(191d) Process Development for the Spray Drying of Milk Protein Stabilized Emulsions with High Oil Content

Spray drying is one of the most cost effective and scalable method for ingredient microencapsulation. Lipophilic ingredients, such as fish oil, beta carotene, and hydrophobic minerals and vitamins, can be encapsulated with carbohydrates as wall materials. We present a process development study on the spray drying of milk protein stabilized emulsions with high oil content. First, we found that pre-evaporation of raw milk not only reduces energy cost and equipment space occupation, but also improves the stability of pre-spray emulsions and thus reduces fat loss in this process. Second, adding carbohydrates provides a stronger barrier that reduces the portion of surface extractable fat, a main cause of oil leakage during long-term storage particularly for high oil content powder. The hydrophilicity of carbohydrates also improves powder dispersibility through dissolution-enhanced wetting. We found that carbohydrates with smaller molecular weights perform better at reducing surface extractable fat and improving surface wettability. This product will serve as the main ingredient of a powdered ready-to-use therapeutic food to treat severe malnutrition in India.