The relationship of carcass measurements to carcass composition and intramuscular fat in Spanish beef.

Forty beef carcasses were classified for conformation and fatness. Besides, carcass weight, fat thickness (FT), carcass dimension, marbling by computer image analysis and ultrasound readings was recorded to complement grading. For predicting intramuscular fat (IMF) content, FT, number of intramuscular flecks and conformation increased R(2)-value from 0.19 to 0.64 compared to conformation alone. For visual marbling, ultrasound readings and thoracic depth (TD) increased the R(2)-value from 0.24 to 0.57 compared to fatness score (FS). The best variables for predicting weight of fabricated subprimals were carcass weight or compactness which is a function of carcass weight (R(2) between 0.94 and 0.63). Fatness score was poorer than FT for predicting yield of subprimals cuts from round (R(2)=0.16 vs. 0.50) and ultrasound readings for less valuable subprimals (R(2)=0.31 vs. 0.39). These results showed that other variables could be used in combination with carcass fatness or conformation to achieve a more accurate estimation of fat and carcass yield.

The effect of cooking on the fatty acid composition of longissimus muscle from beef heifers fed rations designed to increase the concentration of conjugated linoleic acid in tissue.

Longissimus dorsi (LD) muscle from 60 Charolais crossbred heifers, aged for 14 days was used to investigate the effect of cooking on the content of PUFA and CLA fatty acids. Animals were offered a control diet of grass silage and concentrates (CO) or rations designed to enhance the concentration of CLA in tissue, i.e. unsupplemented grazed pasture (G), sunflower-oil supplemented grazing (SFG) or linseed-oil oil supplemented grazing (LSG). The SFG diet was the most effective for increasing the concentration of CLA but also caused the highest n-6/n-3 fatty acid ratio. There were no changes in the relative distribution of fatty acids upon cooking (140°C for 30min) and this procedure can be recommended because it preserves the nutritional value of the meat. It is concluded that irrespective of the change in the fatty acid composition of LD due to alteration in the diet of the cattle, cooking did not cause thermal degradation of PUFA, or thermal degradation or oxidative synthesis of CLA.

Predicting Longissimusdorsi myoglobin oxidation in aged beef based on early post-mortem colour measurements on the carcass as a colour stability index.

Sixty young bulls of the Pirenaica breed, representative of the beef production and marketing system in northern Spain, were used. The carcass grading and weight, pH at 24h post-mortem, and objective colour measurements (CIE L(∗)a(∗)b(∗)) were recorded on the Latissimus dorsi, Rectus abdominis and Longissimus dorsi in order to find indicators and predictors of beef colour stability (Longissimus dorsi metmyoglobin percentage on ageing for 3, 7 and 14days) by means of early post-mortem measurements on the carcass. Neither the conformation nor the degree of fattening, under the current EU beef carcass classification system, displayed any statistically significant relationship with colour stability of beef aged 3, 7 and 14days. However, there was a relationship between the instrumental colour measured on the carcass and the colour stability of the beef. This relationship allowed prediction of colour stability (Longissimus dorsi MMb percentage) after 3, 7 and 14days of ageing and 48h blooming using colour coordinates measured on the carcass.

Relationship between carcass traits, prime cuts and carcass grading from foals slaughtered at the age of 13 and 26 months and supplemented with standard and linseed-rich feed.

In order to improve foal carcass quality, it is necessary in particular to improve the carcass dressing percentage and tissue composition. Thus, it is important to establish relationships between grading systems and these parameters. This research was conducted to study the effect of slaughter age (13 v. 26 months) and finishing feed (standard v. linseed feed) on carcass characteristics such as subcutaneous fat colour plus classification of foals for the degree of fatness and conformation. For this study, 46 foals of crossbred genotype (Galician Mountain×Burguete) were used. Finishing feed did not affect any parameter, whereas slaughter age influenced all parameters (P<0.05). The oldest foals had higher carcass measurements, 13% more of meat, 4% more of bone, 12% more of fat, and 4% and 9% bigger fore- and hindquarter, respectively. Consequently, bigger valuable prime cuts were obtained. Nevertheless, the meat : bone ratio was very similar for both 13- and 26-month-old foals (2.88). Most of 26-month-old foals were classified in 'E' (Extra) and '5' (Complete fat cover) categories of conformation and degree of fatness. Most of the carcasses showed subcutaneous fat described as yellowish-white irrespective of age or diet. A regression model found that conformation (36%) and degree of fatness (33%) in live animals was positively linked with carcass tissue composition. It is therefore suggested that producers aim for older slaughter ages than 13 months and that the foal meat industry establishes grading systems to predict carcass quality. Further studies should be necessary to find the optimal slaughter age to obtain carcasses in the best categories of degree of fatness and conformation. New studies should be recommended to improve the meat : bone ratio of foal carcasses as it estimates the aptitude for meat production.

