Sammendrag
The evolution of fatty acid classes (SFA, MUFA, and PUFA) in neutral lipids (NL) and phospholipids (PL) in pigs were studied. The M. biceps femoris in green hams from Norwegian breeds Landrace (LR), Duroc (DU), and Hampshire (HS) slaughtered at 6, 7.5, and 9 mo of age were examined. The parameters were analyzed for age and breed effects with and without adjustment for NL or PL content. The fatty acid class contents of NL were not significantly different between the age groups. However, when NL content was adjusted, deposition of SFA and MUFA in NL significantly increased and deposition of PUFA in NL significantly decreased with age. Duroc had consistently higher fatty acid class contents, but after adjusting for NL content, only the deposition of SFA proved to be genetically different. The nonlinear relationship between NL content and MUFA and PUFA, together with the genetic potential of HS to deposit less SFA than LR, gave significantly different fatty acid class compositions between the breeds. The content and proportion of MUFA in PL increased with age. Specific ratios were also determined. The fat firmness index, C18:0/C18:2n − 6 in NL, increased with age and was lowest in HS due to genetics and highest in DU due to its high NL content. The sensory rancidity index C18:1n − 9/n − 6 increased in NL and decreased in PL between 7.5 and 9 mo. The C18:1n − 9/n − 6 in NL was highest in DU due to higher NL content. The n − 6/n − 3 in NL and PL increased between 7.5 and 9 mo.
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