Rosehip oil nanoemulsion as a stable delivery system for omega-3 fatty acids to enhance the nutritional value of yogurt

Abstract

Rosehip oil (REO) contains excessive amounts of polyunsaturated fatty acids (PUFA), such as Omega-3 fatty acids (OFA). OFA exhibits instability, poor solubility, and limited bioavailability upon addition to food. In this study, REO nanoemulsion was prepared by probe ultrasonication. Statistically designed experiments were used to optimize Ultrasonication time (5 min), ultrasonication amplitude (37.26 %), and the surfactant (1 %Tween 20) concentration (surfactant to oil ratio of 1.17:1). The spherical morphology of the nanoemulsion was studied using scanning electron microscopy. REO was further characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The droplet size of REO nanoemulsion increased from 60 to 88 nm during storage at 4 ⁰C for 28 days. The nanoemulsion had an encapsulation efficiency of 89.7 %, and it was stable based on thermodynamical study. The fatty acid profile confirmed that REO nanoemulsion could preserve linoleic acid compared to the direct addition of REO in yogurt. The sensory study revealed that REO nanoemulsion could mask the tartness of REO when incorporated into yogurt. This study proved that nanoemulsion is a potential tool to enhance the stability of OFA in food systems.