Characterization of Longissimus thoracis, Semitendinosus and Masseter muscles and relationships with technological quality in pigs. 2. Composition of muscles

The composition of three porcine muscles (Longissimus thoracis: LT, Semitendinosus: ST, Masseter: MS) was characterized and its link with muscle quality was evaluated. The LT muscle had a higher content of tyrosine, tryptophan, and carbohydrates and a lower content of vitamin E and haem iron than the MS muscle, while the ST had similar composition to MS but a lower content of haem iron. Large differences between muscles were observed in relative amounts of most of the major fatty acids. The LT muscle had higher saturated fatty acids (SFA) and n− 6:n− 3 fatty acid ratio, and lower polyunsaturated fatty acids (PUFA), PUFA:SFA ratio, unsaturation index and average fatty acid chain length than the ST and MS muscles. Muscle pH, redness and chroma were positively correlated with vitamin E and unsaturated lipids and negatively correlated with tyrosine, tryptophan, carbohydrates and saturated lipids, whereas muscle lightness and expressible juice showed similar correlations but an opposite sign with these variables.     

The relationship between muscle fiber characteristics and meat quality traits of highly marbled Hanwoo (Korean native cattle) steers

To investigate the relationships between muscle fiber characteristics and meat quality traits of Korean native cattle, Hanwoo, Longissimus dorsi (LD), Psoas major (PM) and Semimembranosus (SM) muscles obtained from 18 Hanwoo steers and the muscle fiber characteristics were measured by histochemical analysis. Fiber number, area percentages and density of type IIA and IIB were lower in SM muscle, but higher in PM muscle than other muscles. LD muscle had higher pH_24h, L^? value and fat content whereas SM muscle had lower L^? value and fat content. The lowest WBSF with longer sarcomere length was observed in PM muscle, while SM muscle showed the highest WBSF with shorter sarcomere length. Consequently, the percentage of type I and IIB were highly correlated with meat quality traits and inversely correlated with fat content, L^? value and WBSF. Fiber number and area percentage of type I had a positive correlation with fat content and L^? value and a negative correlation with WBSF. These results suggest that Hanwoo steers had high marbling, more lightness and tenderness when the percentage of type I was high and the percentage of type IIB was low in muscle.     

Relationship of Carcass Weight to Muscle Fiber Characteristics and Pork Quality of Crossbred (Korean Native Black Pig × Landrace) F2 Pigs

A total of 168 carcasses of crossbred (Korean native black pig × Landrace) F₂ pigs were divided into four carcass weight groups (A, 70–79 kg; B, 80–89 kg; C, 90–99 kg; D, 100–109 kg). The influence of carcass weight on muscle fiber characteristics and meat quality traits of pork, from the longissimus dorsi, were investigated. Carcass traits such as loin-eye area and back-fat thickness were found to increase with increasing carcass weight. Fat content, sarcomere length, drip loss, and meat color values (L*, a*, and b*) also increased with increasing carcass weight. However, moisture content and Warner–Bratzler shear force decreased with increasing carcass weight. A decrease in the compositions of type I and IIA fibers and an increase in the composition of type IIB fibers were observed with increasing carcass weight. The heavier carcasses showed type I and IIB fibers of bigger size and a smaller size of type IIA fibers. Fiber number percentage and the diameter of type IIB showed a significant positive correlation with carcass weight, fat content, and lightness (p?<?0.05). Fiber diameter of type IIB was positively correlated with loin-eye area, but was negatively correlated with moisture content. However, muscle fiber characteristics had no correlation with back-fat thickness, ultimate pH, Warner–Bratzler shear force, and b* value. In conclusion, crossbred pig which has of high composition and size of type IIB has high lightness (L* value) and water-holding capacity (drip loss). Therefore, excessively high weight of carcass has influence on pale and exudative properties in pig because of muscle fiber characteristics, especially type IIB fiber.     

