Materials
6–hydroxy–2,5,7,8–tetramethylchroman–2–carboxylic acid (Trolox), 1,1–diphenyl–2–picrylhydrazyl (DPPH), 2,4,6–Tripyridyl–S–Triazine (TPTZ), α–tocopherol, γ–tocopherol, gallic acid, quercetin, Folin–Ciocalteu reagent, Fatty acid methyl ester standard mixture, and other chemicals and solvents were supplied by Merck (Darmstadt, Germany), Sigma–Aldrich (St. Louis, MO, USA), and CHEMICAL CO., LTD (Miaoli, Taiwan).