Higher Warner-Bratzler Shear Force Research Articles

Collagen characteristics affect the texture of pork Longissimus and Biceps femoris.

Connective tissue is considered to influence the toughness of pork, but most studies on connective tissue focus on the loin muscle. Cooking loss, Warner–Bratzler shear force (WBSF), texture profile analysis (hardness, springiness, chewiness, resilience, and cohesiveness), total and insoluble collagen content, the percentage of type III collagen relative to the total of type I and III collagen, proteoglycan content and intramuscular fat (IMF) content were measured for pork Biceps femoris (BF) and Longissimus thoracis et lumborum (LTL) and Pearson’s correlation was performed. The results showed that BF had higher WBSF, resilience, total, and insoluble collagen content than LTL (P < 0.05). When considering both muscles, total and insoluble collagen content were positively correlated (P < 0.05) with WBSF (r = 0.47 and 0.49, respectively), hardness (r = 0.49 and 0.50, respectively), cohesiveness (r = 0.50 and 0.50, respectively), chewiness (r = 0.58 and 0.59, respectively) and resilience (r = 0.63 and 0.63, respectively). The percentage of type III collagen content was negatively correlated (P < 0.05) with WBSF (r = −0.68) and hardness (r = −0.58). Collagen content was correlated (P < 0.05) with WBSF (r = 0.75) and hardness (r = 0.61) in LTL and with cohesiveness (r = 0.74) and resilience (r = 0.63) in BF. Collagen characteristics differ between muscles and contribute to pork texture in both LTL and BF.

Effects of Dietary Energy Density in a Fermented Total Mixed Ration Formulated with Different Ratios of Rice Straw and Cassava Pulp on 2- or 14-Day-Aged Meat Quality, Collagen, Fatty Acids, and Ribonucleotides of Native Thai Cattle Longissimus Muscle.

This study investigated the effects of dietary energy density in rice straw and cassava pulp fermented total mixed ration on pH, cooking loss, Warner–Bratzler shear force (WBSF), and collagen content of 2- or 14-d-aged native Thai cattle (NTC) Longissimus thoracic (LT) muscles and fatty acids and ribonucleotides of 2-d-aged LT. Eighteen yearling NTC (Bos indicus) were randomly divided into three dietary treatments (T1 = 8.9, T2 = 9.7, and T3 = 10.5 MJ ME/kg), with six bulls per treatment. The results showed that T1 had the highest WBSF (p < 0.05). However, T2 had similar WBSF to T3 (p > 0.05). With aging, cooking loss increased (p < 0.01), while WBSF decreased (p < 0.01). Insoluble and total collagen decreased with aging (p < 0.05). Dietary energy density had no effect (p > 0.05) on collagen content, ribonucleotides and most fatty acids. However, T1 had more (p < 0.05) decanoic (C10:0), vaccenic (C18:1n9t), trans-linolelaidic (C18:2n6t), eicosatrienoic (C20:3n6), and docosadienoic (C22:2) acids than T2 and T3. In terms of lowest feed cost with comparable tenderness to T2 and highest energy density, T3 may be well suited for feeding NTC. Aging for 14 days improves LT tenderness, but its cooking loss may affect yield and juiciness.

Effect of genetic background, pen size and outdoor access on meat quality in two slow growing broiler hybrids

ABSTRACT The aim was to evaluate the effect of two different rearing systems, indoor small pens (S) and big pens with outdoor access (B), on meat quality and fatty acid (FA) composition of two slow growing broiler hybrids (Rowan Ranger [RR] and Hubbard CYJA57 [H]). In addition, changes in the phospholipid FA composition, due to the possibility of more movement, were investigated. The results regarding meat quality were exclusively influenced by genotype, where RR chickens had higher breast weight, higher Warner-Bratzler shear force and higher pH than H chickens. Differences in lipid composition were found both due to hybrid and to the rearing system. The H birds were slightly leaner and had, therefore, higher proportions of phospholipids. Rearing in a big pen resulted in lower concentrations of 16:0 and higher concentrations of both total n-3 and n-6 fatty acids and of individual long chain polyunsaturated FA.

