The encapsulation of Lactobacillus casei probiotic bacteria based on sodium alginate and chitosan

Chitosan is a polysaccharide that can be used as a material in the encapsulation of probiotic bacteria. The process of bacterial encapsulation with chitosan polymers was carried out to protect the Lactobacillus casei bacteria which cannot last long in very acidic environments so that they can survive when exposed to gastric acid conditions and can live in the intestine. The purpose of this study was to determine the effect of extrusion voltage on the survivability of L. casei bacteria in the encapsulation process. The encapsulation process in this study was carried out by the extrusion-emulsion method using a sodium alginate of 1 % (w/v) and chitosan of 0.2 % (w/v) and voltage variations of 0 kV, 10 kV and 20 kV. The resulting beads were immersed in a simulated gastric fluid (SGF) (NaCl 0.2 %; HCl 0.5 M with a pH of 1.5) for 0, 60 and 120 minutes at 37 °C. The number of L. casei cells before encapsulation was 1 - 10⁹ cfu/mL. After encapsulation with voltage variations of 0 kV, 10 kV and 20 kV, the viability of probiotics were 2.6 - 10⁸ cfu/g, 1-10⁷ cfu/g, and 1 - 10³ cfu/g, respectively. After testing the beads in SGF, the obtained results indicated that viability of L.casei in the sodium alginate - chitosan beads with an extrusion voltage of 0 kV were 20,300 cfu/g, 10 kV were 30 cfu/g and 20 kV were 0 cfu/g. The results of these studies indicated that survivability of L. casei in the sodium alginate - chitosan beads with a voltage of 0 kV indicates the highest survivability level of 51.19 % of the number of cells encapsulated after incubation in SGF and the higher voltage can kill more L. casei.