Effect of different coating materials on the biological characteristics and stability of microencapsulated Lactobacillus acidophilus

Abstract

The effect of different coating materials on the biological characteristics and stability of microencapsulated Lactobacillus acidophilus was investigated. Results indicated that the surface and microstructure of microcapsules were significantly affected by the type of coating material. A complex carrier could provide protection for L. acidophilus cells against simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Cell survivals give higher counts with 2.1 and 3.72 logarithmic cycle reduction found in microencapsulated L. acidophilus with complex wall materials and free cells after exposure to SIF for 180 min, respectively. Furthermore, at the high temperatures investigated, a higher cell survival rate in microcapsules embedded with complex materials was found than for free cells and those with other materials. Cell counts were reduced to 8.16, 7.17, and 6.42 log CFU mL⁻¹ and 5.86, 4.29, and 2.32 log CFU mL⁻¹ for microcapsules with complex materials and free cells treated at 50, 60 or 70 °C for 20 min, respectively. Stability was also improved compared to free cells at refrigerated temperatures. For the cells that were released from microcapsules, the counts increased with a prolonged incubation time. Moreover, the survival rate of cells with microencapsulation was better than that of free cells at high concentrations of bile salt. Results showed that for improving protection against deleterious factors, complex materials might be a better choice for the preparation of microcapsules.