Influence of different extraction methods on the chemical composition, antioxidant activity, and overall quality attributes of oils from Trichosanthes kirilowii Maxim seed

Trichosanthes kirilowii Maxim seed oil is full of nutrition and exerts positive effects on the health of humans. The study detected and compared the quality characteristics, the lipid composition and active constituents of Trichosanthes kirilowii Maxim seed kernel and shell oil. This study used four extraction techniques: cold pressing, ultrasonic-assisted solvent extraction, supercritical fluid extraction, and subcritical butane extraction. The results indicated that the highest lipid yield (36.75%) was obtained by ultrasonic-assisted solvent extraction, while the lowest (32.24%) was obtained by supercritical fluid extraction. Meanwhile, Trichosanthes kirilowii Maxim seed oil is rich in linoleic acid (25.64–31.24%) and α-tocopherol (247.76–702.28 mg/kg). The extraction method and shells significantly affected beneficial phytochemicals (tocopherols, phytosterols and total phenols) and antioxidant activity (DPPH) (p < 0.05). Moreover, the tocopherols of supercritical fluid extraction oil (1020.15–1052.55 mg/kg) and the phytosterols of cold pressing oil (1033.84–1748.20 mg/kg) were higher than that of other methods under the same conditions. The content of sterols and tocopherol in the seed kernel oil is higher than that of the seed shell oil. Meanwhile, cold pressing oil had more abundant volatile compounds. The above information is valuable for manufacturers to select the appropriate method to produce Trichosanthes kirilowii Maxim seed oil with the desired quality attributes and chemical compositions for the target end-user.