Effect of Lipid Type on the Retention of Methyl Ketones During Spray Drying of Milk Systems

The retention of n-methyl ketones during spray drying of skim milk systems containing different types of fats was examined. Methyl ketones (C₄ to C₁₁) were blended into butter, coconut, hydrogenated coconut, soybean, or hydrogenated soybean oil and then homogenized into condensed skim milk yielding a model system 25% fat (dry basis) and 30% total solids. The model systems were spray dried and then analyzed for ketone retention by making 2,4-dinitrophenylhydrazone derivatives followed by high-pressure-liquid chromatography. Ketone retention increased with carbon chain length up to 2-octanone and then was constant. There were significant differences in ketone retention between fats with coconut providing the best retention and soybean oil the poorest.