Application of nanostructured lipid carriers containing α-tocopherol for oxidative stability enhancement of camelina oil

Abstract

In the present study, nanostructured lipid carriers (NLCs) were prepared using the hot homogenization method with high shear force. The optimal amounts of solid/liquid lipids ratio (glyceryl stearate/oleic acid), the aqueous phase of surfactant (tween 80/water), and α-tocopherol (αt) as constituents of NLCs were obtained using response surface methodology via Box–Behnken design and the encapsulation efficiency and loading capacity percentages of NLCs containing αt (NLCs- αt) were recorded as responses. The optimum NLCs-αt characterized in terms of particle size, particle size distribution index (PDI), scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transfer spectroscopy infrared (FTIR) analyses. The results indicated that NLCs in the optimum point had a particle size of 198 nm and PDI of 0.28 with a spherical shape and a smooth surface. The results of DSC and FTIR analyses showed that there is no interaction between the active compounds and obtained NLCs. The release behavior of αt from NLCs-αt in the simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) revealed that the\\orsmeyer-Peppas model was the best model for the evaluation of the release kinetic of αt. It was observed that the addition of NLCs-αt reduced the DPPH radical scavenging (83.33–46.25%), TPC (228.8–169.0 mg GAE/g) and oxidative stability (4.21–3.30 h), but increased peroxide value (0.87–2.59 meqO2.kg−1), anisidine value (0.63–1.50) and TOTOX value (2.37–6.68) after 90 days of storage. Moreover, the antioxidant activity of Camelina oil containing optimum NLCs-αt (46.25%) was comparable to Camelina oil containing the TBHQ (49.45%) as a reference, but it was higher when rosemary essential oil (REO) was added with NLCs-αt (58.73%) (after 90 days of storage). In general, it can be concluded that the optimum NLCs have tremendous potential for encapsulation of αt and deliver the extraordinary antioxidant effect to Camelina oil when they are added to Camelina oil with REO.