Antioxidant stability of colloidal tea polyphenols in tea seed oil
Liwen Hu, Ting Li, Qi Luo, Jinsheng Zhang
Abstract
Tea polyphenols were infused into tea seed oil in ethanol, and the ethanol was removed by vacuum distillation to prepare colloidal tea polyphenols in tea seed oil. The stability of the colloidal tea polyphenol samples decreased with increasing added tea polyphenols amount. Residual ethanol in the colloidal system was detected by gas chromatography (GC), yielding a concentration range of 0.30 ± 0.02 to 1.57 ± 0.01 g/kg, and ethanol was not detected in the tea seed oil blank. High performance liquid chromatography (HPLC) was used to analyze tea polyphenols in the colloidal system, and the results proved that the tea polyphenols underwent no chemical changes after being added to tea seed oil. Tyndall phenomena were observed in all colloidal tea polyphenol samples. Using the Schaal oven method to compare the peroxide value changes of tea seed oil with synthetic antioxidants, tea polyphenol palmitate and colloidal tea polyphenols, we found that the antioxidant stability of colloidal tea polyphenols in tea seed oil was better than that of synthetic antioxidants and tea polyphenols palmitate, and the optimal added amount range of tea polyphenols in tea seed oil was 0.1–0.2 g/kg. Practical applications Colloidal tea polyphenols can be stably and uniformly dispersed in oils to improve the antioxidant stability of the oils. Colloidal tea polyphenols in oils with lower residual ethanol content are safe to consume and can extend the storage time of oils. Tea polyphenols as natural antioxidants, can replace synthetic antioxidants. Therefore, colloidal tea polyphenols have potential application prospects in the oil industry and in commercial development.