Microencapsulation of Lactobacillus acidophilus LA-5 and Bifidobacterium animalis subsp. lactis BB-12 in alginate and pectin, and the effects on bacterial acid and bile resistance

This study aimed to encapsulate Lactobacillus acidophilus LA-5 (LA-5) and Bifidobacterium animalis subsp. lactis BB-12 (BB-12) in alginate and pectin, and to determine the effects of acid and bile resistance. The emulsion method was used; different gel and CaCl2 concentrations and stirring rate were studied comparatively for the characterization of microcapsules. Alginate microcapsules were smaller and exhibited agglomeration behavior, while pectin microcapsules were fairly homogeneous and had a smooth shape. Encapsulation efficiency (EE) percentages of the bacteria cells encapsulated with alginate and pectin varied within a very narrow range of 83 to 85%. The size of microcapsules increased as the gel concentration increased, and decreased as the CaCl2 concentration and stirring rate increased. Microencapsulated cells had more acid and bile resistance than free cells. No significant difference was found between alginate and pectin microcapsules of the two strains in terms of acid and bile resistance. The probiotic strains encapsulated with pectin and alginate maintained higher levels of viability under acid conditions at pH 2 and 3 than at pH 1 after 24 hours of incubation.