Effect of low voltage electrical stimulation on biochemical and quality characteristics of Longissimus thoracis muscle from one-humped Camel (Camelus dromedaries)

The effects of electrical stimulation (90 V) 20 min post mortem on meat quality and muscle fibre types of four age group camels (1–3, 4–6, 7–9, 10–12 years) camels were assessed. Quality of the Longissimus thoracis at 1 and 7 days post mortem ageing was evaluated using shear force, pH, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and L^∗, a^∗, b^∗ colour values. Age of camel and electrical stimulation had a significant effect on meat quality of L. thoracis. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in muscle during the first 24 h after slaughter. Muscles from electrically-stimulated carcasses had significantly (P < 0.05) lower pH values, longer sarcomeres, lower shear force value, higher expressed juice and myofibrillar fragmentation index than those from non-stimulated ones. Electrically-stimulated meat was significantly (P < 0.05) lighter in colour than non-stimulated based on L^∗ value. Muscles of 1–3 year camels had a significantly (P < 0.05) lower shear force value, and pH, but longer sarcomere, and higher myofibrillar fragmentation index, expressed juice, and lightness colour (L^∗) than those of the 10–12 years camels. The proportions of Type I, Type IIA and Type IIB were 25.0, 41.1 and 33.6%, respectively were found in camel meat. Muscle samples from 1–3 year camels had significantly (P < 0.05) higher Type I and lower Type IIB fibres compared to those from 10–12 year camel samples. These results indicated that age and ES had a significant effect on camel meat quality.     

Shelf life of case-ready beef steaks (Semitendinosus muscle) stored in oxygen-depleted master bag system with oxygen scavengers and CO2/N2 modified atmosphere packaging

This study aims to evaluate the stability of beef from Semitendinosus muscle packaged in oxygen permeable wrapped-tray units and stored in a master bag system, with and without oxygen scavengers. Changes in the atmosphere composition, microbiological indexes, myoglobin forms and color parameters were monitored during the storage in master bag, blooming and display life. The presence of scavengers reduced rapidly the oxygen concentration and maintained it at values not detectable instrumentally. Within few days of storage in master bags, the resolution of the transient discoloration was completed and the meat quality was maintained over the anoxic storage. After the removal from master bags meat bloomed completely reaching OxyMb level and Chroma values higher than those on fresh meat at t₀. During 48 h of display life at 4 °C, quality attributes had a decay slower than samples stored traditionally in air. Without scavengers the oxygen caused the irreversible discoloration within 7 days, due to the formation of metmyoglobin on the surface.     

Histochemical properties of fibre types in muscles of wild and domestic pigs and the effect of growth rate on muscle fibre properties

This study reports the results of a comparison of the histochemical properties of various types of porcine muscles in wild and domestic pigs. In domestic pigs, the influence of growth rates on these properties were studied in five muscles: longissimus dorsi (LD), semimembranosus (SM), gluteus superficialis (GS), infra spinam (IS) and masseter (MAS). The growth rate was expressed as: (i) live weight (LW) at 165±2 days and (ii) daily LW gain from day 88 to day 165 (DG) on the experimental diet. LD, SM, GS and IS of wild pigs were found to contain a higher area percentage of oxidative type IIA fibres (type IIA%(area)) and a lower percentage area of glycolytic type IIB fibres (type IIB%(area)) than the same muscles of domestic pigs. The capillary density in the light muscles (LD, SM, GS) of wild pigs was twice that of domestic pigs, indicating higher oxidative capacity. In domestic pigs the cross sectional area of type IIB fibres (CSA(IIB)) was markedly larger than the cross sectional area of type I (CSA(I)) and IIA (CSA(IIA)) fibres. The average fibre cross sectional area (CSA(fibre)) was about the same in the muscles of wild and domestic pigs except in LD and SM, where the average fibre cross sectional area was approximately 25% smaller in wild pigs than in domestic pigs. This difference was caused by the large cross sectional area of type IIB fibres in the light muscles of domestic pigs. In the light muscles of domestic pigs, the cross sectional area of type IIA fibres increased most with increasing growth rate. Growth rate influences muscle fibre properties only in light muscles, not in dark muscles.     