Predicting longissimus dorsi texture characteristics in beef based on early post-mortem colour measurements.

Sixty young bulls of Pirenaica breed that were representative of the beef production and marketing systems in Northern Spain were studied. The following parameters were determined with the aim of predicting beef texture characteristics of the longissimus dorsi based on the objective measurements taken on the carcass at the early post-mortem period: colour measurement (CIE L(∗)a(∗)b(∗)) readings were taken on the latissimus dorsi (LTD), rectus abdominis (RA), and longissimus dorsi (LD) muscles. In this study, it was observed that more information on beef tenderness is obtained with colour measurements taken on the carcass LTD and RA, and LD at 24h post-mortem. However, the regression analysis showed that beef TI from Pireanica young bulls can be predicted quite accurately by C(∗) measured on the RA muscle just 45min after slaughter.

Colour and texture characteristics in meat of male and female foals.

The effect of livestock production system and sex was studied on the colour and on the texture profile of the longissimus dorsi muscle (LD) from 16- and 24-month-old foals aged 4 days. Besides, the effect of ageing time was also studied on the texture profile between 4 and 8 days. Females from the 16-months group were darker than their counterparts and the 4-day aged steaks of the 24-month-old foals were lighter, redder and yellower. LD muscle of the 24-month-old foals was tougher after 4 and 8 days ageing than that of the younger foals besides in the 24-month-old foals the toughness may have been accentuated by lower growth rate prior to slaughter. Ageing improved tenderness but the rate of tenderisation was different according to age. The colour coordinates a(∗) and b(∗) could differentiate the 4-day aged steaks of the foal samples according to production system to a higher degree than did the compression or WBSF values being b(∗) values the most important colour coordinate which could discriminate the origin of the animals.

Intramuscular and subcutaneous lipid fatty acid profile composition in male and female foals.

This study characterised the lipid classes of Longissimus dorsi (LD) muscle and the fatty acid profiles of the LD intramuscular fat and subcutaneous (SC) adipose tissue of male and female foal mixed populations. Two animal groups were studied based on slaughter ages of 16 and 24 months. The sex of the animals had no statistical significance in the lipid fractions of the LD muscle or in the intramuscular fatty acids (p⩾0.05). In contrast, there was a significant effect of sex on the fatty acid profile of the SC adipose tissue. Furthermore, the livestock production system showed difference in both lipid class and fatty acid profiles from the LD and SC adipose tissues. The LD of 24-month old foals had lower phospholipids content (p⩽0.001), displayed little difference in saturated fatty acids (SFA) (p⩽0.1), exhibited higher levels of monounsaturated fatty acids (MUFA) (p⩽0.05) and lower levels of polyunsaturated fatty acids (PUFA) (p⩽0.05) compared with that of the 16-month old foals. Furthermore, the fatty acid profile of the SC adipose tissue of the 24-month old foals had higher SFA (p⩽0.05) and PUFA (p⩽0.01) with lower amounts of MUFA (p⩽0.001) relative to the 16-month old foals.

Composition and estimation of intramuscular and subcutaneous fatty acid composition in Spanish young bulls.

Sixty Pirenaica yearling intact bulls were raised and slaughtered at 519±50kg live weight and 371±18 days of age. Fatty acid composition of intramuscular lipids in longissimus dorsi muscle and subcutaneous fat were determined by capillary gas chromatography. Carcass conformation and fatness, carcass weight, ether extractable intramuscular fat percentage, marbling, dorsal fat thickness, and ultrasonic parameters were recorded to study the relationship between these traits and fatty acid profile. Lipids of subcutaneous adipose tissue had higher monounsaturated fatty acids (MUFA) percentage (49% vs. 33%) but lower saturated fatty acids (SFA) (51% vs. 46%) and polyunsaturated fatty acids (PUFA) (16% vs. 5%) percentages than intramuscular fat depots (p<0.001). Fatter carcasses had higher MUFA percentage and lower PUFA percentage (p<0.01) in intramuscular fat. Carcass weight and conformation would contribute to explain the fatty acid profile of subcutaneous fat (p<0.05). Ultrasound readings reflected the effect of fatness on fat composition.

Carcass characteristics and meat quality of male and female foals.

