Gellan gum electrohydrodynamic microencapsulation of probiotics for intestine-targeted delivery

Microencapsulation is a promising strategy to improve time-stability, viability and targeted delivery of probiotics, thus enhancing their beneficial roles in the intestine. However, areas of improvement persist, including optimal viability protection during storage and gastrointestinal (GI) transit, control over encapsulation and targeted release. Due to pH-responsiveness, gellan gum (GG) could be ideal to face some of these criticalities. In this study, we set-up a robust electrohydrodynamic (EHD) microdripping process to produce GG microparticles (GGMs) encapsulating Limolactobacillus fermentum. By varying GG concentration, flow rate and applied voltage, the optimized EHD parameters led to highly monodisperse microbeads with controlled morphology. Successful encapsulation of L. fermentum in GGMs was obtained at concentrations of 10⁶ CFU/mL and 10⁹ CFU/mL, leading to 300 ± 40 μm and 450 ± 100 μm particle sizes, with encapsulation efficiency of 94 ± 6 % and 99 ± 1 %, respectively. GGMs demonstrated post-encapsulation probiotic viability with lactic acid production. Freeze-dried formulations were lasting under storage until 3 months and resulted stable under GI-simulated conditions. Their bioactive properties were demonstrated by antimicrobial efficacy against Escherichia coli and enhanced defensin expression in Caco-2 intestinal cells. Overall, EHD microdripping was a versatile and robust platform useful in functional foods and gut microbiome engineering.