The antioxidant capabilities of anthocyanin and tocol extracts from black rice bran were evaluated using
an emulsion system containing either cholesterol (1.0 mg/ml) or fish oil (10 mg/ml). The cholesterol oxi-
dation product, 7-ketocholesterol, increased to 180.1 l g/ml in the control emulsion after 168 h of oxida-
tion, while it was only 15.4 and 39.0 l g/ml in the emulsions containing 1 l g/ml of the anthocyanin and
tocol extracts, respectively; but below 1.2 l g/ml in the emulsion having 5 l g/ml of anthocyanins or
tocols. In the fish oil emulsion, over 80% of C20:5 and C22:6 were oxidised after a 48 h incubation at
37 ?C, while they were retained above 38% and 65% in the emulsions containing 10 l g/ml of anthocyanins
and tocols, respectively, and above 85% in the emulsion containing 20 l g/ml of anthocyanins or tocols.
Compared with the tocols extract, the capability of the anthocyanin extract was relatively greater in sta-
bilising cholesterol but lower in inhibiting fatty acids oxidation.
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