Effect of two sous-vide cooking methods on fatty acid composition and oxidative stability of longissimus thoracis muscle from pigs receiving a diet containing or not extruded linseed
To verify the effects of two different sous-vide cooking conditions
on lipid oxidation and fatty acid (FA) composition of longissimus
thoracis (LT) muscle, 24 pigs, evenly divided into two groups of
12 subjects each, were used. One group received a barley-soya
bean meal diet (C) and the second was given the same feed where
5% of extruded linseed partly replaced barley, to obtain a n-3 FA
enriched diet (L). At slaughter, from each left half carcase, two
samples of LT muscle were collected, packed under vacuum and
stored at −18 °C until analysis. The samples were cooked in water
bath according to two different methods: at high temperature
(80 °C) and short-time i.e. samples left until the core temperaturereached 70 °C (A); at low temperature (60 °C) and long-time
(15 h) (B). After cooking, the samples were refrigerated (2 °C)
for 24 h. Oxidative stability was measured by a dosage of the
2-thiobarbituric acid reactive substances (TBARS) content,
expressed as milligrams of malondialdehyde (MDA)/kg of meat,
and FA composition was determined by capillary gas chromatography.
The content of each fatty acid is expressed as a percentage
of the total FAs detected. The statistical analysis was performed
by means of ANOVA, using the GLM procedure of SAS. Dietary
treatment (C vs. L) and cooking condition (A vs. B) were used as
independent variables. The different sous-vide cooking conditions
affected neither lipid oxidation nor FAs percentage of LT
muscle. Extruded linseed feeding brought about an increase of
the percentage of total n–3 FA (2.67 vs. 0.98; p<.01) and also of
polyunsaturated fatty acids (12.02 vs. 9.68; p<.01) in intramuscular
fat but did not affect lipid oxidation. This enabled to obtain
pork with a more favourable n–6/n–3 ratio (3.68 vs. 10.42 in L
and C group, respectively; p<.01), according to the global health
guidelines. Thus, an enriched linseed diet ameliorates the FA
composition of pork. The effect of the two different sous-vide
cooking methods on lipid composition and oxidative stability of
pork does not differ, irrespective of dietary treatments
