G. Ripoll

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.

Meat and fat colour as a tool to trace grass-feeding systems in light lamb production.

Ninety-five lambs were fed as follows: lambs and dams grazing alfalfa (Gr); As Gr but lambs had access to concentrate (Gr+S); ewes grazed and lambs received milk and concentrate until weaning and thereafter concentrate and straw (Rat-Gr); ewes and lambs were stall-fed (Ind). Lambs were slaughtered at 22-24 kg of live-weight and fat and M. rectus abdominis colour measured. Visual appraisal scores of Gr and Ind were significantly different. The absolute value of the integral of the translated spectrum (SUM) was greater in Gr and GR+S. A discriminate analysis was able to discriminate between grass-fed and indoor-fed lambs. A logistic regression including SUM and b(∗) classify correctly 99.1% of carcasses. A equation is proposed to calculate the probability of one carcass to do not belongs to Gr or Gr+S group (PNA): [Formula: see text] .

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.

Influence of feeding systems on cortisol levels, fat colour and instrumental meat quality in light lambs

Forty-eight lambs were fed as follows: GR, lambs and dams grazed perennial pasture; GR+S, the same as GR except that lambs had access to concentrate; DRL-GRE, lambs in drylot and dams in rationed grazing; DRL, lambs with dams were stall-fed. DRL-GRE and DRL lambs were weaned at 45days of age. Lambs were slaughtered when they reached 22-24kg of live weight. Plasma cortisol concentration was determined three times before slaughter. Subcutaneous fat and meat colour, and texture were analysed. The different levels of cortisol did not affect meat quality. Both grazing systems gave yellower subcutaneous fat and redder muscles than drylot lambs. Differences between systems relating to colour and texture of the meat disappeared with ageing time, which supports the idea that grazing systems are a good alternative in order to offer similar meat to that coming from drylot systems to which consumers are accustomed. Subcutaneous fat colour was a suitable method to discriminate between grazing and drylot systems, but not within them.

Lucerne grazing compared with concentrate-feeding slightly modifies carcase and meat quality of young bulls

Carcase and meat quality of young bulls raised on one of three fattening strategies from 224 to 450 kg were compared. One group was fed concentrates (CON), another group grazed on lucerne plus 1.8 kg DM barley/day (LUC) and the last group had the same management as LUC young bulls for 3 months and was then finished on concentrates for 2 months. Among carcase traits, only tissue composition differed, with LUC young bulls having more muscle and less subcutaneous and intermuscular fat than their counterparts. Concerning meat quality, most attributes did not differ among fattening strategies but LUC young bulls had the lowest intramuscular fat, which presented greatest n-3 PUFA content. It can be concluded that lucerne grazing can be a good alternative to concentrates for young bulls, with similar carcase and meat quality but with lower fat content and healthier fatty acid composition than young bulls fed concentrates during the finishing period.

Effects of finishing period length with vitamin E supplementation and alfalfa grazing on carcass color and the evolution of meat color and the lipid oxidation of light lambs.

Indoor-kept concentrate-fed light lambs (n=54) were supplemented with 500 mg of dl-α-tocopheryl acetate/kg concentrate for 0, 10, 20 and 30 d before slaughtering at 22-24 kg BW. Simultaneously, 8 lambs with their dams were alfalfa-grazed and the lambs were slaughtered at the same weight. The age at slaughter and carcass characteristics were more affected by grazing than by supplementation with α-tocopherol. The grazing lambs had similar α-tocopherol levels to the lambs fed concentrate with dl-α-tocopheryl acetate for 10 days before slaughter. The length of the feeding period affected the evolution of the color, delaying the blooming and discoloration of the meat. Feeding lambs α-tocopherol enriched concentrate during the last 10 days of life or grazing them on alfalfa drastically diminished the lipid oxidation of the meat. Alfalfa grazing is a feasible alternative to increase light lamb meat shelf life without using additives.

Influence of alfalfa grazing-based feeding systems on carcass fat colour and meat quality of light lambs

One hundred and twenty-seven lambs were fed as follows: lambs and dams grazing alfalfa (Gr); the same as Gr but lambs had access to concentrate (Gr + S); ewes grazed and lambs received milk and concentrate until weaning and thereafter concentrate and straw (Rat-Gr); ewes and lambs were stall-fed (Ind). Lambs were slaughtered at 22-24 kg live weight and fat and M. rectus abdominis colour was measured instrumentally and subjectively. The evolution of the instrumental colour and texture of M. longissimus lumborum was also recorded. There were significant differences in the instrumental colour of subcutaneous fat amongst feeding systems, but no differences were observed upon visual appraisal. On average, M. rectus abdominis colour in the four feeding systems was classed as pink. Differences in longissimus thoracis colour at 0 h disappeared at 24h of air exposure and there were no differences in pH or cooking losses. At no time were any differences in instrumental texture found.

