Release Properties and Stability of Double W sub(1)/O/W sub(2) Emulsions Containing Pumpkin Seed Oil

The double Water-in-Oil-in-Water emulsions containing a mixture of pumpkin seed and sunflower oil were prepared with polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier and different hydrophilic emulsifiers, whereby Tween 20 showed the best stabilization effects. Two different stabilization methodologies of the Water-in-Oil emulsions, (1) stabilization against molecular diffusion degradation (Oswald ripening) by electrolyte (NaCl) addition and (2) gelling of internal water droplets using alginate to form gel phase were employed. Emulsion with co-stabilizer was more stable during storage and heating/freezing treatment than Gel-in-Oil emulsions. Glucose was introduced as a thickening agent in the external water phase. The regulation of the osmotic pressures between the water compartments by glucose addition to the external water phase can be employed to modulate the release behavior of encapsulated material and improve the droplet stability. Also, simple correlation was proposed to predict the release fraction of the salt toward the external water phase. Practical Applications Due to their low stability the double emulsions are rarely able to overcome the research phase and to this day have not been converted into commercial products. However, as carriers for the preservation of sensitive components from the environmental exposure destruction, emulsions can provide long term retention of encapsulated material and allow the production of low calorie food products. The incorporation of pumpkin seed oil in the double emulsions due to a multitude of valuable components in its composition contributes to nutritional value of products, making in this way designed emulsions a good base for the preparation of the functional food. Second, encapsulation of salt in double emulsions, except the practical application for the preparation of salted creams, enhances the stability of the emulsions and gives the possibility of tracking the release of hydrophilic material from internal water phase.