Impact of supercritical carbon dioxide turmeric extract on the oxidative stability of perilla oil

The objective of this study was to determine the efficacy of supercritical carbon dioxide turmeric extract (STE) on the oxidative stability of perilla oil (PO), as measured by acid value (AV), peroxide value (PV) and oxidation induction time and compared to control and α-tocopherol containing PO as a positive control. The antioxidant activity was determined by DPPH, ABTS and FRAPS assays and individual bioactive compounds identified by chromatography. STE demonstrated significantly higher antioxidant activity than the α-tocopherol. The major components of the STE were identified as ar-turmerone, turmerone, curlone and bisabolene by GC-MS and curcumin and demethoxycurcumin by UPLC-Q-TOF MS. During thermal treatment at 65 °C for 24 h, the PO containing STE at different concentrations (100, 300, 500 and 1000 μg mL⁻¹) had significantly lower AV and PV, and at least 1.5 times higher induction period than those of the control and α-tocopherol-incorporated PO.