Relationship between histochemical, structural characteristics and oxidative stability of rhea limb muscles

Histochemical and structural characteristics were investigated in Gastrocnemius pars interna (GN) and Iliofiburalis (IF) limb muscles of Rhea americana. The average myofibre area cross-section was greater in GN than IF muscle (p < 0.001), whereas the fibre density per section was higher in IF than GN muscle. The only type of myofibre found in both the rhea limb muscles analysed in this study was fast-twitch oxidative-glycolytic fibres (FOG). Immunolabelling analysis and ultrastructural observation of myofibres confirmed the contractile and metabolic characteristics of rhea myofibres, revealing the absolute fast isoform of myosin heavy chain and the abundance of glycogen and mitochondria inside the cells, mainly in IF muscle. These findings converged with previous results on the biochemical and physicochemical characteristics of rhea meat to provide further evidence that myofibre composition substantially influences the oxidative reactions of the muscle and therefore the meat quality, but more in-depth examination is needed to establish the links between myofibre characteristics, myofibre glycogen concentration and meat stability during storage.     

Effects of carcass weight and muscle on texture, structure and myofibre characteristics of wild boar meat

Texture, histology and muscle fibre characteristic of selected muscles: m. quadriceps femoris (QF), m. biceps femoris (BF), and m. semimembranosus (SM) of wild boars of different carcass weight (20±2 and 60±3kgSD) were compared. Muscle texture (hardness, cohesiveness, springiness, chewiness) was determined with the double penetration test performed with the Instron 1140 apparatus. Structural elements (muscle fibre cross-section area, perimysium and endomysium thickness) and percentage of myofibres of each type: I (slow oxidative), IIA (fast oxidative-glycolytic) and IIB (fast glycolytic) per muscle fibre bundle, were measured in muscle samples using a computer image analysis program. The young wild boar muscles showed significantly lower values for the textural parameters (p<0.05). The muscle fibre cross-sectional areas of the juvenile wild boar muscles were significantly lower and the perimysium and endomysium thinner (p<0.05) than those in the old wild boar meat, while the percentage of type IIB fibres was higher. Of all the wild boar muscles tested, the highest hardness and chewiness values were found in BF which, at the same time, showed the highest fibre cross-sectional area and the thickest perimysium and endomysium. The highest percentage of I and IIA fibre types was typical of BF and SM either in young or in old wild boars with the lowest percentage of type I and the highest percentage of type IIB fibres being found in the QF. The results suggest that a higher hardness of wild boar muscles can be connected with a thicker perimysium and endomysium, fibres of higher cross-sectional area and probably a higher content of red fibres (type I).     

Muscle glycogen depletion pattern in halothane-gene-free pigs at slaughter and its relation to meat quality

Muscle fibre type composition and glycogen depletion pattern at slaughter as related to meat quality, were studied in M. longissimus dorsi of halothane-gene-free Swedish Yorkshire pigs fed a high (n=19; 10 entire males and 9 gilts) or a low (n=18; 10 entire males and 8 gilts) protein diet. The muscle consisted of, on average, 8% type I, 9% type IIA and 83% type IIB fibres. Muscle fibre areas were significantly smaller in entire male pigs than in gilts irrespective of fibre type. There were no marked differences in muscle characteristics between pigs fed the low and high protein diets. Low glycogen concentrations were found in most type I and type IIA muscle fibres, while a greater variation in glycogen content was evident in type IIB fibres. The pigs were divided into two groups according to the proportion of glycogen depleted IIB fibres (more or less than 30% depleted IIB fibres). In the group where 30% or more of the type IIB fibres were glycogen depleted, a tendency toward DFD meat (dry, firm, dark) was seen, as the meat had higher ultimate pH (5·62 vs 5·52; p=0·02), lower drip loss (2·7% vs 4·4%; p=0·007) and lower reflectance value (darker meat; 16·5 vs 20·6 EEL units; p=0·0005), compared with the group with less than 30% depleted IIB fibres. No difference in total glycogen content was found between these two groups. This indicates that the distribution of glycogen in different fibre types seems to be of importance for the ultimate meat quality.     

