Enhancing viability of Lactobacillus plantarum encapsulated by alginate-gelatin hydrogel beads during gastrointestinal digestion, storage and in the mimic beverage systems

Abstract

To improve the viability of Lactobacillus plantarum (P) during digestion and storage, the probiotics were encapsulated by alginate (ALG) and alginate-gelatin (ALG-GE) hydrogels beads. ALG-P-GE showed much better physicochemical properties than ALG-P. The scanning electron microscopy (SEM) results validated the incorporation of bacterial cells into the beads. ALG-P-GE exhibited good encapsulation efficiency of 97.7 %, and the storage and thermal stability of probiotic were increased by 15 % and 8 %, respectively, when comparing with ALG-P. ALG-P-GE beads could protect the probiotics from inactivation in simulated gastric fluid and then release it in simulated intestinal fluid. The protective mechanism of ALG-GE for probiotics was further studied by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and found that ALG and GE can form gel network through hydrogen bonding and electrostatic interactions. In the mimic beverage systems, ALG-P-GE beads could protect the encapsulated probiotics and increase its viability. The storage, thermal, and digestion stability of encapsulated probiotic were significantly increased and showed high viability in the mimic beverage systems. ALG-P-GE beads have great potential for the protection and delivery of probiotics in food systems.

Keywords: Hydrogels; In vitro gastrointestinal digestion; Probiotic encapsulation.