J.L. Olleta

Assessment of breed type and ageing time effects on beef meat quality using two different texture devices

Forty-two male yearlings were used to assess the influence of breed type and ageing time on beef texture. Samples of the M. longissimus dorsi of four breed types [double muscled (DM), dual purpose (Brown Swiss, BS), fast growth (FG) and unimproved type (UT)] were aged for 1, 3, 7, 10, 14 or 21 days at 4°C and frozen at -18°C until analysed. Cooked samples (to end-point of 70°C) were assessed using a Warner-Bratzler (WB) device. Raw samples were assessed using a compression device in which transverse elongation was prevented. There were no significant differences in WB values of cooked meat due to breed type, but ageing had a significant (P<0.05) on maximum load. Ageing, but not breed type, had a significant effect on the compression values of raw meat at low compression rates (P<0.001). Compression values, of raw samples, at 80% compression differed significantly (P<0.001) between breed types, but were not affected by ageing. Compression values of raw samples, at 80% compression, were affected by breed type, probably because of genotype differences in the contribution of connective tissue.

Relationship between collagen characteristics, lipid content and raw and cooked texture of meat from young bulls of fifteen European breeds.

Variations in texture were determined for 10 day aged raw and cooked Longissimus thoracis (LT) muscle from 436 bulls of 15 European cattle breeds slaughtered at an age of 13-16 months. Variations in texture were related to differences in pH 24 h post-mortem, sarcomere length, collagen characteristics and lipid content. The shear force of cooked meat samples varied from 43.8 to 67.4 N/cm². Simmental, Highland and Marchigiana cattle had the highest shear force values and Avileña-Negra Ibérica, Charolais, Casina and Pirenaica cattle had the lowest values. Cooked meat toughness showed a weak negative correlation to lipid content (P<0.001) but no correlation to collagen characteristics. Raw meat texture measured by compression correlated positively (P<0.001) with total and insoluble collagen. In conclusion, collagen characteristics showed correlation to raw meat texture but not to cooked meat toughness of LT muscle in European young bulls.

Breed effect on carcase and meat quality of suckling lambs

The influence of breed on carcase and meat quality traits was studied in 48 suckling lambs (approximately 1 month old) from the Churra, Castellana and Manchega Spanish breeds and Awassi crosses. Carcase quality traits were determined by visual assessment and objective measurements. Meat quality was assessed by instrumental and sensory analysis. Breed effect was significant for fatness, carcase conformation and fat colour (visual indicators); dressing %, carcase weight, carcase length, buttock and chest measurements, and lean and fat proportions in the left half of the carcase. A significant breed effect was observed for some instrumental measurements of meat quality (meat colour and cooking losses), and for some sensorial attributes (tenderness and juiciness). These results suggest that there is a measurable effect of breed on both carcase and meat quality traits in this type of young suckling lamb, owing to differences in precocity and inherent productive capabilities.

Influence of weaning on carcass quality, fatty acid composition and meat quality in intensive lamb production systems

This study investigated the effects of weaning and sex on various aspects of production and quality characteristics in 22 male and 18 female lambs of the Rasa Aragonesa local meat breed. Half the lambs were weaned (W) at 38 to 40 days and half were left unwearied (UW). Both groups were given ad libitum concentrates and cereal straw. Average farm weight was 22·1 kg at 78·3 days. Live-weight gain was significantly different between sexes but not between W and UW lambs. Dressing proportion was higher in UW lambs. Significant differences in fatness were found between W and UW lambs and between sex of lambs. Among the meat quality traits, W lambs had redder and UW lambs paler meat judged by colour a* and haem pigment concentration. No statistical differences were found in the other traits except flavour intensity, which was higher in UW (66·8) than in W (63·6) lambs on a 1 to 100 scale. All other eating quality aspects, in grilled m. longissimus lumborum slices, tended to be higher in UW lambs. The fatty acid composition of subcutaneous and intramuscular fat depots differed significantly (intramuscular fat was more unsaturated and polyunsaturated). There were also differences between W and UW lambs in subcutaneous fat (higher unsaturated in W lambs). However in intramuscular fat composition only differences in polyunsaturated fatty acids (higher in UW lambs), but not in total unsaturated or saturated, were observed. Tatty acids of less than C16 chain length were higher, in both fat depots, in UW lambs than in W lambs reflecting greater incorporation of milk fatty acids. Palatability characteristics were not closely associated with fatty acid composition except that flavour intensity was correlated with total saturated fatty acids.

Near-infrared reflectance spectroscopy for predicting chemical, instrumental and sensory quality of beef.

The aim of this study was to assess near-infrared reflectance (NIR) spectroscopy as a tool for determining sensory and texture characteristics of beef. Chemical, instrumental, texture and sensory characteristics were predicted by near-infrared reflectance spectroscopy carried out on longissimus dorsi muscle samples from 190 young bulls. The use of first derivative gave best predictions together with NIR spectra, except for myoglobin and water holding capacity, which had an R(2) of prediction of 0.91 and 0.82, respectively, using visible and NIR spectra. Tenderness was the best-predicted variable (R(2)=0.98) demonstrating the potential of NIR spectroscopy in the prediction of sensory variables. Chemical composition variables and Warner-Bratzler shear force were predicted with an R(2) of prediction of around 0.7, but protein was not predicted with accuracy.

