Encapsulation of probiotic bacteria Lactobacillus acidophilus by direct compression

The objective of the work is to evaluate the potential use of compression coating as an alternative method for the encapsulation of probiotic bacteria Lactobacillus acidophilus to improve their storage stability. Microbial cell containing powders were first compressed into a pellet, which was then encapsulated with a coating material of a combination of sodium alginate and hydroxypropyl cellulose by further compression. The effect of compression pressure on cell viability was studied. Results showed that compression of the microbial cell containing powders at pressures up to 90 MPa caused little loss of viability of the bacteria. Beyond 90 MPa, the cell viability decreased almost linearly with the compression pressure. Further compression to form a coating did not cause significant reduction in the cell viability. The stability of the encapsulated bacteria using the compression pressures up to 60 MPa was approximately 10 times higher than free cell containing powders and cell pellets after 30 days storage at 25degreesC.