Preparation of alginate beads containing Lactobacillus acidophilus using AlCl3 as a cross linker

摘要

Beads of alginate-containing probiotic bacteria of Lactobacillus acidophilus were prepared by an extrusion method using AlCl3 as a cross linker and characterized in terms of size, morphology and encapsulation efficiency. The optimum formulation was selected, and the viability of encapsulated L. acidophilus after acid treatment (pH = 2, duration = 2 hours) was investigated. Spherical beads ranging from 1.45 mm to 1.65 mm in size were achieved. The shape and size of the optimum beads (F9) prepared using 3% alginate and 3.5% AlCl3 as a cross linker were not significantly different than those of beads prepared using 3% alginate and 3.5% CaCl2 as a cross linker (F10). However, substitution of AlCl3 for CaCl2 significantly increased the acid viability of the encapsulated L. acidophilus in F9. The increased acid viability is probably due to the greater crosslinking within the structure of the produced coat, which is permitted by the extra linkage sites in AlCl3. Additional experiments to evaluate the physicochemical and morphological structure of the prepared coat should be performed to explain the exact mechanism of protection.