Microencapsulation of Lacticaseibacillus rhamnosus GG and L. plantarum 299 V by reverse spherification: a promising method to improve the survival of probiotics

This research reports the first application of the reverse spherification (RVS) method for encapsulation of two probiotics (Lacticaseibacillus rhamnosus GG and L. plantarum 299 V) compared to the basic spherification (BS). These probiotics were encapsulated in different solutions encompassing various contents of alginate, gelatin, and gellan gum. The RVS bead diameters was about 1.5 times bigger and hardness was 70%-80% lower than BS samples. As determined by Raman spectral mapping, the RVS beads had two calcium alginate walls but the BS beads had only one. The inner wall of the RVS beads was more than three times thicker than outer wall. The encapsulation yields of gelatin/gellan gum and gelatin beads prepared by both methods were >1.5% alginate beads. All the RVS-prepared beads were resistant to stomach acid and showed no significant reduction in the intestine. Furthermore, the incorporation of gelatin and gellan gum into alginate led to higher cell protection. For 1.5% alginate beads, <67% survival was achieved after acid exposure but in others, >77% survival was observed; RVS beads were about 1 log above than BS ones. The proposed novel microencapsulation method efficiently increased the viability of probiotic bacteria compared to the conventional approaches.