Colour differences among carcasses graded with similar score for conformation and fatness

Abstract

In a population of 268 yearling bulls, those carcasses graded as U 2 , U 0 or U 1 for beef carcass conformation (n 5 240) and those graded as 2 2 , 2 0 or 2 1 for beef carcass fatness (n 5 213) were selected to study the efficiency of carcass weight, carcass dimensions and instrumental colour of latissimus dorsi, rectus abdominis and subcutaneous fat, to discriminate among these carcass grades, in a population of high-muscled and very lean carcasses from young bulls. The increase in conformation grade meant an increase in carcass weight and perimeter of the leg. Classifiers use attributes characterizing muscular development and carcass profiles from a general impression of the whole carcass. There were no significant differences for carcass weight or carcass dimensions, among the carcasses classified according to the three fat classes. The a* and b* coordinate values for the latissimus dorsi muscle were observed to decrease significantly as the carcass conformation score increased (P , 0.05). However, muscle and subcutaneous fat of fatter carcasses showed higher a*, b* colour coordinates and chroma (C*) values than leaner carcasses. The CIE (Commission International de l'É clairage) L*, a* and b* colour coordinate measurements taken on the carcasses 45 min post mortem varied significantly from the readings taken after hanging for 24 h (P , 0,001). The higher a* and b* values on the carcasses chilled for 24 h could be caused by oxygenation of both subcutaneous fat, and latissimus dorsi and rectus abdominis muscles in the time elapsing after slaughter and after carcass exposition to circulating air in the cooler for 24 h. Lightness of the latissimus dorsi muscle underwent a decrease, compared with an increase in the rectus abdominis muscle. Hardening of the subcutaneous fat during cold storage may exert an influence on the decrease in lightness observed. These differences in carcass colour during chilling storage would suggest that the relationship between carcass colour and conformation grades was higher shortly after slaughter. Both L* colour coordinate of fat colour (P , 0.01) and a*, b* and C* colour coordinates of latissimus dorsi muscle (P , 0.05) were related to conformation classification. Colour was more efficient to differentiate conformation than fat cover classes. Sixty-two percent of carcasses were correctly classified for conformation by colour differences but only 37% of carcasses were correctly classified for fatness by colour.

Effects of a quantitative trait locus for increased muscularity on carcass traits measured by subjective conformation and fat class scores and video image analysis in crossbred lambs

“…Carcass compactness has been reported to have correlated with subjective conformation score, perimeter of the leg and width of the leg, and strongly correlated with cold carcass weight (Diaz et al, 2004;Albertí et al, 2005;Indurain et al, 2008). The appearance of 'blockiness' of the whole carcass has been shown to have a positive influence on conformation score (Indurain et al, 2008).…”

“…The appearance of 'blockiness' of the whole carcass has been shown to have a positive influence on conformation score (Indurain et al, 2008). The use of this index as a measure of carcass value could be possible with the introduction of VIA systems in UK lamb abattoirs.…”

Eléménts de maîtrise de la couleur des viandes chez les bovins de race Charolaise

“…Ils sont également en accord avec l'étude de Keane et Allen (1999) qui indique que des boeufs de 720 kg de poids vif conduisent à des viandes plus jaunes (avec un indice b* supérieur) que celles des boeufs moins lourds (640 kg). En revanche, il semble que l'augmentation conjointe du poids de carcasse et de la conformation (307 à 340 kg ; U-à U+) entraîne une diminution des indices de jaune et de rouge du muscle latissumus dorsi (Indurain et al 2008), les conformations supérieures étant en général associées à une proportion supérieure de fibres blanches, moins pigmentées que les fibres rouges (Jurie et al 1995).…”

Instrumental colour measurement as a tool for light veal carcasses online evaluation

“…The reflectance spectrum obtained by spectrophotometry, as well as the trichromatric coordinates of CIE L*a*b*, are fast, non-destructive, online and readily available methods to determine meat colour (Ripoll et al 2008). Instrumental methods based in spectra of colour are able to appreciate individual L*, a*, b* coordinates, as reported by Denoyelle & Berny (1999) and Indurain et al (2008) in surface of veal carcases in the abattoir. Furthermore, studies on meat colour have reported a positive correlation between the a* index and the visual evaluation of colour by consumers (Chan et al 1995).…”