Sensory evaluation of beef-flavor-intensity, tenderness, and juiciness among major muscles

Twelve muscles from eight USDA Select/Choice grade steers were evaluated for beef-flavor intensity, tenderness, and juiciness. The biceps femoris, psoas major, gluteus medius, semimembranosus, and triceps brachii were similar in beef-flavor-intensity (P > 0·05) and were ranked as the most intensely flavored of all muscles. The rectus femoris, longissimus lumborum, serratus ventralis, infraspinatus, semitendinosus, pectoralis profundus, and supraspinatus generally were less intense in beef-flavor than the other muscles and were ranked from highest to lowest intensity in that order. The psoas major was the most tender (P > 0·05) followed by the infraspinatus, longissimus lumborum, and rectus femoris, which were similar (P > 0·05). Generally, muscles from the chuck and loin were juicier than those from the round.     

Chemical and Sensory Properties of Thirteen Major Beef Muscles

Chemical and sensory properties of the following thirteen muscles from ten Angus steers were evaluated: semimembranosus, semitendinosus, adductor, biceps femoris, rectus femoris, gluteus medius, psoas major, longissimus - loin portion (LD-L), longissimus - rib portion (LD-R), triceps, infraspinatus, pectoral, and supraspinatus. Steaks (3.8 cm) were cooked to 70°C internally on open hearth grills for sensory evaluation. Muscles from the round and chuck, excluding the infraspinatus, were generally scored lower by the sensory panel than muscles from the loin and rib. The psoas major, LD-L, LD-R, and infraspinatus were more tender (P < 0.05) than seven other muscles; WBS values followed the same trend. Large ranges were observed among muscles for percent fat, sarcomere length, and total collagen.     

Body composition of lambs receiving 30 or 60 days of exercise training and (or) fenoterol treatment

The interaction between exercise and the β-adrenergic agonist, fenoterol, on body composition and muscle protein turnover was studied in this investigation. Forty young Hampshire×Rambouillet lambs were assigned to control (CON), exercised (EX), fenoterol-treated (5 ppm) (FEN), or fenoterol-treated and exercised (FENEX) groups. Lambs assigned to the exercise treatments were trained to run on a 10° inclined treadmill. The lambs were slaughtered after 30 or 60 days of treatment. Average daily gain tended (p=0.09) to be greater, and feed:gain was significantly lower (p=0.03) in the EX group than in the FENEX group by 30 days of treatment. By 60 days of treatment, kidney and pelvic fat and bodywall thickness were least in the EX group. Leg weights increased significantly with time only in the FEN and FENEX groups, whereas shoulder weights increased with time in all but the EX group. The latter effect was due to a cessation of adipose tissue growth in the EX lambs. There were significant time×treatment effects for the M. biceps femoris, M. gluteus medius, M. quadriceps femoris, M. semimembranosus, M. semitendinosus, M. infraspinatus, and M. pectoralis profundus. In every case, the time×treatment interaction was caused by nonsignificant growth of muscles in the CON group between 30 and 60 days. For the M. biceps femoris, M. quadriceps femoris, and M. gluteus medius, muscle mass increased with time only in the FENEX lambs. There was no increase in leg subcutaneous or intermuscular adipose tissue mass between 30 and 60 days in the EX lambs, although 50-70% increases in adipose tissue mass were observed over time in the other groups. Calpain and calpastatin activities in M. biceps femoris were not affected by treadmill exercise, fenoterol administration, or time×treatment (p>0.72 for all effects). Myosin light chain-1 gene expression in the FENEX lambs was depressed by 60 d, suggesting that the rate of M. biceps femoris growth in this treatment group was slowing by this time.     

COMPOSITION,WATER-HOLDING CAPACITY AND pH OF MUSCLES FROM PIGS SUPPLEMENTED WITH PORCINE SOMATOTROPIN (pSt)1

Eighteen pigs were injected with one of three levels of recombinant porcine somatotropin (pSt) and received no more injections 7 days before slaughter. Excised triceps brachii, psoas major, semimembranosus, semitendinosus and biceps femoris muscles were analyzed for crude fat, moisture and protein contents, pH and water-holding capacity, Generally, raw muscles from somatotropin-supplemented pigs contained less crude fat than did muscles from control animals. The crude fat content of the broiled triceps brachii and roasted biceps femoris decreased in response to somatotropin supplementation. Muscles from supplemented and unsupplemented pigs did not differ in cooked muscle moisture or protein contents, raw or cooked pH or raw muscle water holding capacity.     