This research was conducted to characterize the carcass traits and meat quality of 16-month and 24-month old foals (33 males and 23 females) reared in two different livestock production systems. The carcass parameters assessed were conformation, degree of fatness, morphology, weight and carcass meat colour. The physicochemical characteristics and sensory profile of the M. longissimus dorsi (LD) were determined at 4 days of ageing. The carcass parameters and meat quality traits differed little between colts and fillies. There were significant differences between production systems. Carcasses were characterized by B conformation, 3 of fatness and high dressing percentages (>63%). Foal meat had a high myoglobin content and there were differences between the production systems in the flavour, juiciness, flourness and greasiness of the LD.

Effect of weight at slaughter on the volatile compounds of cooked beef from Spanish cattle breeds.

The volatile compounds in cooked beef from the local Spanish cattle breeds, Asturiana, Avileña, Parda Alpina, Pirenaica, Retinta, Rubia Gallega, and Morucha, were studied. Bulls were slaughtered at a live weight of 300 and 550kg and the beef was aged for seven days before cooking. Differences in volatile composition among the breeds were considerable and may contribute to the perception of flavour differences in the cooked beef. Peak area values for dimethyl sulfide, which could be related to cauliflower notes, were highest for the meat from the Pirenaica breed. Levels of the detected volatiles, especially sulfur compounds, in the beef from the Asturiana breed were low-intermediate and were potentially related to blood and liver notes and unpleasant flavours. Avileña stood out among the rustic breeds because of its high values for 1-octene, methylcyclohexane, tetradecane and carbon disulfide, while Retinta displayed high 2,3,4-trimethylpentane levels. The effect of weight at slaughter was influenced by breed, because, except for octane, all the volatile compounds behaved differently according to the breed. Ethanol was characteristic of animals with a high percentage intramuscular fat content, and carbon disulfide was characteristic of animals slaughtered at the lower of the two live weights considered.

Occurrence of conjugated linoleic acid in longissimus dorsi muscle of water buffalo (Bubalus bubalis) and zebu-type cattle raised under savannah conditions.

Lipid extracts from longissimus dorsi muscles of 64 water buffaloes and 68 zebu-type cattle were used to quantify the amount (mg/g of lipids) of total conjugated linoleic acid (CLA), CLA isomers c9, t11 and t10, c12 and linoleic acid (LA), according to species (buffaloes and cattle), age (slaughter groups at 7, 17, 19 or 24 months of age) and gender (bulls and steers). The effects of gender and age were significant (P<0.05) but marginal. Comparisons of lipid extracts from buffaloes vs. cattle showed that total CLA (1.83 vs. 1.47 mg/g), CLA c9, t11 (1.27 vs. 1.01 mg/g) and CLA t10, c12 (0.56 vs. 0.47 mg/g) isomers as well as the CLA/LA ratio (0.10 vs. 0.07) were higher (P<0.05) in buffalo lipids. Considering the sparingly low lipid concentrations (<2 g/100 g of fresh muscle) none of the meat species should be considered a significant source of CLA.

Characteristics of Lacha and Rasa Aragonesa lambs slaughtered at three live weights.

A study was made of differences in the quality of meat from Lacha (L) and Rasa Aragonesa (RA) lambs slaughtered at 12, 24, or 36 kg live weight. Lambs from both breeds were weaned at 25 to 57 d, approximately 11.5 to 18.5 kg live weight, and fed concentrate and barley straw until slaughter at 24 and 36 kg live weight. Hot carcass weight, cold carcass weight, conformation, color, firmness, and thickness of backfat and color of rectus abdominis muscle were recorded on the carcass. Final pH (pHu), instrumental color (L*, a*, b*), myoglobin concentration, chemical composition, and water-holding capacity (WHC) of the longissimus muscle, shear force of the biceps femoris muscle, and iodine values and fatty acid composition of the i.m. and s.c. fat depots were determined. The percentage of fat in the longissimus muscle increased with live weight, and values for RA lambs were higher than those for L lambs. The WHC of meat from RA lambs was lower at 24 kg than at 12 or 36 kg slaughter weight. Live weight and breed had no effect on the shear force of the biceps femoris muscle. There was an increase in myoglobin concentration in the longissimus muscle with increased live weight in both breeds. The fatty acid content of s.c. and i.m. fat, which was not affected by breed, declined with the increase in slaughter weight. The polyunsaturated fatty acid content of the s.c. fat depot increased, whereas that of the i.m. fat depot decreased, with the increase in slaughter weight in both breeds. Subcutaneous fat had a higher content of heptadecanoic acid (17:0) than i.m. fat, and this increased with the increase in slaughter weight. In both depots, there was an increase in oleic acid (18:1) at 12 kg in RA lambs and at 24 kg in L lambs. In the s.c. fat depot, there was a progressive increase in linoleic acid (18:2) content with the increase in live weight in both breeds. There was a higher degree of unsaturation in the s.c. fat of RA lambs than in that of L lambs, which was reflected in the iodine value.