Determination of Package and Muscle-Type Influence on Proteolysis, Beef-Flavor-Contributing Free Amino Acids, Final Beef Flavor, and Tenderness

The objectives of this study were to determine the influence of package and muscle type on postmortem proteolysis and subsequent release of flavor-contributing free amino acids during storage. Beef strip loins and top sirloin butts (n = 20/subprimal) from USDA Low Choice carcasses were fabricated into 2.54-cm steaks (M. longissimus lumborum and M. gluteus medius) at 7 d postmortem. Steaks were randomly assigned to packaging treatments (carbon monoxide mother-bag [CO], high-oxygen modified atmosphere packaging [HIOX], polyvinyl overwrap [OW], or rollstock [ROLL]) and aged for an additional 14 d in dark storage. Steaks intended for OW were initially vacuum packaged during dark storage,then overwrapped just prior to display. Steaks were placed in coffin-style retail cases for 48 h under fluorescent lighting to simulate retail display. HIOX steaks exhibited the highest Warner-Bratzler shear force values (P < 0.05); the lowest desmin degradation rate (P < 0.05); the highest ratings for fishy, bitter, sour, and oxidized flavors; and the lowest overall tenderness scores (P < 0.05) and, in general, produced the lowest amount of free amino acids (P < 0.05) compared with all other treatments. Contrastingly, ROLL packaging produced the highest ratings for beef flavor identity, brown/roasted, bloody/serumy, and umami flavors (P < 0.05). Additionally, ROLL packaging exhibited (P < 0.05) greater desmin degradation in comparison with HIOX steaks. These data indicate that the optimum package for storage and aging is an anaerobic environment to maintain optimum flavor, tenderness, and postmortem proteolysis.

Collagen, intramuscular fat and proteolysis affect Warner-Bratzler shear-force of muscles from Bos taurus breed types differently at weaning, after backgrounding on pasture, and after feedlotting

Context The texture of beef is highly important for the eating experience, and there is a continued interest in understanding the biochemical basis for the variation in texture between cattle and their meat cuts in order to improve and minimise variation in tenderness due to production and processing factors. Aims The present study aimed to investigate the impact of characteristics of meat on Warner-Bratzler shear-force (WBSF) as an indicator of texture of beef as affected by breed type, age/feeding phase, and muscle. Methods Seventy-five steers of three breed types (Angus, Hereford and Wagyu × Angus) were slaughtered after weaning 6 months old (n = 15), after backgrounding 17 months old (n = 30) and after feedlotting 25 months old (n = 30). At slaughter three muscles (M. supraspinatus, M. semitendinosus and M. longissimus lumborum) were sampled from each steer, and pH, intramuscular fat and collagen content, sarcomere length, and proteolysis (desmin degradation) were measured and used to explain the variation in WBSF after 7 and 14 days of aging. Key results Meat from Hereford and Angus steers had higher WBSF after 7 days of aging compared with Wagyu × Angus steers, but after 14 days of aging there was only a difference between Hereford and Wagyu × Angus in the M. supraspinatus and M. semitendinosus. The WBSF of the young weaned steers and steers slaughtered after backgrounding were dependent on the degree of proteolysis in the muscles, whereas for steers slaughtered after feedlotting the content of collagen was more important for the WBSF. The amount of intramuscular fat had a significant impact on the differences in WBSF within the specific muscle studied. In contrast to the general dogma that WBSF increase with age, WBSF decreased in M. semitendinosus and M. longissimus lumborum from the weaned 6-month-old steers to the 25-month-old steers finished in feed-lot, whereas in M. supraspinatus the older feed-lot finished steers had a higher WBSF. Conclusion The factors contributing to the Warner-Bratzler shear force of beef depends on the age/feeding phase of the animal and the muscle and less on the breed type. Implications Optimisation of texture in beef through breeding and production should address different traits dependent on the age/feeding phase of the slaughter animal.

