Physical and chemical stability under environmental stress of microemulsions formulated with fish oil

Enrichment of food and beverages with bioactive lipids is an important initiative to improve consumer´s health. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids present in fish oil have been reported as those with the greatest bioactivity. Emulsions are an interesting alternative to incorporate functional oil; however, there are few studies on food microemulsions as a way to include this kind of compounds. The present work is intended to deepen the analysis of the Kolliphor RH40 emulsifier with potential application in food microemulsions, characterizing its micellar size and thermo-rheological properties, as well as analyzing the effect of environmental stress on physical and oxidative stability of a microemulsion containing fish oil. No significant changes in droplets size (<15 nm) or in their distribution was observed in a wide range of pH (3?9), ionic strength (0.1?10% CaCl2), centrifuging and different thermal treatments. During freezing, a slight increase in size (