Oxidative Stability and Antioxidant Activity of Crude Jojoba Oil

抄録

The seeds of jojoba [Simmondsia chinensis (Link) Schneider] contain a unique oil known as jojoba oil. It mainly consists of liquid wax monoesters with structures similar to human sebum wax and is popular as a cosmetic ingredient. We previously observed that the oxidative stability and antioxidant activity of crude jojoba oil are higher than those of many other vegetable oils. In this study, these two parameters were determined and compared among crude jojoba oils from different companies, countries, and years of production, together with deodorized or refined oils. Oxidative stability and antioxidant activity vary among crude oils, and there was a negligible correlation between these two parameters. Both deodorized and refined oils showed lower antioxidant activities than crude oils. In addition to wax esters, triglycerides and squalene are other major oil components of human sebum. To compare the autooxidation of jojoba oil (wax ester), olive oil (triglyceride), and squalene, we measured their acid, peroxide, and carbonyl values after heat treatment at 60°C for 60 d. The acid value did not change in jojoba oil but increased in the other ones. In addition, the peroxide and carbonyl values were the lowest in jojoba oil following heat treatment. These results suggest that jojoba oil was the most stable in terms of autooxidation among these three investigated oils. Finally, we determined the cytotoxicity of olive and jojoba oils in human epidermal cells, and concluded that they were non-toxic after heating at 60°C for 30 or 60 d.