Microencapsulation of Lactobacillus acidophilus CGMCC1.2686: Correlation Between Bacteria Survivability and Physical Properties of Microcapsules

Correlation between lactic acid bacteria (LAB) survivability and physical properties of microcapsules is critical to revealing the protecting mechanism of microcapsules for LAB. In this paper, five formulae of microcapsules with increasing mechanical strength were chosen to encapsulate Lactobacillus acidophilus CGMCC1.2686 using the method of emulsification/internal gelation. Morphological and size characteristics showed that particle diameter of the five LAB microcapsules ranged from 263.4 to 404.6 mu m, with a span factor from 0.87 to 1.12. The increased mechanical strength of the microcapsules was accompanied with increased viscoelasticity and structural compactness as observed by scanning electron microscopy. Most of the microspheres shrinked in simulated gastric juice (SGJ), whilst swelling in bile salts solution (BS). Regression analysis showed that cell viability in SGJ was positively correlated with the mechanical strength of microcapsules. However, increasing mechanical strength did not significantly improve cell survival in BS.