Cured colour development during sausage processing.

A study of colour evolution in dry cured sausage manufactured using industrial technology was made. Parameters which define changes related to nitrosation during curing were determined. The main changes in the colour characteristics of Spanish sausage took place during the fermentation stage. pH, nitrate and nitrite concentration, pigment nitrosation index, pigment discoloration index, a(∗), b(∗), C(∗) and H(∗) values decreased during this stage. However, the nitrosation of the myoglobin pigment continued during the whole curing process. The percent conversion of total pigments to the cured nitric oxide heme pigment form was about 70% in the minced mix, and it increased gradually to about 90% in the final product. During fermentation nitrites reacted with myoglobin (Mb) to form nitrosomyoglobin (NOMb) and metmyoglobin (MetMb), which reduced to NOMb during the drying process.

A study of changes in the fat content of some varieties of dry sausage during the curing process.

The influence of the curing of dry sausage (chorizo, saucisson, salami) on the chemical composition of lipids was studied in terms of what affects the oxidation and resulting production of volatile aldehydes, mainly hexanal. Microbial fermentation initially increases the unsaturation, although this phenomenon is reversed during the drying-curing process. In this phase the saturation/unsaturation ratio rises in C16 and C18 fatty acids, the increase being higher in chorizo and lower in salami. Stearic acid appears to increase more than palmitic acid, and C16 quotient values show significant differences across a range of commercially-sold brands of each type of sausage. Unsaturation varies in parallel with the iodine value in the three cases studied. Lipolytic phenomena produce fatty acids with a greater amount of linoleic acid than oleic acid. The oxidation of these fatty acids is progressive regardless of whether TBA or carbonyl values are measured. Nevertheless, significant correlations of hexanal concentrations are not evident. The formation of butanal and pentanal (<2 µmol) is very low, and hexanal concentration fluctuates (11-111 µmol) among commercial brands and types of sausage. These concentrations are always much higher in chorizo samples than in those of salami. Statistical multivariant analysis highlights the greater significant differences in salami samples, a sausage which reflects the lack of homogeneity between different industrial processes.

Technological suitability of mutton for meat cured products.

A comparative study on the technological suitability of mutton and pork for meat cured products was carried out. One type of cured dry sausages was made of mutton and the other of pork, using the same formulation and technological conditions. Thus, the evolution of physico-chemical and microbiological parameters, as well as colour and texture were measured at three different stages of the process: after mincing, after fermentation and after drying. The sensory parameters were assessed in the final product. Both mutton and pork had a similar technological aptitude during processing of cured dry sausages, with a similar evolution of the pH value, a(w) and Lactobacilli counts. The main differences between both types of sausage were observed in texture, colour and in the organoleptic characteristics, having mutton sausages greater cohesivity and more stable and redder colour than pork sausages. Besides, mutton sausages showed an aroma, flavour and texture that were not desirable for the panellists.

Shelf life of beef from local Spanish cattle breeds stored under modified atmosphere.

Beef steaks from six Spanish cattle breeds (Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, Rubia Gallega and Retinta) were packaged under modified atmosphere (60% O(2), 30% CO(2) and 10% N(2)). Water loss, pH, thiobarbituric acid values (TBA), aerobic plate counts, lactic acid bacteria and Enterobacteriaceae counts, CIE L*a*b* colour values and the sensory properties of odour and colour were recorded before packaging (day 0) and after 5, 10 and 15 days of storage. A significant interaction (P<0.05) between breed and storage time was found for all variables, except water loss. Values of pH were between 5.3 and 5.6; maximum water loss (2.64%) was reached after 10 days of storage; aerobic plate counts, lactic acid bacteria and Enterobacteriacea counts were lower than 10(7) CFU/g, and L* increased with storage time while a* decreased (P<0.05). The maximum shelf life of beef assessed by sensory evaluation (regarding colour and odour degradation) was between days 5 and 10 in meat from Retinta breed and between days 10 and 15 in meat from the other breeds, shelf life was probably limited by lipid oxidation.

Lipid composition of the intramuscular fat of beef from Spanish cattle breeds stored under modified atmosphere.

