Comparison of different methods for microencapsulation of probiotics

At the Department of Food Technology at Fulda University of Applied Sciences different methods for microencapsulation of Lactobacillus reuteri DSM 20016 were investigated. The aim of these studies was to develop a process to stabilize the probiotic bacteria for storage and to prevent them from the gastric conditions, to ensure that a satisfactory amount of the probiotics could reach their target location, the human intestine. Drying processes like spray drying and freeze drying were tested as well as fluidized bed granulation with optional Wurster coating using different auxiliary materials. As encapsulation material maltodextrine, sweet whey powder or gummi arabicum were used. The coating experiments were performed with an aqueous shellac solution. In the performed studies the fluidized bed bottom spray granulation with an additional Wurster coating turned out to be an encouraging procedure to keep the probiotics in a stable form resistant against gastric conditions. The survival rate in the simulated gastro-intestinal passage could be increased up to the sevenfold amount of the untreated bacteria.

Fluidization control in the wurster coating process

Paniculate coating process in a fluidized bed involves different sub processes including particle wetting, spreading and also consolidation or drying of the coating applied. These sub processes are done simultaneously to particle fluidization and motion. All the parameters of fluidization are known to affect the coating quality. That is why the motion of particles in the Wurster coating process has been observed and described step by step. These observations have achieved a general understanding of phenomena which take place inside the bed during fluidization and have allowed the development of an easy method for optimizing all the parameters affecting this operation.