Further studies on bovine muscle composition

The average occurrences of fibre types, I,IIA and IIB in the longissimus dorsi (LD) of female cattle were 18%, 59% and 23%, respectively. The IIB occurrence lay between that for bulls and steers, reported in Young & Bass (1984). Since IIB fibres were absent from the splenius (Sp) of females, its composition was more akin to that of bulls than steers. However, the relative area of I and IIA fibres in female Sp was more like that of steers than bulls since IIA fibres were not disproportionately large in females. Evidence suggests that the occurrence of type I (or II) fibres in the LD is rather static and that changes in the occurrence of IIA fibres, reciprocal to IIB, are more common, irrespective of sexual status-bull, steer or female. The route by which IIA and IIB fibres interconvert is discussed. In animals where both the LD and Sp were sampled, the fibre composition of one muscle was a poor predictor of the other's composition. The correlation between the occurrence of I fibres in Sp and succinate dehydrogenese activity in whole muscle was poor, and reasons are advanced to explain this unexpected result. When dark-cutting muscles were excluded from analysis, the average ultimate pH of LD muscles was lower than that of Sp. This result was consistent with the higher type II fibre content of the LD. Ultimate pH of Sp muscles was correlated with occurrence of I fibres, but in the LD a similar relationship could not be established. A link between occurrence of IIB fibres and proneness to the dark-cutting condition is suggested.     

Studies on use of Enteromorpha in snack food

Seaweeds, also known as sea vegetables, are of nutritional interest, as they are rich in vitamins, minerals and dietary fiber. Enteromorpha compressa (Linnaeus), green seaweed (chlorophyta), which is a rich source of iron and dietary fibre was used as an ingredient in the preparation of Pakoda, a common traditional snack food in India. Pakoda samples showed increases in ash, protein and total dietary fibre contents with increase in Enteromorpha level, accompanied by a nearly fivefold increase in iron content (26.4–126 mg/100 g) and fourfold increase in calcium content (30.1–124 mg/100 g). Bioavailability of iron in Enteromorpha, and Pakoda containing 7.5% of Enteromorpha, did not show any difference (55–56%) at pH 7.5 (intestinal condition). But, at pH 1.35 (gastric condition) the bioavailability of iron in Pakoda containing Enteromorpha was found to be slightly higher (27.1%) than that in Enteromorpha. Reducing power (155–222 μg/g) increased as the Enteromorpha level increased from 0% to 15%. But the addition of Enteromorpha was found to decrease free radical-scavenging activity and the total phenol content. Pakoda containing up to 7.5% of Enteromorpha was found to have a sensory quality comparable with that of Pakoda without Enteromorpha.     

Muscle fiber and fatty acid profiles of Mertolenga-PDO meat

The influence of phenotype and muscle type on intramuscular total lipids (ITL) neutral lipid (NL) and phospholipid (PL) compositions, cholesterol, α-tocopherol and haem iron contents were evaluated in Semitendinosus (St), Longissimus dorsi (Ld) and Supraspinatus (Ss) muscles from 39 Mertolenga young bulls. The results showed that lipid, α-tocopherol, cholesterol and haemic iron contents were not influenced by phenotype. Furthermore, the individual effect of phenotype was not a significant source of variation on ITL, NL and PL fatty acid composition. Muscle histological traits from Unicolor phenotype (n = 13) showed that Ss and Ld muscles exhibited higher proportion of type I (P < 0.001) and oxidative fibers (P < 0.001) and lower percentages of IIB fibers (P < 0.001) than St. The Ss muscle, with higher relative area occupied by oxidative fibers (P < 0.05–0.001) than Ld and St, had higher ITL (P < 0.001), NL (P < 0.001), PL (P < 0.05–0.01), α-tocopherol (P < 0.001), cholesterol (P < 0.01) and haem iron (P < 0.001) contents than its counterparts. Muscle type notably affected ITL, as a result of its influence on NL rather than in PL composition.     

