CRBO was added to a 50mL tube with a Teflon-lined screw
cap as described by Shiu et al. (2010). Potassium hydroxide solution
(10 mL; 2 N) was added under nitrogen, and the tube was
closed with screw cap. The tube was then heated at 60 ◦C until
the saponification reaction was completed (overnight), as verified
by analytical TLC (silica gel; eluted with a mixture solvent,
hexane/ethyl-acetate/acetic-acid = 90:10:1, v/v/v). The mixture
containing saponified matter was acidified to pH 2 by using sulfuric
acid and the reaction was completed in about 1 day. Water was then
added to the mixture to stop the reaction, and unsaponifiable matter
was separated by extraction using n-hexane/water. The hexane
extract, which contains fatty acids, was collected and the hexane
was removed.
The fatty acids were then converted into their corresponding
fatty acid methyl esters (FAMEs) by heating with sulfuric acid
in methanol at 60 ◦C and the reaction was completed in about 1
day, as verified by analytical TLC (silica gel; eluted with a mixture
solvent, hexane/ethyl-acetate/acetic-acid = 90:10:1, v/v/v). FAMEs
were separated by extraction using n-hexane/water. The hexane
extract, which contains FAMEs, was collected. After the hexane was
removed, the remaining substance was referred to as the reaction
product. The product was analyzed by TLC and gas chromatography
(GC).