The use of multivariate analysis for evaluating relationships among fat depots in heavy pigs of different genotypes

The aim of the present work was to study distribution and reciprocal relationships of fat depots in heavy pigs of several genetic types. On 161 barrows and gilts belonging to four genetic types (Large White and relative crosses with Italian Landrace, Belgian Landrace and Duroc), slaughtered from 125 to 180 kg l.w., thickness, colour (C.I.E, L*, a*, b*) and weight of backfat and of kidney fat were determined. Subcutaneous and intermuscular fat of ham were weighed. On biceps femoris, semimembranosus and semitendinosus muscles ether extract content was determined. Allometric analysis showed that body growth did not particularly increase the intramuscular fat content of the ham. Principal component analysis indicated that PC1 (0.43% of variation) represented the overall fatness, associated all the depots in a similar manner, and was linked to body weight and sex. PC2 (0.22% of variation), linked to genotypes and body weight, expressed the opposition between intramuscular fat deposition and subcutaneous and internal fat accumulation. Using measurements easily recorded on the side (backfat thickness and colour, percent kidney fat), only the estimate of subcutaneous fat, among ham depots, showed good accuracy (R(2)=0.65).     

A technique for muscle biopsy sampling on pigs to assess intramuscular fat

The objective of the research was to develop a rapid, convenient method for sampling the muscle of live young pigs. A biopsy needle has been developed. It consists of two parts, a hollow outer cylinder and an inner stick. From female piglets (10-25 kg) a biopsy sample of 108 ± 42 mg was taken from the biceps femoris. No infections or mobility problems were observed. The sample can be used for further i.m. fat analysis. The mean fat content in the biceps femoris is 2·24 ± 1·12%. This i.m. fat content was measured by extraction in a Soxhlet apparatus and was determined by a Fourier transform Infrared (FTIR) method. Fatty acid composition was determined by gas-liquid chromatography.     

Instrumental colour of Iberian ham subcutaneous fat and lean (biceps femoris): Influence of crossbreeding and rearing system

The influence of crossbreeding (Iberian vs Iberian×Duroc 50% pigs) and rearing system (Montanera vs Pienso) on the instrumental colour of Iberian ham (subcutaneous fat and biceps femoris muscle) and the relationships to sensory appearance and chemical composition were researched by using a factorial design. In subcutaneous fat, a significant effect (p<0.05) of crossbreeding and rearing system was found: b* and chroma were larger in hams from Iberian pigs than from Iberian×Duroc (50%) pigs, and L*, a* and chroma were larger in Pienso hams than in Montanera hams. CIEL*a*b* variables of subcutaneous fat were closely related to subcutaneous fatty acid composition, the largest correlationships involving L* (L* and 18:0, 0.652, p<0.001; L* and 18:1, -0.616, p<0.001). Instrumental colour variables and sensory appearance were also correlated (L* and fat pinkness, -0.539, p<0.001). In lean (biceps femoris), instrumental colour data was not affected by crossbreeding and rearing system. CIEL*a*b* variables were not related to chemical composition (moisture, NaCl, intramuscular fat and pigment content), although they were correlated to sensory appearance (L* and marbling, 0.419, p=0.014).     

USDA yield grades and various carcass traits as predictors of carcass composition

Twenty-five carcasses from each of three breedtypes (Brahman, Angus and Brahman × Angus) were physically separated into fat, lean and bone. Several muscles from the round and the femur were used to derive equations to predict carcass composition and muscle-to-bone ratio. The femur (as a percentage of the carcass) was shown to predict percentage carcass bone with 90% accuracy. All of the muscles studied were highly related to total carcass lean but the percentage of carcass as M. biceps femoris was the best single muscle indicator of carcass lean of the muscles studied. More variation in carcass lean could be accounted for by a multiple regression equation, involving all four muscles studied, than by any single muscle. M. biceps femoris-to-femur ratio was found to predict carcass muscle-to-bone ratio with a high degree of accuracy. The USDA yield grades were found to be reliable indicators of carcass composition. A two-variable equation involving adjusted fat thickness and biceps femoris accounted for 88·6% of the variation (RSD = 1/·64) in percentage of carcass as separable lean.     

A comparison of distribution and composition of intramuscular fat in Duroc Jersey and Hampshire pigs at 100 kg liveweight

The intramuscular fat content, its fatty acid composition and that from the triglyceride fraction, were determined in several muscles from the right sides of four Duroc Jersey and four Hampshire castrated male pigs slaughtered at 100 kg liveweight. The Hampshires had heavier muscles than the Duroc Jersey pigs, but did not show significant differences in the percentages of intramuscular fat. The concentrations of linoleic acid were, in general, higher in the Hampshire than in the Duroc Jersey pigs and in many muscles the differences were highly significant (p < 0·05) The concentrations of linoleic acid (18:2) in the triglyceride fraction did not differ among muscles within breeds but were higher in Hampshire than in Duroc Jersey pigs.     

