Effects of the variety and oil extraction method on the quality, fatty acid composition and antioxidant capacity of Torreya grandis kernel oils

In this study, profiles of lipid characterization and free radical scavenging capacity of Torreya grandis (T. grandis) kernel oils obtained from two varieties (T. grandis Fort. ex. Lindl. and T. grandis Fort. var. Merrillii) using three techniques (hot pressing, cold pressing and solvent extraction) were investigated and compared. The contents of the main fatty acids (linoleic, oleic, sciadonic and palmitic acids) in the T. grandis Fort. ex. Lindl. and T. grandis Fort. var. Merrillii kernel oils showed significant differences (P < 0.05). T. grandis Fort. ex. Lindl. kernel oils exhibited higher phytochemicals and free radical scavenging capacities. Meanwhile, hot pressed kernel oils presented much higher antioxidant abilities than the cold pressed and solvent extracted kernel oils, which were mainly correlated to the amounts of α-tocopherol, β-tocopherol, β-sitosterol and polyphenols. Chemometrics was employed in order to evaluating the certain contributions of the minor components to free radical scavenging capacity of the T. grandis kernel oils, as well as to indicating the differences and similarities of the T. grandis kernel oils.