Fatty acid composition and squalene analysis
First, oil samples were converted to fatty acid methyl esters (FAME) by
dissolving oil samples (about 10 mg) in 1.4 ml hexane followed by adding
2 N methanolic KOH (200 μL) and shaking for 2 min with a Vortex mixer
(Ichihara et al., 1996). After two layers were separated, the top layer
was transferred to a vial, and then analyzed with a Shimadzu 2010 gas
chromatograph (Shimadzu, Columbia, MD) with a flame ionization detector
(FID). The column was a Phenomenex (Torrance, CA) ZBFAME capillary
column (30 m × 0.25 mm ID × 0.20 μm film). The GC conditions were the
same as reported by Winkler-Moser et al. (2023). Commercial FAME and
squalene standards were used to identify peaks in the GC chromatograms.
The average values of relative peak areas measured in duplicate are
reported.