Retention of volatiles in spray drying and freeze-drying

During spray drying with inlet air temperature 170-190 degrees C, outlet ai r temperature 70-100 degrees C, and solids concentration in the feed 20-40% w/w, all three variables influenced retention of benzaldehyde, D-limonene and pentanol in maltodextrin (DE 11-14) as model volatile carrier. In paral lel experiments in freeze-drying volatile retention was higher. The glass transition temperature of maltodextrin powder, conditioned to dif ferent water activities, measured by differential scanning calorimetry decr eased in a near linear relationship as water activity increased in the rang e 0.11 to 0.87.