Materials
Unhulled silflower seeds were provided by The Land Institute (Salina,
KS, USA). Unhulled sunflower seeds were purchased from Nuts.com
(Cranford, NJ, USA). Gallic acid, Folin-Ciocalteu reagent, sodium
carbonate, ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6-sulphonic
acid)), Trolox® (6-hydroxy-2,5,7,8-tetramethlchroman-2-carboxylic acid),
ammonium thiocyanate, barium chloride, iron (II) sulfate heptahydrate,
2,2,4-trimethylpentane (isooctane), citric acid, Fuller’s earth, and
sepiolite were purchased from Sigma–Aldrich (St. Louis, MO, USA).
Bentonite was purchased from Spectrum Chemical Mfg. Corp. (New
Brunswick, NJ, USA), and Tonsil® was kindly provided by Clariant
(Munich, Germany). Silica gel 60 (70-230 mesh) and thin layer
chromatography (TLC) plates (MK6F silica gel 60 Å) were purchased from
EMD Chemical Inc. (Darmstadt, Germany) and Whatman (Clifton, NJ, USA),
respectively. Hexane, ethyl acetate, acetone, THF, methanol, ethanol,
potassium hydroxide, sodium hydroxide, and hydrochloric acid solution
were purchased from Fisher Scientific (Fair Lawn, NJ, USA).