Flow and fluidization behaviour of yeasts in gas/solid fermentation and drying.

Beside its use in chemical and pharmaceutical industry fluidized bed technology is applied as well in food processing or for gas/solid fermentation with means of pellitised yeast. As for fermentation high water activity of the microorganism resp. a water content of about 70 wt.-% has to be maintained, the fluidization and flow behaviour of the yeast pellets has to be looked upon as a critical parameter for the application of fluidized bed technology here. In this paper the fluidization and flow behaviour of active baker's yeast with and without conditioner was examined as a function of moisture content. Comparing the characteristic values of minimum fluidization and flowability showed a significant interrelation, that can be explained by interparticle forces according to moisture content.