrasound parameters were refined to optimise the size of the W1/O droplets and outer microcapsules (5–15 μm) for encapsulation of both LAB and GABA. Optical, fluorescence and SEM microscopy revealed the morphology of the microcapsules and confirmed the presence of encapsulated LAB. Ultrasound treatment for up to 200 s had no significant effect on bacteria viability (>10 CFU/mL), while GABA helped stabilise the primary (W1/O) emulsion and was u..