Changes in the surface tension and viscosity of fish oil nanoemulsions developed by sonication during storage

Adequate consumption of ω3 essential fatty acids (EFAs) has a positive impact on human health. EFAsenriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions developed by sonication method were subjected to various analyses as a function of hydrophilic lipophilic balance (HLB) and surfactant to oil ratio (SOR). Analyses were performed upon production and during 1month storage at two temperatures (4 and 25 ˚C) in the presence (100 ppm) or absence of αtocopherol. Increasing in HLB and SOR decreased the particle size and surface tension; while, increased the refractive index and viscosity. During storage, the particle size of αtocopherolloaded nanoemulsions decreased; whereas, that of αtocopherolfree nanoemulsions increased in a temperaturedependent manner. Irrespective of the storage temperature, surface tension values of antioxidantloaded nanoemulsions remained constant. However, their viscosity values increased. Antioxidant incorporation fairly increased the nanoemulsions stability likely due to partitioning at the interface. TEM micrographs confirmed the results obtained by static light scattering. The results of this study may help the rational design of functional foods using nanoemulsionbased delivery systems.