Comparative lipid composition of porcine muscles at different anatomical locations

The influence of anatomical location on the intramuscular lipids was studied in Large White pigs. The amount of total, neutral and polar lipids and the composition of fatty acids of the above three fractions were determined for Longissimus dorsi (LD) at two points and Transversus abdominis (TA) and Biceps femoris (BF) taken from the two half carcasses of an animal. The symmetrical samples from the same animal had identical intramuscular lipid characteristics. The three muscles did not show significant differences in their total (2·8 to 2·4g/100g) and neutral (2·1 to 1·4g/100g) lipid contents. The amount of polar lipids was characteristic of every muscle (0·65 g, 0·84 g and 0·97 g per 100 g, respectively, in LD, BF and TA). The fatty acid composition of neutral lipids was influenced by the type of muscle. Polar lipid had similar fatty acid composition in the three muscles. The intramuscular lipids contained appreciable amounts of essential fatty acids of the family n-6; interestingly, a part of which (25% of EFA) was the long chain fatty acid (C20 and C22) located in the polar lipids.     

Ultrasonic characterisation of B. femoris from Iberian pigs of different genetics and feeding systems

Ultrasonic velocity was used to characterise the differences in composition and texture of Biceps Femoris muscles from four batches of pigs of different genetics (Iberian and Iberian × Duroc) and feeding systems ("montanera" and concentrate). Significant differences (p<0.05) were found for the ultrasonic velocity in samples with different genetics and feeding systems. These differences were dependent on the temperature of the measurements and were related to the intramuscular fat content (IMF) of the samples and, therefore, to the meat quality. The ultrasonic velocities at 0 and 20 °C were related to the IMF (R=0.77 and 0.65, respectively). A discriminant analysis, including ultrasonic velocity at temperatures from 0 to 20 °C, allowed 87.0% of the samples to be correctly classified in the batches. Therefore, ultrasonics could be useful in the characterisation and differentiation of B. femoris muscles of Iberian pigs with different genetics and from different feeding systems.     

Comparative study of the histochemical properties, collagen content and architecture of the skeletal muscles of wild boar crossbred pigs and commercial hybrid pigs

The histochemical properties, collagen content and architecture of Musculus longissimusthoracis (LT), Musculus pectoralis profundus (PP) and Musculus biceps femoris (BF) were compared in F(1) (half blood) and F(2) (quarter blood) wild boar crossbred pigs and commercial hybrid pigs, and Japanese wild pigs. F(1) pigs showed the lowest growth rate, followed by F(2) pigs. The most rapid growth was shown by the commercial pigs. The percentage weights of LT and PP muscle to body weight were larger in the wild boar crossbred pigs than commercial pigs. The muscles of the crossbred pigs contained type I and IIA myofibers at higher frequency and type IIB at lower frequency than the commercial pigs, except for LT muscle of F(2) pigs. The myofiber diameter in each type of muscle did not differ between pigs except for the smaller type IIA in BF muscle in commercial pigs. The total amount of intramuscular collagen was less in LT muscles than the others. More intramuscular collagen was found in the wild boar crossbred pigs than the commercial pigs in LT and PP muscles. With an increase of collagen content, the perimysial collagen architecture developed but not the endomysial architecture. Traits characteristic of the crossbred pigs seem to be inherited from the wild boar. Our results clarify that cross breeding with wild boar results in pigs with distinctive muscle characteristics in terms of histochemical properties, collagen content and architecture.     

Pigment oxidation in ground veal: Influence of lipid oxidation, iron and zinc

The color stability of fresh ground veal from four different muscles (biceps femoris, longissimus dorsi, psoas major and supraspinatus) was characterized, and the effects of lipid oxidation, iron and zinc on this degradative process were investigated. Samples were minced and prepared in a manner consistent with retail production and analyzed for pH, myoglobin concentration, total and nonheme iron, and zinc. Pigment and lipid oxidation were measured on days 0, 3 and 6 of 4°C storage. B. femoris demonstrated the greatest extent of lipid oxidation, and was more color-labile than p. major or supraspinatus (P < 0·05), but no different from l. dorsi (P > 0·05). Total iron and myoglobin concentrations were lowest for l. dorsi (P<0·05). Zinc concentration in the four muscles followed the order supraspinatus ? b. femoris ? l. dorsi ? p. major (P < 0·05). Data analysis revealed that initial metmyoglobin formation (days 0 to 3) was significantly correlated with total iron (r = 0·69) or nonheme iron (r = 0·68) in b. femoris, but not any of the other muscles. Correlations between lipid and pigment oxidation in each of the four muscles were performed and the data support a strong relationship between these degradative processes in ground veal.     

