Fatty acid composition and volatile compounds of selected marine oils and meals

BACKGROUND: Although volatile compounds characterising seafood have been studied extensively, no similar data are available regarding the volatiles of raw materials used in fish feed. Therefore the aim of this study was to make an initial screening of the volatiles of various common marine raw materials used in the aquaculture feed industry. Nine commercial marine oils (German (GFO1, GFO2 and GFO3) and Norwegian (NFO) fish oils and salmon (SO1 and SO2), tuna (TO), sardine (SRDO) and shrimp (SHO) oils) and eight commercial marine meals (Peruvian (PFM1 and PFM2), Danish (DFM1 and DFM2) and prime quality (PQFM1 and PQFM2) fish meals and Antarctic krill meals (KM1 and KM2)) were analysed for their fatty acid profiles and volatile flavour compounds. The relation between fatty acids and volatiles was examined. RESULTS: The highest polyunsaturated fatty acid and eicosapentaenoic acid (20:5ω3) contents and ω3/ω6 ratio were found in NFO. The fatty acid composition of all marine meals except krill meals was found to be more variable among batches than that of marine oils. Regarding volatiles, all marine raw materials were characterised by the complete absence or negligible levels of eight‐ and nine‐carbon alcohols and carbonyls. All marine oils were found to have high 2‐ethyl furan, 2‐methylenebutyl cyclopropane, hexanal, 2,4‐octadiene and 3,5‐octadiene contents. Marine meals, unlike marine oils, were characterised by the almost complete absence of unsaturated and cyclic hydrocarbons and terpenes and very low levels of furans. CONCLUSION: Volatiles of marine meals differ from those of marine oils. Unlike fatty acids which give useful traceability information, volatiles seem to fail in this role owing to their strong variability. Copyright © 2008 Society of Chemical Industry