Abstract:

Oat oils extracted by supercritical carbon dioxide fluid (SCF-CO2) with and without ethanol added as entrainer and those extracted with n-hexane or methanol were compared for differences in fatty acid composition and DPPH free radical scavenging activity. GC analysis showed that the fatty acid composition of 4 oat oils mainly consisted of palmitc acid, elaidic acid and linoleic acid and they together accounted for 93% of total fatty acid in each oat oil. Oat oils extracted by SCF-CO2 with and without ethanol added as entrainer and those extracted with n-hexane or methanol exhibited relative contents of unsaturated fatty acids of 79.41%, 77.86%, 77.56% and 76.51% and ratios of saturated fatty acids to monounsaturated fatty acids to polyunsaturated fatty acids of 1:2.74:1.85, 1:2.08:1.71, 1:2.21:1.60 and 1:1.74:1.73, respectively. The DPPH free radical scavenging activity of the oat oils and vitamins C and E decreased in the following order: vitamin C＞oat oil extracted with methanol ＞oat oil extracted by SCF-CO2 with ethanol added as entrainer＞vitamin E ＞oat oil extracted with n-hexane＞oat oil extracted by SCF-CO2 without ethanol added as entrainer.

Key words: oat oil, supercritical carbon dioxide fluid extraction, GC, DPPH free radical scavenging activity