2.2.3. Fatty acid and proximate analyses
Fatty acid methyl esters (FAME) were prepared by methylation of
total lipids as described by HartmanandLago (1973).Methyl esterswere
separated by gas chromatography in a Varianmodel 3380 equippedwith
flame ionization and a cyanopropyl capillary column (100m×0.25 i.d.,
0.25 μmfilmthickness, CP-7420 Varian, EUA). The injector and detector
temperatures were 220 °C and 240 °C, respectively. The gas flow rates
used were 1.4 mL min−1 carrier gas (H2), 30 mL min−1 make-up gas
(N2)and300mLmin−1 flamegasses (H2 and synthetic air, respectively).
The sample splitting rate was 1:80. The operation parameters were:
column temperature 165 °C for 12 min, programmed to increase at 4 °C
min−1 to 180 °C and kept at this temperature for 15 min; next, it was
increased to 240 °C at 15 °C min−1; the total run time was 35 min. The
peak areas were determined by the Workstation 5.0 (Varian) data
acquisition program. For fatty acid identification, retention times were
compared with those of standard methyl esters.