Further refining
Silflower oil was further refined to reduce the chlorophyll level with
three different bleaching clays, bentonite, sepiolite, and Tonsil®
following the previous method (Kwaśnica et al., 2022; Strieder et al.,
2017). In brief, oil (40.0 g) was dried with a vacuum pump for 30 min at
100 °C, 2.0 g of bleaching clay was added, heated at 100 °C with
stirring for 20 min under argon, and filtered through a pre-layer of
celite. Tonsil® was used as received while bentonite and sepiolite were
activated by following the previously reported methods (Saneei et al.,
2015; Sarioğlan et al., 2010; Srasra et al., 1989).