[Conditions of yeast freeze-drying studied by methods of planning experiments]

The effect of seven factors on survival and residual humidity of yeast suspensions was studied during freeze-drying of Saccharomyces cerevisiae using methods of mathematical planning of the experiment. A multifactor experiment of the type 2(7-4) was realized, according to which all factors were varied at two levels. Adequate equations for regression were obtained to describe the process in the temperature zone above the eutectic point (from -10 to -15 degrees C) and below it (from -30 to -40 degrees C). The effect of the studied factors was found to depend on temperature of freeze-drying. The equations were used for optimizing freeze-drying by the method of "sharp ascending".