Effect of Different Photoperiods on Quality Attributes and Oxidative Stability of Breast Meat (M. Pectoralis Major) from Broilers

ObjectivesIn the broiler industry, high photoperiod (the duration of light exposure per day) regimes have traditionally been utilized to increase yield of breast meat, as well as maximize feed intake and growth rate in the growing period. However, recent literature reports this practice may have adverse effects on broiler welfare, resulting in impaired mobility and increased incidence of leg abnormalities. However, little information available in the current literature regarding effects of photoperiod on meat quality attributes and oxidative stability of broiler meat. Thus, the objective of this study was to evaluate the quality characteristics and lipid/protein oxidative stability of breast meat from broilers that were exposed to different photoperiod combinations.Materials and MethodsA total of 432 Ross 308 broiler chicks were allocated among 4 rooms each subjected to one of the following photoperiod treatments (hours Light: Dark): 20L:4D, 18L:6D, 16L:8D and 12L:12D, with 6 pens per treatment. At d 42, 2 broilers per pen (12 broilers/treatment) were randomly selected, harvested and air chilled for 24 h at 2°C. At l day postmortem, paired breast muscles (M. pectoralis) were collected for the meat quality analyses such as, water-holding capacity (drip/purge/cook loss), Warner-Bratzler shear force (WBSF), and display color for 7 d under fluorescent light (1450 lx). Lipid oxidation was assessed via the TBARS assay and protein oxidation by thiol content measured at d 1 and d 7 of display. The experimental design was randomized complete block design. Data were analyzed using the PROC MIXED procedure of SAS, and means were separated using least significant differences (P &lt; 0.05).ResultsPhotoperiod had no effect on fillet yield and pH (P &gt; 0.05). No significant difference in WBSF was found between treatments, although 12L:12D had a trend of higher WBSF (P = 0.08). Higher moisture loss during carcass chilling was found in carcasses from 20L:4D compared to 16L:8D and 12L:12D treatments (P &lt; 0.05). No other measure of water-holding capacity was affected, though the 16L:8D treatment demonstrated a trend of higher freezing/thawing loss compared to other treatments (P = 0.06). Proximate moisture, protein and lipid contents were unaffected by photoperiod (P &gt; 0.05), but higher ash was observed in 16L:8D over 20L:4D and 18L:6D (P &lt; 0.05). Different photoperiod combinations affected color stability of breast meat during display (P &lt; 0.05). Of note, fillets from 20L:4D maintained highest L* and hue angle, and least a* values (P &lt; 0.05), indicating inferior color stability compared to other treatments. Oxidation increased with display, and fillets from 20L:4D and 18L:6D had higher TBARS over 12L:12D (P &lt; 0.05); no photoperiod effect was observed in thiol content (P &gt; 0.05).ConclusionResults suggest 20L:4D photoperiod regimes may be detrimental to meat quality, as carcasses from this treatment group had higher moisture loss during chilling, and color measurements characterized these fillets as being paler and more discolored than other treatments. Fillets from 12L:12D maintained lower TBARS than 20L:4D and 18L:6D, suggesting photoperiod regimes allowing more hours of dark may be beneficial in improving oxidative stability. Further studies determining the effects of photoperiod on quality and protein functionality of chicken meat for processing technological would be highly warranted.

Effect of Slaughter Age on Muscle Fiber Composition, Intramuscular Connective Tissue, and Tenderness of Goat Meat during Post-Mortem Time.

This study evaluated the effects of slaughter age and post-mortem time on meat quality traits, tenderness, histochemical analyses, and perimysium thickness in the longissimus thoracis (LT) muscle of the Korean native black goat (KNBG) maintained at 4 °C for up to 21 days post mortem. Samples of LT muscle were obtained from the carcasses of 24 KNBGs, including old and young goats (AG, n = 12, 18 months of age; YG, n = 12, 9 months of age), to measure all analyses during 21 days of post-mortem time. AGs had a higher percentage of type I fiber but a lower percentage of type IIA fiber than YGs (p < 0.05). AGs had higher a* value, lower released water (RW) %, and higher Warner–Bratzler shear force (WBSF) value than YGs (p < 0.05). The perimysium thickness (PMT) of AGs was also higher than that of YGs (p < 0.05). Although the PMT did not change during post-mortem period, the WBSF value of AGs was higher than that of YGs after 21 days post mortem (p < 0.05). The results imply that AGs are tougher than YGs due to their muscle fiber characteristics and thicker perimysium.

