Partitioning of printing ink solvents between cookie ingredients and air before and after baking

Partitioning (Kp) of printing ink solvents was studied in individual ingredients of cookies with different fat and water content. Structure and moisture changes in ingredients during baking at 260 degrees C for 10 min caused some changes of migration behavior. Kp of toluene and hexane in high fat samples generally remained unchanged but Kp of polar solvents ethyl acetate, isopropanol, and methyl ethyl ketone decreased with decreases in water. Increases in crystallinity diminished Kp values. The order of affinity could be predicted by Hildebrand solubility parameter (delta) value differences between ingredients and non-polar solvents, but predictions for polar solvents were influenced by changes in water content.