Pickering emulsions stabilized by luteolin micro-nano particles to improve the oxidative stability of pine nut oil

Pine oil contains a high percentage of polyunsaturated fatty acids, which make it prone to oxidation. Luteolin (LUT) micro-nano particles with antioxidant properties can be used as stabilizers to form an edible oil-in-water Pickering emulsion to improve the oxidative stability of pine nut oil.

Under optimal preparation conditions, the LUT micro-nano particles and pine nut oil account for about 0.44 and 90.9 g·kg^-1 of the total mass of the emulsion, respectively. The LUT particles in the suspension have a mean particle size of about 479 nm, present a sheet-like structure with a cut surface of 30-50 nm, and can reduce the surface tension of deionized water. In the optimized Pickering emulsion, the emulsion droplets are approximately spherical and have a mean diameter of about 125.6 nm and uniform distribution. The optimized Pickering emulsion droplets can remain stable for up to 2 h in an environment where the pH levels are 7-8.5, ultraviolet B radiation (UVB) irradiation, of less than 5.0 g·kg^-1 , and at a temperature of 80 °C. The stability of the emulsion in simulated digestive fluid changed minimally. In the first 7 days of the accelerated oxidation experiment, LUT micro-nano particles not only successfully protected the integrity of emulsion droplets but also fully inhibited the peroxidation of pine oil.

The strong antioxidant properties of LUT micro-nano particles, and the dense protective layer they formed, stabilized the Pickering emulsion successfully. The particles also improved the oxidation stability of pine nut oil. © 2020 Society of Chemical Industry.