Effect of production system on physical–chemical,antioxidant and fatty acids composition of Longissimus dorsi and Serratus ventralis muscles from Iberian pig

The effect of three production systems of Iberian pigs namely Montanera (free-range system and feeding based on acorns and grass), Recebo (free-range system and nutrition based in combination of acorns, grass and mixed feeds) and Intensive (confinement with mixed feeds) on some quality traits of Longissimus dorsi (LD) and Serratus ventralis (SV) muscles were studied. Muscles from pigs raised in the Montanera system showed significantly higher CIE L^∗, a^∗ and b^∗ values and higher haem pigment content than those from Intensive system. Similarly, muscles from pigs raised in the Montanera system had significantly higher contents of α and γ-tocopherol and phenolic compounds contents and higher lipophilic and hydrophilic activity antioxidant than those from pigs raised in the Intensive system. Fatty acids profiles from Montanera pigs had significantly higher monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids and lower saturated fatty acids (SFA) than those from pigs raised in the Intensive system. In relation to muscle effect, LD showed lower intramuscular fat (IMF), α-tocopherol, phenolic compounds, lipid oxidation and PUFA, but higher MUFA than SV.     

Effect of slaughter weight and aging time on the quality of meat from Awassi ram lambs

Thirty Awassi ram lambs were used to investigate the effects of live weight at slaughter (SW) and aging time (AT) on meat quality attributes of Mm. Semitendinosus, Semimembranosus, Biceps femoris and Longissimus. Lambs were slaughtered at 20, 30 or 40 kg live weight, and muscles of each lamb carcass were aged for either 24 h or 7 days. Warner–Bratzler shear force values increased (P < 0.01) with increasing live weight and decreased (P < 0.01) by increasing AT in both M. Semimembranosus and Biceps femoris. Lightness (L*) of the four muscles decreased (P < 0.001) with increasing weight but was not affected by AT. Aging time increased (P < 0.05) redness (a*) in Mm.Semitendinosus and Longissimus. Cooking loss was reduced (P < 0.001) by increased AT in M. Longissimus and by increasing (P < 0.001) live weight in M.Semitendinosus. Aging time had no effect on expressed juice of all muscles but it was improved (P < 0.001) with increasing live weight in M. Semimembranosus. pH values were significantly influenced for Mm. Semimembranosus and Biceps femoris and values were higher for lighter weight and decreased with increasing weight. Aging time did not influenced pH. In conclusion, meat quality for lambs slaughtered up to 30 kg was better than for lambs slaughtered at 40 kg with quality being improved by increasing aging time.     

Muscle fibre characteristics and metabolic response at slaughter in pigs of different halothane genotypes and their relation to meat quality

Muscle samples for histochemical and biochemical analyses were taken immediately at slaughter from M. longissimus dorsi of pigs with different halothane genotypes (NN and nn). Fibre type composition was similar between groups but the nn-genotype had larger mean fibre areas and lower capillary density than the NN-genotype. At exsanguination the nn-genotype had lower muscle pH (pH(e)), higher lactate and ammonia and lower glycogen and phosphagen (ATP and CP) concentrations and twice as many glycogen-depleted type IIA and IIB fibres as compared with the NN-genotype. Muscle pH(e) was correlated positively to capillary density, glycogen and phosphagen concentrations and negatively to mean fibre area, ammonia and lactate concentrations. Ammonia concentrations were correlated negatively to ATP concentrations and positively to the percentage of glycogen-depleted IIB fibres. The highest reflectance and drip loss values were seen in the nn-genotype. The reflectance values were correlated positively to the percentage of glycogen-depleted type IIB fibres in muscle and the values for drip loss were correlated negatively to pH(e). These data show that fibre size and capillary density in muscle seem to be important factors that influence the metabolic response at slaughter and thus meat quality.     

Minerals, haem and non-haem iron contents of rhea meat

Mineral contents, haem and non-haem iron of rhea (Rhea americana) muscles Obturatorius medialis (OM), Iliotibialis lateralis (IL) and Iliofibularis (I) were determined. No differences between the three muscles were observed for calcium, phosphorus, magnesium and sodium. There is more potassium, zinc and copper in IL muscle than in OM and I muscles. For Manganese, OM and IL muscles show a higher content in comparison with I muscle. For selenium, IL and I muscles show the highest content compared to OM muscle. For total, haem and non-haem iron, the IL muscle shows the highest content respect to the other muscles. When compared to other meats, the minerals content of rhea meat show an elevated level in phosphorus, selenium and total and haem iron. The human health concern due to the deficient diet in selenium and iron, and their high contents in rhea meat will be of great importance in the promotion of this meat.     

