The retention of organic volatiles in spray‐drying aqueous carbohydrate solutions

The effect of process conditions on retention of volatiles in spray‐drying was studied for aqueous solutions of malto‐dextrin to which acetone and alcohols were added as model aroma compounds. Volatile retention appeared to be independent of the relative volatility and was determined by the diffusion coefficient of the volatiles in the drying drops. The retention increased with increasing dissolved solids concentration in the feed. The optimum feed temperature for obtaining maximum retention increased with feed concentration. Highest retentions were obtained at the lowest air inlet temperature. At low feed concentrations retention became insensitive to air temperature. The effect of the various process variables on volatile retention can be explained by the selective diffusivity of water in aqueous solutions of organic solids at low water concentration