2. Methods
2.1. Reagents
Grape seeds (type airen) were supplied by the CRISVE winery of
Socuéllamos (Ciudad Real, Spain) with a natural moisture of 10
wt.%. The following chemicals were supplied by MERK: hexane
(>95%); pentane (99%); acetonitrile (99.9%); standards of tocopherols
and tocotrienols (>95%). The following chemicals were supplied
by PANREAC: acetone (99.5%); diethyl ether (99.7%);
methanol (99.8%); ethanol (96%); dichloromethane (99.5%); talc
(>99.5%); potassium hydroxide aqueous solution (0.1 N); phosphoric
acid (87%); and sodium hydroxide (98%). The following chemicals
were supplied by FLUKA: heptane (puriss. p.a., P99.5% GC);
methyl heptadecanoate (puriss. p.a., standard for GC, P99.7%). Triacetin
(99%) was supplied by ALFA AESAR. The following chemicals
were necessary for the measure of iodine value and were supplied
by PANREAC: cyclohexane, Wij’s reagent, sodium thiosulphate ethanolic
solution (0.1 N) and potassium iodide. Bioethanol (99.9%)
was supplied by BIOETANOL DE LA MANCHA, S. L. The catalyst
(potassium methoxide) was 97% purity from BASF