Co-encapsulation of probiotic bacteria and fructooligosaccharides in basil seed gum-stabilized double emulsion gels: Probiotic viability and physicochemical properties

Double emulsions (DEs) present many potential applications for encapsulating and protecting probiotics. However, their high instability limit their real applications. To improve the prolonged stability of DEs, Lacticaseibacillus rhamnosus and Lactobacillus gasseri were separately co-encapsulated together in the presence of fructooligosaccharides (FOSs) and basil seed gum (BSG) within the internal (W1) and external (W2) aqueous phases of double emulsion gels (DEGs; W1-sol/O/W2-gel). Physical properties of DEGs, and viability of probiotics during heat processing, gastrointestinal digestion and storage were evaluated. Appropriate physical stability was observed during storage for 28 d at 4 ± 2 °C. The FOSs and microorganism type showed not effect on the droplet size (10.63 to 10.47 µm). Turbidimetry, physical stability, and morphological studies revealed the formation of aggregated droplets after 3 weeks. All DEGs presented high (>90 %) encapsulation efficiency. The viability of microencapsulated probiotics over time (14.89–14.08 %) and against simulated gastrointestinal conditions was higher than that of free cells. The encapsulation of bacteria in W1 in the presence of FOSs led to a significant improvement of viability against heat (only 1.35 % to 6.83 % reduction at 72 °C). L. gasseri showed a higher stability against environmental conditions. Finally, BSG-stabilized DEGs can be considered for increasing the viability of probiotic in functional foods.