The lipid composition of intramuscular fat from 30 young bulls of 5 Spanish cattle breeds (Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica and Retinta) was studied. Steaks from each shortloin were packaged in 60% O(2), 30% CO(2) and 10% N(2) and aged for 0, 5, 10 and 15 days. Lipid classes obtained by thin layer chromatography and total fatty acids obtained by gas chromatography were evaluated. Meat from Asturiana de los Valles had high PL and C contents, and low TG contents that reflected its low intramuscular percentage content. This breed showed high FFA content that likely originated from lipolysis of PL. The main breed effect was due to the low intramuscular fat content observed in the Asturiana de los Valles. After 5 days, FFA decreased because they were probably transformed into other compounds. The Morucha breed may have a genetic predisposition for depositing MUFA, and the high MUFA and C14:0 values observed in the Morucha breed were likely due to its high intramuscular fat percentage. Regarding fatty acid composition, no "days of storage" effect was observed for any of the studied fatty acids, except for C18:3ω6 that increased during the first 5 days of storage in Asturiana de los Valles. Concerning the fatty acid composition, Asturiana de los Valles had the highest PUFA/SFA ratio, while Parda Alpina and Morucha possessed low ω6/ω3 ratios but high C22:6ω3 contents. Finally, the presence of C22:6ω3 and 15-CH(3)-C16:0 may be related to higher intramuscular fat contents.

Colour stability of beef from different Spanish native cattle breeds stored under vacuum and modified atmosphere.

Beef steaks from five Spanish cattle breeds were submitted to three packaging conditions: (a) 15 days under vacuum, (b) 15 days under modified atmosphere (MAP) (60% O(2), 30% CO(2) and 10% N(2)), and (c) 10 days under vacuum plus 5 days more under MAP. CIE L(∗)a(∗)b(∗) coordinates, chroma (C(∗)) and hue (H(∗)), relative concentration of myoglobin, oxymyoglobin and metmyoglobin at the meat surface and sensory evaluation of colour were determined 0, 5, 10 and 15 days after packaging. Beef under MAP showed higher lightness (L(∗)) and hue (H(∗)) and lower redness (a(∗)) and chroma (C(∗)) than beef under vacuum. Colour of beef under MAP was not acceptable after 15 days of storage, due to the high metmyoglobin concentration. Yellowness (b(∗)) was the indicator of differences due to ageing and differences in colour between breeds were related to L(∗), a(∗) and H(∗) values. Packaging conditions had a greater effect on beef colour than breed, but breed differences might change with packaging atmosphere. Both packaging and breed are major factors in packaged beef quality.

Effect of including linseed in a concentrate fed to young bulls on intramuscular fatty acids and beef color.

The effect of varying concentrate composition to include 5% linseed and 200 IU of vitamin E on the growth performance, fatty acid composition, and muscle color during shelf life was assessed in 46 young Pirenaica bulls finished to two fatness levels. Adding 5% linseed lowered the dressing rate without altering daily gain or carcass classification. It likewise did not alter the total saturated, monounsaturated, or polyunsaturated fatty acids in the intramuscular fat, though the percentage of α-linolenic acid and n-3 fatty acids increased significantly while the n-6 fatty acid to n-3 fatty acid ratio decreased. Higher subcutaneous fat cover depth at slaughter increased the total percentage of oleic acid and monounsaturated fatty acids without affecting the percentage of saturated or polyunsaturated fatty acids. Adding 200 IU of vitamin E in addition to linseed did not alter the color of film-wrapped fresh meat during storage in darkness.

Effect of whole linseed and rumen-protected conjugated linoleic acid enriched diets on feedlot performance, carcass characteristics, and adipose tissue development in young Holstein bulls.

Forty-eight young Holstein bulls (slaughtered at 458.6±9.79 kg body weight) were used to evaluate the effect of whole linseed and conjugated linoleic acid (CLA) supplementation on animal performance, adipose tissue development, and carcass characteristics. The animals were fed with one of four isoenergetic and isoproteic diets: control (0% linseed, 0% CLA), linseed (10% linseed, 0% CLA), CLA (0% linseed, 2% CLA), and linseed plus CLA (10% linseed, 2% CLA). Animal performance and carcass characteristics were unaffected by diet composition. Adding linseed or CLA to the concentrate diet did not result in significant differences in adipocyte size and number or lipogenic enzyme activity. However, while the frequency distribution of subcutaneous adipocyte diameters followed a normal distribution, the frequency distribution of intramuscular adipocyte diameters was not normal in any dietary group (skewness coefficients: 0.8, 1.2, 0.9, 0.8 for control, linseed, CLA, and linseed plus CLA, respectively; P<0.05), indicative of adipocyte proliferation in the intramuscular adipose tissue.