Eating quality of young bulls from three Spanish beef breed-production systems and its relationships with chemical and instrumental meat quality

Sensory characteristics of longissimus thoracis muscle from three local Spanish beef breed-production systems and their relationships with chemical and instrumental meat quality traits were studied. Young bulls of Bruna dels Pirineus (BP; n=69), Avileña-Negra Ibérica (A-NI; n=70) and Morucha (MO; n=70) breeds were reared in their own production systems. MO breed showed the highest water holding capacity and also the highest thawing loss and haem pigment content (P<0.001). No differences in moisture and protein contents were found among breeds. A-NI showed the highest intramuscular fat (IMF, P<0.05) and total collagen (P<0.001) contents, whereas BP showed the lowest IMF content (P<0.05) and the highest collagen solubility (P<0.001). Beef flavour, tenderness and juiciness accounted for the eating quality differences among the three breed-production systems. Meat from A-NI was rated significantly higher (P<0.01) for beef flavour and tenderness than that from BP and MO animals. Furthermore, MO showed the lowest juiciness (P<0.001) which could be due to its higher thawing loss. Within the three breeds, thawing loss was negatively correlated with juiciness and, likewise cooking loss with juiciness and tenderness (P<0.05). The canonical discriminant analysis showed that the three breeds were significantly different (P<0.05) from each other according to sensory attributes, which justifies their involvement in different protected geographical indications (PGI).

Carcass characterisation of seven Spanish beef breeds slaughtered at two commercial weights

A total of 159 bulls representing seven Spanish beef breeds were fed with concentrates, managed in the same conditions and slaughtered at two commercial weights (veal and young-bull). Carcasses were measured and classified in order to characterise the carcass variation in the Spanish beef market and to assess the relationship among carcass measurements and grading. Principal Component Analysis clearly separated commercial types regardless the inclusion of the carcass weight in the input data. Within commercial weights the studied breeds clustered into three groups according to muscular development and carcass classification score: high meat producer breeds (Asturiana de los Valles and Rubia Gallega); medium meat producers (Parda Alpina and Pirenaica); and low meat producers (Avileña, Retinta and Morucha). The perimeter and width of the leg (muscular development) besides the length and width of the carcass basically defined these three carcass types. Conformation was an important trait in explaining variation between breeds because its values were positively correlated with muscular development and carcass compactness.

The effect of breed-production systems on the myosin heavy chain 1, the biochemical characteristics and the colour variables of Longissimus thoracis from seven Spanish beef cattle breeds

The effect of breed-production system on the myosin heavy chain 1 (MHC-I), the biochemical characteristics and the colour variables of longissimus thoracis (LT) from seven beef breeds was studied: Asturiana de la Montaña (AM), Asturiana de los Valles (AV), Avileña-Negra Ibérica (A-NI), Bruna dels Pirineus (BP), Morucha (MO), Pirenaica (PI) and Retinta (RE) (Age at slaughter between 368 and 541 days; carcass weight between 249 and 334 kg). Significant differences between breed-production systems were found for all traits evaluated. LT from the MO, a rustic type breed, was the most oxidative (MHC-I, 39.3%; isocitrate dehydrogenase activity, 52 nmol min(-1) mg(-1); pigment content, 188.4 μg acid haematin g(-1)) and showed a low L* value (32.6) and high a* and C* values (24 and 27.2, respectively). In terms of meat colour (L* and a*) the canonical discriminant analysis separated the breeds into two groups, the AV, the PI and the A-NI (the lightest ones) from the AM and the MO breeds (the reddest and darkest) whereas the BP showed an intermediate position. The RE and the A-NI were distinguished from the others by their high intramuscular fat content. Meat colour was affected by the muscle biochemical traits in the breed-production systems studied.

Effect of transport time and ageing on aspects of beef quality

Forty-eight bulls were transported by road in groups of eight for approximately 30 min, 3 or 6 h in two replicates. After slaughter, steaks from the longissimus dorsi thoracis of all transported animals were analysed in terms of pH, water-holding capacity, myoglobin concentration, texture at 7 and 14 days of ageing (compression and Warner-Bratzler analyses) and colour of the same surface of meat cut at 24 h post-mortem and allowed to bloom for 24 h and 7 d (L(∗)a(∗)b(∗), chroma and hue). The myofibrillar resistance of the meat from animals transported 30 min was significantly greater at 20% compression (P<0.05). The maximum load and a(∗)b(∗) and chroma were all lower for meat aged 14 days.

Effect of the pre-slaughter logistic chain on meat quality of lambs.

A total of 144 lambs were sampled in a 3×2×2 factorial design, testing three residence (stay) times at a pre-slaughter classification centre (0, 7, and 28days) and two seasons (summer and winter), with two replicates in each season. Meat from the longissimus dorsi was analysed in terms of pH, WHC, texture, colour (L∗a∗b∗, chroma and hue) and carcass bruising. Stay time had a significant effect (p<0.001) on meat texture, while season had a significant effect (p<0.001) on all variables analysed. Overall, stay time had less effect on meat quality than season and the interaction between treatments was not significant. Meat from lambs slaughtered in winter had some dark-cutting characteristics, with darker colour, higher ultimate pH, tougher meat and lower press juice. In conclusion, pre-slaughter classification and season are sources of stress for lambs and affect meat quality traits.