Microencapsulation of Lactobacillus paracasei by spray freeze drying

This study evaluates the implementation of a new process: spray freeze drying (SFD), to produce dry micro-capsules of Lactobacillus paracasei with high viability. The study concentrated on determining the survival of the cells, encapsulated in a matrix of maltodextrin and trehalose. SFD was compared with the conventional bulk freeze drying (BFD). Overall it was shown that SFD is a successful method to generate dry micro-capsules of probiotic cells with high viability (>60%). The spraying stage did not affect the viability of the bacteria. In the freezing stage, high osmotic pressures originated by elevated trehalose concentrations, helped preserving the cells viability. It was also found that the lower the maltodextrin molecular weight, the larger the beads volume and solids concentration, the higher is the bacteria survival during the freezing and drying stages. In the drying stage, trehalose concentration was also the critical factor that increased final probiotic viability.