Intramuscular fat and muscle fibre lipid contents in halothane-gene-free pigs fed high or low protein diets and its relation to meat quality

Immediately after exsanguination, samples were taken from M. longissimus dorsi (LD) and M. biceps fermorsi (BF) of halothane-gene-free Swedish Yorkshire pigs (entire males and gilts) fed a high-protein (18·5% crude protein, 0·96% lysine; n = 20) or a low-protein diet (13·1% crude protein, 0·64% lysine; n = 20). The lipid content, measured as triglyceride (TG), was analysed after the samples had been freeze-dried and dissected free from blood, fat and connective tissue. Fibre type composition (type I, IIA, IIB, IIC) was analysed by histochemical staining on all samples. In 14 samples of LD, representing the entire variation of the intramuscular fat content (IMF) among the 40 animals, fibre areas, lipid content and oxidative capacity within the fibre types were evaluated. IMF, meat colour and drip loss were measured in both muscles. Shear force was measured on cooked meat samples from LD. IMF was higher in both LD (2·5%) and BF (2·0%) from pigs on the low-protein diet compared with LD (1·5%) and BF (1·3%) from pigs on the high-protein diet. TG content did not differ between diets in BF but was higher in LD from pigs on low- vis-à-vis high protein diet. A significant correlation was seen in LD between IMF and TG content (r = 0·57; P < 0·001). Fibre type composition did not differ between pigs on the two diets. BF had a higher proportion of type I and IIA fibres and a lower proportion of IIB fibres, compared with LD. TG content in muscle was not correlated with fibre type composition or staining intensity for lipids and oxidative capacity. High staining intensity for lipid in LD was seen in all type I fibres and in some type IIA fibres. Meat quality parameters did not differ between groups except shear force, which was higher in pigs fed the high- vis-à-vis low-protein diet (4·7 and 4·0 kg/cm(2), respectively). Shear force was correlated significantly with TG content (r = -0·42; P < 0·01) and IMF (r = -0·43; P < 0·01) in LD. The results of this study show that lipids are stored mainly in type I fibres and in some type IIA fibres. Intracellular triglycerides account for only a small fraction of IMF. The results indicate that IMF and TG content in muscle fibres may be related to shear force.     

Pyridinoline in ovine intramuscular collagen

Pyridinoline, a mature crosslink of collagen, was measured in intramuscular connective tissue isolated from ovine semimembranosus, a muscle noted for its highly insoluble collagen. Concentration ranged between 0·25 and 0·59 mol/mol of collagen, on the high side of concentrations reported in the literature for this and other muscles in various species. Pyridinoline concentration was inversely related to collagen solubility in muscle homogenates (P < 0·0). In a comparison between semimembranosus, biceps femoris and gluteus medius, pyridinoline concentration was again inversely related to collage solubility. For all these muscles, pyridinoline remained insoluble in a heat-dependent solubility test, but it is argued that pyridinoline does not explain all the solubility properties of ovine intramuscular collagen. Pyridinoline concentration was not significantly correlated with sensory or shear properties of cooked semimembranosus, confirming the importance of other heat-stable crosslinks.     

Measurement and prediction of tenderness in six beef muscles

The relationship between subjective and objective evaluations of tenderness and that between the tenderness of different muscles in the same carcass have been examined in six beef muscles whose tenderness had been varied as a result of different post mortem treatments. Panel score (TP) was predicted by 'maximum force' (VF) and 'total work' (VW) on the Volodkevich bite tenderometer in both M. longissimus dorsi and M. semimembranosus (P < 0·001) and the regression coefficients were stable. In M. gluteus medius prediction was less significant (P < 0·01 for VF and P < 0·05 for VW) while in M. psoas major only VW was significant (P < 0·05). In M. biceps femoris and M. semitendinosus no significant prediction was found. These differences between muscles are attributed partly to varying changes in tenderness effected by post mortem treatments and partly to varying connective tissue content. The concept of one muscle acting as an index of toughness in a group of similar carcasses is thought to be untenable.     

