Stripped SBO
While SBO was used as received for all other heating studies, stripped
SBO, in which tocopherols and other polar compounds were removed, was
used for the interaction studies with tocopherols. Stripped SBO was
prepared by passing SBO through an aluminum oxide column using hexane as
solvent as described in the previous study (Hwang et al., 2017). About
100 ml hexane was added to a glass column, and 200 g dry aluminum oxide
was slowly added. Hexane was drained, and sand was added to form a thin
layer. SBO (300 g) and hexane (300 ml) were mixed, added to the column,
and collected into a round-bottom flask, where argon was gently blown to
prevent oxidation of stripped oil. After the SBO solution was drained,
the column was further eluted with additional hexane (500 ml). The
solvent was removed with a rotary evaporator followed by high vacuum.
The previous procedure (Hwang et al., 2017) was followed to confirm the
removell of ttocopherols in oil using HPLC. The stripped SBO was stored
at -20 ÂșC under argon until the heating study.