2.3 Fatty acid analysis
The fatty acid composition was determined as fatty acid methyl esters
(FAMEs) by capillary gas chromatography analysis after alkaline
treatment (Christie, 1982). Methyl tridecanoate (C13:0, 2 mg/mL) was
used as internal standard and FAMEs were measured on a GC 2010 Plus gas
chromatograph (Shimadzu Corporation, Kyoto, Japan) equipped with a flame
ionisation detector (FID) and an AOC-20s auto sampler (Shimadzu
Corporation), at the same conditions reported in Marzocchi, Pasini,
Baldinelli & Caboni (2018). Peak identification was accomplished by
comparing peak retention time with GLC-463 standard mixture from
Nu-Check (Elysian, MN, USA) and FAME 189-19 standard mixtures from
Sigma-Aldrich Chemicals (St. Louis, MO, USA) and expressed as weight
percentage of total FAMEs. FAMEs composition was measured in 2
replicates for each lipid extract (n = 4) and each analysis
lasted 7 minutes.