The samples were incubated for 16 h in
freezer at 25 C with the aim of complete transesterification and
then the reaction was stopped by the addition of slightly acidic NaBr
solution neutralizing the reaction mixture. The organic phase was
evaporated under gentle stream of nitrogen in the room temperature
to approximately 100 mL and extracted by 600 mL hexane twice
(the organic phase was discarded) in order to remove remained fatty
acid methyl esters.