Investigation and Optimization of Effective Parameters in Drying Yeast Process by Taguchi and RSM Statistical Design

Yeasts can be considered as the oldest industrial microorganisms used by humans. Yeast is an indispensable product for baking bread and is responsible for the desired fermentation of the dough and creating aroma and flavor in the bread.One of the effective factors in obtaining suitable yeast is providing the best drying conditions. Fluized bed drier is the most common methods for drying yeast. In this research, the effects of factors such as drying temperature, aeration and amount of surfactant that firstly were selected by Taguchi method as the most effective factors were investigated on the amount of CO2 released, moisture content and propagation of yeast alive by the RSM statistical design and eventually optimized. Based on the results, the best conditions for drying yeast by fluized bed at a temperature of about 39.8 °C, aeration of about 15600 m3 per hour, and surfactant 11.9 g/kg of yeast were determined by the Minitab software. In this condition was found to have the highest viability (78.8%), minimum moisture content (37.5%) and the highest CO2 production (1390 cc/2h) for yeast.