Lamb meat quality of two breeds with protected origin designation. Influence of breed, sex and live weight

Abstract

Lamb meat quality of two Portuguese products was examined. The influences of slaughter weight, sex and breed on eating quality were evaluated. Data were obtained from 72 lambs of two different breeds with protected designation origin. In accord with the normal slaughter weight in the region three classes were considered: A: 9-14 kg live weight; B: 14-19 kg live weight and C: 19-24 kg live weight. pH of M. longissimus thoracis et lumborum muscle (MTL) was measured 1 h and 24 h after slaughter. Meat colour was estimated in the M. longissimus thoracis et lumborum muscle (MTL) muscle on the 12th rib using the L* a* b* system. Shear force was evaluated 72 h after slaughter. Sensorial analysis was assessed by a trained taste panel of 12 members. The pH values found could be considered within the normal pH range, between 5.5 and 5.9. When the pH measurement was made 24 h after slaughter, the heavy lambs had significant higher value than the light lambs. In relation to colour variables, live weight, sex and breed had no effect on the red index (a*). Lightness (L) decreased with increasing live weight and the light lambs had higher yellow index (b*) than the heavier lambs. Shear force increased with live weight and the Bragançano breed had a greater mean shear force than the Mirandesa (7.8 vs. 6.8 kg/cm 2 ). The heavy carcasses had more flavour intensity than the light ones. Mirandesa lambs had significantly lower values for toughness, stringy and odour intensity than Bragançana lambs.

Production factors influence fresh lamb longissimus colour more than muscle traits such as myoglobin concentration and pH

“…were small compared to the impacts of production site, year, slaughter group and intrinsic muscle factors, and compared to previously reported values (Hopkins & Fogarty, 1998;Teixeira et al, 2005). The effects of sire type on meat redness, yellowness, hue and chroma were not accounted for by differences in muscle myoglobin, iron or ICDH activity, as was the effect on meat lightness.…”

“…Certain production factors such as lamb breed, slaughter weight and nutrition influence fresh lamb meat colour (Hopkins & Fogarty, 1998;Martıńez-Cerezo et al, 2005;Priolo, Micol, Agabriel, Prache, & Dransfield, 2002;Ripoll, Joy, Muñoz, & Albertí, 2008;Teixeira, Batista, Delfa, & Cadavez, 2005). Hopkins and Fogarty (1998) reported that colourimetric measures of meat L*, a* and b* differed by up to 1.6, 1.1 and 0.9 units between lamb breeds, while Teixeira et al (2005) reported smaller differences of 0.3, 0.6 and 0.7 units.…”

“…Hopkins and Fogarty (1998) reported that colourimetric measures of meat L*, a* and b* differed by up to 1.6, 1.1 and 0.9 units between lamb breeds, while Teixeira et al (2005) reported smaller differences of 0.3, 0.6 and 0.7 units. Teixiera et al (2005) also reported that lamb live weight within an age range of 90 -120 days had a large effect on L* and b* (5.0, 6.1) though not on a* (1.1), while only small differences in meat L*, a* and b* (1.5, 0.8 and 0.3) were measured between the sexes.…”

Intrinsic factors affecting sheep meat quality: a review

“…Juárez et al (2009) observed an increase (p<0.01) in myoglobin (3.09 to 4.01 mg/g), low (p<0.01) luminosity (45.10 to 40.19 L * ) and increased (p<0.01) redness (7.35 to 9.79 a * ) with increasing (p<0.01) slaughter weight of Grazalema Merino sheep breed. In another study, Teixeira et al (2005) identified a reduction (p<0.05) in L * of 40.0 ± 0.55 to 39.0 ± 0.54 when slaughter weight increased from 9-14 to 19-24 Kg.…”

“…The differences in the degree of muscularity, age and physiological action of the calpain-calpastatin enzyme complex are mainly responsible for the variation in tenderness of lamb meat (Thompson et al, 2006). Teixeira et al (2005) showed objective differences (p<0.01) in meat tenderness between Bragançano (7.8 Kg/cm 2 ) and Mirandesa (6.8 Kg/cm 2 ) sheep breeds. According to the authors, the sensory panel also identified differences (p<0.05) in hardness, assigning scores of 4.1 to Bragançano and just 2.8 for Mirandesa.…”