Effect of oil droplet size on the oxidative stability of spray-dried flaxseed oil powders

The effect of the size of oil droplets on the oxidative stability of flaxseed oil in spray-dried powders was investigated. Maltodextrin with a dextrose equivalent of 25 was used as a wall material, and sodium caseinate and transglutaminase-polymerized sodium caseinate were used as emulsifiers. The oxidative stability of flaxseed oil encapsulated in the spray-dried powders was evaluated using lipid oxidation and conductometric determination tests at 105 degrees C. The powders containing larger oil droplets exhibited higher surface oil content after spray drying, and higher peroxide value and conductivity after storage at 105 degrees C. Removal of the surface oil from the powders by washing with hexane significantly decreased the conductivity. The results indicated that the surface oil of the spray-dried flaxseed oil powders affected the oxidation stability.