The redistribution of bulk aqueous phase phospholipids during thermal stressing of phospholipid-stabilized emulsions

The mechanism of the stabilization of triglyceride emulsions by phospholipids has been studied using an HPLC-FID method to determine phosphatidylcholine, lyso-phosphatidylcholine and phosphatidylethanolamine in the oil and aqueous phases of a model emulsion consisting of soybean oil 20 g, egg phospholipid 1.2 g, glycerol 2.25 g and water to 100 mL. It was shown that, on heat sterilization of the emulsions, the phospholipids rapidly relocate from the aqueous phase to the oil phase. It is suggested that the phospholipids concentrate in the oil/water meso phase, forming a cubic liquid crystalline phase, the bulk of which is converted to a lamellar phase on cooling, and that this organization of interfacial material accounts for the enhanced stability of phospholipid emulsions after heat sterilization.