Effect of intramuscular fat, breed, and age at slaughter on fatty acid composition in green hams

The evolution of fatty acid classes (ΣSFA, ΣMUFA, and ΣPUFA) 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 ΣSFA and ΣMUFA in NL significantly increased and deposition of ΣPUFA in NL significantly decreased with age. Duroc had consistently higher fatty acid class contents, but after adjusting for NL content, only the deposition of ΣSFA proved to be genetically different. The nonlinear relationship between NL content and ΣMUFA and ΣPUFA, together with the genetic potential of HS to deposit less ΣSFA than LR, gave significantly different fatty acid class compositions between the breeds. The content and proportion of ΣMUFA 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/Σn - 6 increased in NL and decreased in PL between 7.5 and 9 mo. The C18:1n - 9/Σn - 6 in NL was highest in DU due to higher NL content. The Σn - 6/Σn - 3 in NL and PL increased between 7.5 and 9 mo.

Knowledge of age-related changes and breed differences in fat content and composition would be helpful in determining the optimal breed and slaughter time in terms of raw ham quality.