| he grape seed oils were prepared by subcritical fluid extraction, supercritical CO2 extraction, solvent extraction, cold pressing and hot pressing, and the effects of oil extraction processes on polyphenols and antioxidant activity of grape seed oil were studied. The results showed that the polyphenol content in subcritical oil was the highest, and the contents of total phenols, flavonoids and flavan-3-alcohol were 418.56, 155.60 mg/kg and 75.50 mg/kg, respectively.The polyphenol content in supercritical oil was the lowest, and the contents of total phenols, flavonoids and flavan-3-alcohol were 23.15, 087 mg/kg and 5.81 mg/kg, respectively. Quantitative analysis of seven mono-phenols in grape seed oil showed that compared with other oil extraction processes, the mono-phenols contents in subcritical oil were higher, and the contents of gallic acid,epicatechin and catechin were 625.09, 650.35 μg/100 g and 565.40 μg/100 g. The protocatechuic acid content in hot pressed oil was the highest, which was 541.56 μg/100 g. DPPH,ABTS,ORAC and Fe3+ reduction experiments showed that the antioxidant activity of subcritical oil was the highest. Except for protocatechuic acid, the polyphenols of grape seed oil were significantly and positively correlated with antioxidant activity. |