Tenderness profiles of ten muscles from F1 Bos indicus x Bos taurus and Bos taurus cattle cooked as steaks and roasts

Twenty Bos taurus (Hereford x Angus crosses) and 20 F1 Bos indicus x Bos taurus heifers of the same age, management and feeding regimen, were harvested and evaluated at 2 days postmortem for carcass and meat traits. Ten muscles were obtained from the right sides and aged until 10 days postmortem. Bos indicus carcasses were lighter, had less fat cover, smaller ribeyes, and less intramuscular lipid (all p ≤ 0.05). Bos taurus longissimus lumborum, gluteus medius, triceps brachii, and semimembranosus muscles cooked as steaks and roasts had a lower Warner-Bratzler shear force (WBSF) (p ≤ 0.05) than those from Bos indicus. Bos taurus deep pectoral and semitendinosus muscles cooked as roasts had a lower WBSF (p < 0.05) than Bos indicus. Infraspinatus, longissimus lumborum, and semitendinosus muscles were more tender (p < 0.05) as roasts than steaks, whereas the opposite was true for the deep pectoral and semimembranosus muscles. Seven of the 10 muscles had lower WBSF (p ≤ 0.05) for Bos taurus when cooked as steaks, roasts or both.     

The influence of fiber size distribution of type IIB on carcass traits and meat quality in pigs

The effects of detailed characteristics such as the size and proportion of type IIB fibers in longissimus thoracis muscle on carcass traits and pork quality were investigated. A total of 96 pigs were classified into four groups by the proportion of different IIB fiber sizes. Group NS (high proportion of both small- and normal-sized IIB fibers) had a higher total number (136.4) and density (231.31) of type IIB fibers, backfat thickness (37.20 mm) and intramuscular fat content (4.77%) than the other groups (P < 0.05), whereas Group NS had the lowest values of cross-sectional area (3413.85 μm²) and diameter (60.15 μm) of type IIB fiber among the groups (P < 0.05). Pig muscles with higher percentage of large IIB fibers exhibit tougher, lighter and more exudative meat than pig muscles with a higher proportion of small- or normal-sized IIB fibers. Therefore, an increase in the proportion of large IIB fibers causes poor quality of pork.     

Utility for production of massaged products of selected wild boar muscles originating from wetlands and an arable area

Percentages of muscle fibre types, area of intramuscular fatty tissue (IMF) and changes in hardness, rheological properties as well as mean fibre cross-sectional area (CSA), and endomysium thickness of muscles from wild boars hunted in two different ecosystems (arable area vs. wetlands) were evaluated. Three muscles: Biceps femoris (BF), Semimembranosus (SM), and Longissimus (L) subjected to massaging (or not) for 4 h were studied.     

Effects of malate,lactate, and pyruvate on myoglobin redox stability in homogenates of three bovine muscles

We investigated the effects of glycolytic and tricarboxylic acid cycle metabolic intermediates on myoglobin redox forms and meat colour stability. Eighteen combinations of malate (M), lactate (L), and pyruvate (P) were added to beef Longissimus lumborum, Psoas major, and Semitendinosus muscle homogenates to study their effect on metmyoglobin formation during incubation at 25 °C. Changes in surface colour at 0, 2, 4, 8, and 12 h were evaluated by using reflecto-spectrophotometry [both L*, a*, and b* and wavelengths specific for metmyoglobin (MMb)]. Addition of M, L, and P alone or in combinations stabilized (P < 0.05) L*, a*, and b* values and myoglobin redox forms in muscle homogenates; however, there was a trend for P to be least effective. At the 2% concentrations for the individual metabolites, L was most effective at retarding MMb formation in the Semitendinosus (M was intermediate and P was least effective), and M was most effective in the Psoas major and L. lumborum muscles (L was intermediate and P was least effective). Metmyoglobin was reduced most effectively with a combination of metabolites (M + L > M + P > L + P). Enhancing meat with these metabolites can effectively extend colour life of post-rigor meat, apparently by providing more reducing conditions for myoglobin, thus increasing myoglobin redox form stability.