Introduction
Muscle lipids are mainly composed of neutral lipids (NL) and
phospholipids (PL) and are involved in many of the sensory attributes
of meat and meat products. Their implications in meat
quality depend on the amount (Huang and others 2010) and on
the physical and chemical traits of NL and PL. Despite this knowledge,
few studies have broken down the intramuscular fat (IMF)
into NL and PL and analyzed their respective fatty acid compositions
with respect to developmental stage (Fiego and others 2010;
Yang and others 2010) or genetics (Cameron and others 2000;
Andres and others 2001; Armero and others 2002; Hoegberg and
others 2004; Zhang and others 2009; Huang and others 2010).
NL and PL have very different fatty acid profiles, but the overall
profile of IMF mainly reflects the proportion of NL as the animals
continue to deposit fat with age. Major changes in the overall fatty
acid composition of IMF could be due to alterations in the NL/PL
ratio, and not those occurring within NL or PL owing to different
treatments or design variables. Thus, fatness could be a confounding
factor if not accounted for (De Smet and others 2004; Wood
and others 2004; Ntawubizi and others 2010). Age (Bosch andothers 2012), breed (Wood and others 2004; Zhang and others
2009; Peloso and others 2010), and feed (Wood and others 2004)
could also be confounding factors, as these factors directly influence
fatty acid profiles or are associated with fatness. Studies
taking into account confounding effects through block designs or
statistical analysis are still lacking in the scientific literature.
Characteristics of IMF are of especial importance when the
purpose is to optimize dry-cured hams by way of the raw material.
Lengthy exposure to lipases and pro-oxidants such as salt and heme
facilitates lipid degradation, oxidation, and flavor formation. It is
generally agreed that aroma is mainly generated from PL fatty
acids. Differentiating between fatty acids associated with PL from
NL is thus preferable.
A design where rearing and feeding were controlled and standardized
seemed relevant in order to reveal detailed quality differences
related to NL and PL content and fatty acid composition.
To our knowledge, no study using both age and breed as design
variables has been undertaken before. The aim of this study was to
investigate the fatty acid composition of NL and PL of M. biceps
femoris in green hams from Norwegian breeds at slaughter ages
relevant to dry-cured ham production.