Contribution of pigment content, myoglobin forms and internal reflectance to the colour of pork loin and ham from pure breed pigs

In the present study, the effect of type of stunning (electrical v. gas) and the gas mixtures in a modified atmosphere (MA) packing system (MA-A: 30% CO 2 1 70% O 2 ; MA-B: 30% CO 2 1 69.3% N 2 1 0.7% CO; MA-C: 40% CO 2 1 60% N 2 ) on light lamb meat quality, obtained by 20 males of Manchego Spanish breed, was evaluated at 7, 14 and 21 days post packing. For all ageing times, gas-stunned groups reached the highest pH ( P , 0.001) and shear force (SF) values (P , 0.05), and at 21 days, water losses were highest; in contrast, meat colour coordinates were lower ( P , 0.001). In general, MA-B showed the highest stability for colour coordinates whereas the lowest tenderness (high SF) was found on MA-A. In this study, the gas mixture with a low carbon monoxide level (MA-B) promoted a higher colour stability and good tenderness, in comparison to the other two blends. In contrast, the conventional packaging system (type A, high oxygen levels) had a reduced tenderness and major colour instability.

Section: Gas)supporting

confidence: 60%

Section: Gas)supporting

confidence: 53%

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Light lamb meat quality packed under modified atmospheres: effect of stunning systems (electrically v. gas)

Linares

Vergara

2009

“…Pigments contain iron, and thus make meat nutritionally important to humans. Lindahl et al (2001) found that 90% of the variation in the a* value of LD and M. biceps femoris was explained by the content of pigment and the size of the fractions of myoglobin oxidised from blooming.…”

Section: Heritabilitiesmentioning

confidence: 99%

Genetic parameters of meat quality traits in two pig breeds measured by rapid methods

Gjerlaug-Enger

Aass

Ødegård

et al. 2010

To study genetic variation in meat quality traits measured by rapid methods, data were recorded between 2005 and 2008 on samples of M. longissimus dorsi (LD) in Landrace (n 5 3838) and Duroc (n 5 2250) pigs included in the Norwegian pig breeding scheme. In addition, ultimate pH levels in the glycolytic LD (loin muscle) and M. gluteus medius (GM, ham muscle), and in the oxidative m. gluteus profundus (GP, ham muscle) were recorded as an extended data set (n 5 16 732 and n 5 7456 for Landrace and Duroc, respectively) from 1998 to 2008. Data were analysed with a multi-trait animal model using AI-REML methodology. Meat from Duroc had considerably more intramuscular fat (IMF), less moisture and protein, appeared darker with higher colour intensity and had lower drip loss than meat from Landrace. The heritability estimates (s. in LD all demonstrated moderate-to-high genetic variation for these traits in both breeds. Near infrared spectroscopy and EZ-DripLoss are modern technologies used in this study for the determination of chemical components and drip loss in meat. These methods gave higher heritabilities than more traditional methods used to measure these traits. The estimated genetic correlations between moisture and IMF in Duroc, and pH and drip loss in Duroc were both 20.89. Interesting differences between the two breeds in numerical value of some genetic correlations were observed, probably reflecting the differences in physiology and selection history between Landrace and Duroc. The estimated genetic correlation between drip loss and pH was much stronger in Duroc than in Landrace (20.89 and 20.63, respectively). This might be due to the high pH in Duroc, whereas Landrace had a lower pH closer to the iso-electric point for muscle proteins. The positive genetic correlation between the L* value in meat and IMF in Duroc (0.50) was an effect of differences in visible marbling, rather than meat colour. For Landrace, this correlation was negative (20.20). IMF content showed favourable genetic correlations to drip loss (20.36 and 20.35 for Landrace and Duroc, respectively).

“…Yellowness (b*) value generally varies in the same direction of L* (Franck et al, 2000). According to these authors, the higher L* and b* values could be explained by a less reductive environment that promotes oxygenation of myoglobin to MbO 2 (Lindahl et al, 2001). …”

Section: Post-slaughter Measurementsmentioning

confidence: 99%

Podolian beef production on pasture and in confinement

Braghieri

Pacelli

Rosa

et al. 2011

the effect of rearing system (confined (C) v. free ranging (FR)) and season (spring v. summer) was evaluated on behaviour, immune and blood parameters and beef production (experiment 1). From February to August 2008, the effect of rearing system was only evaluated on beef production (experiment 2). A total of 12 Podolian young bulls were used each year. They were slaughtered at 18 and 15 months of age in 2007 and 2008, respectively. Herbage mass and pasture composition were monitored during the 2 years. Pasture availability, in terms of herbage mass and composition, as well as its seasonal development, was similar in the 2 years. In the first experiment, FR animals spent more time walking ( P , 0.05), feeding ( P , 0.001) and standing ( P , 0.01) and showed a lower number of agonistic ( P , 0.05) and non-agonistic social interaction than C animals ( P , 0.01). Significant lower concentrations of serum urea nitrogen ( P , 0.001) and creatinine ( P , 0.10) in FR animals indicated a lower protein nutritional status due to inadequate protein availability at pasture. As a consequence, average daily gains ( P , 0.05), slaughter weight ( P , 0.05) and body condition score ( P , 0.01) were lower in grazing animals as compared with C bulls. Cellular immune responsiveness was higher in FR animals ( P , 0.05). Similarly, antibody titre to keyhole limpet hemocyanin was higher in FR bulls at the 2nd and 3rd month after antigen injection ( P , 0.05), whereas it tended to be higher at the 4th month ( P , 0.10). In both experiments, grazing negatively affected meat colour in terms of lightness. Eighteenmonth-old bulls also showed lower final weight, weight gain and body conditions when kept outdoor: a possible consequence of nutrient deficits, as suggested by the metabolic status of FR animals. The same animals, however, benefited from FR in terms of natural behaviour expression and immune responsiveness. When the experiment was replicated the subsequent year, on animals slaughtered at 15 months of age, no differences between the performances of FR and C animals were detected. The earlier slaughter age system was also proportionally less dependent on external inputs as grazing was not extended to the dry season when herbage mass availability was lower.