Linear hydrocarbons content of intramuscular lipids of dry-cured Iberian ham

This study has been carried out to determine the linear hydrocarbons content (n-alkane and n-alkene) in intramuscular lipids (biceps femoris muscle) of dry-cured Iberian ham considering "feeding system" (Montanera: fed on acorns and pasture and concentrate feed) and "genotype" (hams from Iberian pure pigs and hams from Iberian crossbreed with Duroc in a 50%). The linear hydrocarbons from n-C(14) to n-C(32) range were present in the four studied groups. n-Alkenes fraction (60-76 mg/kg of intramuscular fat) was higher than n-alkanes fraction (34-38 mg/kg). The most abundant n-alkane and n-alkene were the shortest chain ones. Feeding and genotype did not influence linear hydrocarbons content (neither n-alkanes nor n-alkenes).     

Thermal transition of collagen in ovine connective tissues

The thermal transition temperature (T(m)) of collagen in a range of muscle and non-muscle connective tissues from lambs, hoggets and mature sheep was measured by differential scanning calorimetry. The muscles selected were: semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), Longissimus dorsi (LD) and psoas major (PM). Although the T(m) of intramuscular SM collagen from an aged ewe underwent no significant change with time post mortem, that of a 5-months-old lamb had dropped by 0·9°C after 2 days at 19°C. The epimysium of each muscle exhibited a higher T(m) than the corresponding intramuscular connective tissue. The LD and BF tendons each had a lower T(m) than corresponding intramuscular connective tissue but this was not true for the PM. Furthermore, the PM tendon generated an isometric tension more than five times that of the LD, BF or psoas minor tendons. This indicates that the PM tendon is richer in heatstable crosslinks than any of the other tendons investigated. In all tissues, except the liver capsule, there was an increase in T(m) with animal age. However, the rate of change T(m) varied from one tissue to another. For example, the SM intramuscular collagen matured at an earlier age than that of other muscles, the PM being slowest to mature. In keeping with the changes in T(m) values, the Warner-Bratzler peak force of ST muscles increased markedly in older sheep, but there was no significant difference in peak force of SM muscles between lambs, hoggets and mature sheep.     

Variability within intramuscular fat content of pigs as measured by gravimetry, FTIR and NMR spectroscopy

In order to determine in vivo intramuscular fat content of pigs' biceps femoris, three methods were compared. Gravimetry and FTIR spectroscopy after total fat extraction from a biopsy (about 400 mg skeletal muscle tissue) and in vivo ¹H NMR spectroscopy after imaging and volume of interest selection were used. Mean values (g fat/100 g fresh tissue) were, respectively, 1·47 ± 0·35 (gravimetry), 1·26 ± 0·33 (FTIR) and 0·51 ± 0·19 (NMR); but NMR-values represented only triglycerides. Within an intramuscular fat range from 1·1 to 2·7 g per 100 g fresh muscle tissue, possible to estimate a calibration line between the in vitro and in vivo data for hybrid piglets of about 18 kg. Repeated in vivo NMR measurements on the same muscle volume showed a mean coefficient of variation of 5·5 ± 2·7%. The coefficient of variation of measurements on different volumes within the same muscle was 14 ± 10%. The mean intramuscular fat content of 18 kg or 100 kg pigs was, respectively, 1·64 ± 0·46 (biceps femoris) and 1·32 ± 0·1 (longissimus dorsi) g per 100 g fresh muscle tissue.     

Use of the Hennessy Grading Probe (GP) for predicting the meat, fat and bone yields of beef carcasses

Left sides of 36 bulls, 22 cows, 57 steers and 38 heifer carcasses were weighed hot (HCWL) and were probed with the Hennessy Grading Probe (HGP) at five sites to give four subcutaneous fat depths, two M. longissimus dorsi depths and one total tissue depth measurement. A fat depth (GR) over the 10th rib was also measured by ruler probe. The left sides were later separated by knife into saleable eat (90% visual lean), fat trim and bone. Probe readings of subcutaneous fat thickness at the fatter rump sites (BF, 5-7 cm lateral to the perianal region over the M. biceps femoris; SC8, 8 cm lateral to the prominence of the sacral crest) were smaller than ruler measurements at the same sites. Probe eye muscle depth measurements were smaller than measurements taken at the same site by ruler. The BF measurement taken by probe, combined with HCWL, gave the best prediction of percentage fat trim (RSD = 2·0% for steers and 2·2% for heifers) and edible meat yield (RSD = 2·0% for steers and 2·6% for heifers) in the left sides of all the measurements studied, either singly or in combination. A major problem was to find a measurement site where subcutaneous fat was not removed from some carcasses during hide removal.