反应详情

Beta-carotene bleaching (BCB) assay for kenaf seed and commercial edible oils were determined according to the protocol described by Kumazawa et al. (2002). α-tocopherol was used as the standard lipophilic antioxidant in this test. In brief, 3 ml of beta-carotene solution (100 μg/ml chloroform) (Sigma-Aldrich Co., St. Louis, Mo., USA) was added to 40 mg of linoleic acid (Sigma-Aldrich Co., St. Louis, Mo., USA) and 400 mg of Tween 20 (Fisher Scientific, Loughborough, Leicestershire, UK). Then, the mixture was mixed well and dried under nitrogen stream. Immediately, 100 ml of distilled water was added to the dried mixture to form a beta-carotene/linoleic emulsion. One and half milliliters of emulsion were added with 20 μl of methanol (control) or sample at the concentration of 5 mg/ml methanol. After that, the sample was incubated in water bath at 50° C. for one hour. Finally, the absorbance of the sample was measured at 470 nm against distilled water (blank) by using a UV-Visible spectrophotometer (Pharmaspec uv-1700, Shimadzu, Kyoto, Japan).

1. additionThen, the mixture was mixed well
2. customdried under nitrogen stream
3. additionImmediately, 100 ml of distilled water was added to the dried mixture