Estimation of light lamb carcass composition by in vivo real-time ultrasonography at four anatomical locations

The objectives of this study were to study the relationship between in vivo ultrasound measurements and cold carcass measurements at 4 anatomical points of the backbone, and to establish regression equations to estimate carcass composition within the cold carcass weight range for Ternasco lambs (8 to 12.5 kg) by using ultrasonic measurements taken at a single location. Measurements of subcutaneous fat and skin thickness and of muscle depth and width were taken over the 10th to 11th and 12th to 13th thoracic vertebrae and the 1st to 2nd and 3rd to 4th lumbar vertebrae. These measurements were taken at 2 and 4 cm from the nearest end of the LM to the backbone and at 1/3 of the LM width with the probe perpendicular to and parallel to the backbone. The left sides of the carcasses were dissected into muscle, fat, and bone. Body weight (22.6 kg) and cold carcass weight (10.8 kg) were representative of Ternasco light lambs. Muscle depth measured at 2 cm, 4 cm, and 1/3 of LM width remained regular, with slight ups and downs along the spine. All the pairs of in vivo ultrasound and cold carcass measurements were significantly different (P<0.05) and had small correlations. All the ultrasound measurements of muscle depth at any location or at any distance to the backbone were less than their equivalent cold carcass measurements, with differences ranging from 0.8 to 5.9 mm. Differences between ultrasound fat thickness + interface (US_FDGI) and cold carcass fat thickness were less than differences between ultrasound fat thickness and cold carcass fat thickness, ranging from -0.9 to -1.0 mm for the former and from -2.1 to -0.5 mm for the latter. The small differences in absolute values between US_FDGI and cold carcass fat thickness suggest that US_FDGI is the best measure of the real fatness level of the lambs. The best prediction equations for muscle, bone, and fat were developed with in vivo ultrasound data measured at the 1st to 2nd lumbar vertebrae perpendicularly to the backbone, but they had limited predictive value. To predict the muscle content of carcass, BW and muscle depth were included, and they explained 59% of variation. Fifty-one percent of total fat was predicted by BW and fat thickness, whereas only 17% of the variation in bone was predicted by 2 fat-related variables. The BW of lambs was an important predictor to improve regression equations but ultrasound measurements were the most important variables when a narrow range of BW was used.

Instrumental meat quality of veal calves reared under three management systems and color evolution of meat stored in three packaging systems.

This study evaluated the meat quality of grazing suckling calves (GR), suckling plus supplemented calves (SUP) and weaned calves finished on concentrates (FIN) and the color evolution of meat packaged in film (FILM), modified atmosphere packaging (MAP) and vacuum packaging (VAC). Intramuscular fat was quite low for all treatments and GR meat had greater percentages of PUFA and lower SFA, MUFA and n6/n3 than SUP and FIN. FIN and SUP meat had more L* and was more tender when aged than GR. GR meat was tough and dark. The packaging system was more influential on meat color than the feeding management. VAC had the lowest values of metmyoglobin when aged. MAP had the greatest L* and hue angle and the lowest redness after 13 d of aging, thus MAP was the packaging with the shortest shelf life.

Estimation of carcass composition by ultrasound measurements in 4 anatomical locations of 3 commercial categories of lamb

The objectives were to study the relationship between in vivo ultrasound measurements and cold carcass measurements at 4 anatomical points along the backbone of lambs and to determine appropriate regression equations to estimate carcass composition by using ultrasonic measurements at each anatomical point. The lambs (n = 114) used were suckling lambs (BW = 11.09 kg), light lambs (BW = 22.43 kg), and wethers (BW = 32.03 kg), representing a wide range of BW. Measurements of subcutaneous fat and skin thickness and of muscle depth and muscle width were taken over the 10th to 11th and 12th to 13th thoracic vertebrae and over the first to second and third to fourth lumbar vertebrae. These measurements were taken at one-third of the musculus longissimus thoracis et lumborum (LMT) width with the probe perpendicular to the backbone. The left sides of the carcasses were dissected into muscle, fat, and bone. The weight of lean tissue increased (P < 0.001) at a rate of approximately 500 g for each kilogram of carcass weight increase. Pelvic fat weight increased (P < 0.001) slightly with increasing carcass weight (11.8 g), whereas kidney fat and subcutaneous fat showed great gains (P < 0.001; 40.3 and 134.4 g, respectively). Ultrasound LMT width of light lambs remained constant along the backbone, whereas LMT width of suckling lambs and wethers increased (P < 0.001) from the cranial to the caudal direction. Ultrasound LMT depth and fat thickness between the 10th and 11th thoracic vertebrae were greater (P < 0.01) than measurements taken at other backbone locations. The greatest difference between ultrasound and carcass measurements was in LMT width, with differences between ultrasound and carcass measurements always being greater in LMT depth than in fat thickness. Carcass LMT width was more closely correlated with carcass lean than with other tissues, especially at both thoracic locations (r = 0.80 and r = 0.71). In general, skin thickness measured by ultrasound was poorly correlated (from r = 0.19 to r = 0.33) with all carcass tissues because of slight variations in skin thickness. Ultrasound LMT depth was more closely correlated with carcass tissues than was carcass LMT depth (from r = 0.53 for bone to r = 0.71 for lean), whereas ultrasound fat depth and carcass fat depth presented similar correlations (from r = 0.49 for bone to r = 0.72 for intermuscular fat). Regression coefficients for predicting lean were 0.95 to 0.96, for predicting subcutaneous fat were 0.67 to 0.75, for predicting intermuscular fat were 0.81 to 0.84, and for predicting bone were 0.78 to 0.88. This study was not conclusive regarding predicting carcass composition in relation to an optimal anatomical position, given that all the anatomical locations studied allowed accurate regression equations. Body weight was the most important predictor of carcass composition, with a slight improvement in regression equations when using ultrasound. However, ultrasound muscle and fat depths were correlated with carcass muscle and fat depths and with the tissular composition of carcass.