| In order to improve the added value of Ziziphi spinosae Semen oil, Ziziphi spinosae Semen was pretreated by acid hydrolysis, and Ziziphi spinosae Semen oil was extracted by petroleum ether. With the unsaponifiable matter content in the oil as an index, single factor and orthogonal experiments were used to optimize acid hydrolysis pretreatment conditions of Ziziphi spinosae Semen. The effects of acid hydrolysis pretreatment on the composition of unsaponifiable matter, yield, physicochemical indexes and antioxidant activity of Ziziphi spinosae Semen oil were analysed. The results showed that the optimal processes of acid hydrolysis pretreatment were obtained as follows: acid hydrolysis time 2.5 h, acid hydrolysis temperature 50 ℃, hydrochloric acid-ethanol solution concentration 3.0 mol/L, and solid-liquid ratio 1∶ 15. Under these conditions, the content of unsaponifiable matter in Ziziphi spinosae Semen oil was (2.29±003)%, which was increased by 3.24 times compared with that unpretreated with acid hydrolysis. The acid hydrolysis pretreatment of Ziziphi spinosae Semen did not affect the composition of unsaponifiable matter in Ziziphi spinosae Semen oil, which contained phytol, geranyl geraniol, squalene, campesterol, stigmasterol, γ-sitosterol, lupeol, and betulinicaldehyde. The acid hydrolysis pretreatment did not affect the yield, peroxide value and saponification value, but the acid value of Ziziphi spinosae Semen oil increased, and the iodine value decreased. The ability of Ziziphi spinosae Semen oil to scavenge DPPH and ABTS+ free radicals was enhanced. In conclusion, the acid hydrolysis pretreatment of Ziziphi spinosae Semen can effectively increase the content of unsaponifiable matter in Ziziphi spinosae Semen oil, and significantly improve the antioxidant activity of the Ziziphi spinosae Semen oil. |