Characterization of surface orientation and tenderness of sous vide processed edible offal and psoas muscle from Dohne Merino sheep

The microstructural orientation and tenderness of edible offal and the psoas minor muscle from Dohne Merino sheep were compared in this study. Following evisceration and cleaning, fresh meat samples were collected from slaughtered lambs and ewes of different age groups and thermally processed to varying degrees of doneness using sous vide apparatus. A scanning electron microscope (SEM) was used for the characterization of the surface orientation and elemental composition. The results for tenderness showed that edible offal with anisotropic orientation had higher Warner-Bratzler shear force (WBSF) values, but those with some degrees of uniformity (isotropicity) in their surface orientation were comparatively tender. The rumen and trachea from the lambs, six-tooth and eight-tooth sheep at 10 - 12, 23 - 36 and 28 - 48 months old at slaughter had the highest WBSF values among all the meat samples. Our findings showed that edible offal from the lambs with isotropic orientation was more tender and richer in protein than those from ewes. Also, processing the psoas minor muscle and edible offal with sous vide at 100 oC in the shortest cooking time of 30 minutes had the greatest effect on tenderness of the meat samples. In descending order, the psoas minor muscle, liver and tongue from the lambs were found to be inherently more proteinaceous than other meat samples. The differences observed in the tenderness and protein contents of the edible offal and the psoas muscle could be attributed to variations in the microstructural organization of the muscle fibres in Dohne Merino and to their response to thermal processing. Keywords: anisotropy, doneness, isotropy, meat processing, Merino, scanning electron microscopy

Comparison of carcass traits, meat quality and expressions of MyHCs in muscles between Mashen and Large White pigs

The aim of this study was to evaluate the differences in carcase traits, meat quality and muscle characteristics (mean fibre diameter and MyHCs levels of expression) between Mashen and Large White pigs. A total of 60 pigs (30 Mashen pigs and 30 Large White pigs, half male and half female in each breed) were used in this experiment. Results showed that Mashen pigs exhibited lower slaughter weight, reduced back-fat thickness, reduced loin eye area and lower lean meat ratio than Large White pigs (p < .05). Meat from Large White pigs had higher pH1, greater drip losses, higher Warner-Bratzler shear force values, higher lightness, higher yellowness, and greater mean diameter of muscle fibres. Also, meat from Large white pigs had lower cooked yield, lower redness, and reduced intramuscular fat content than meat from Mashen pigs (p < .05). The contents of 17 amino acids, total amino acids, essential amino acids and umami amino acids in the longissimus dorsi of Mashen pigs were higher than those in Large White pigs (p < .05). Large White pigs had higher monounsaturated fatty acids and lower polyunsaturated fatty acids than Mashen pigs (p < .05). Meanwhile, the expression of MyHCI was significantly higher and the expression of MyHCIIb was lower in Mashen than in Large White pigs (p < .05). The higher MyHCI and lower MyHCIIb found in muscles from Mashen pigs might partially explain meat quality differences found between the two breeds in the present study. These results provide valuable information for meat quality differences between Mashen and Large White pigs.HighlightsCarcase traits and meat quality between Large White and Mashen pigs exhibited significant differences.The total amino acids, essential amino acids and umami amino acids in Mashen pigs were higher than those in Large White pigs.Large White pigs had higher monounsaturated fatty acids and lower polyunsaturated fatty acids than Mashen pigs.The expression of MyHCI was significantly higher and the expression of MyHCIIb was lower in Mashen than in Large White pigs.

Effect of ractopamine on physicochemical characteristics and collagen solubility in finishing pigs

The objective of this study was to investigate physicochemical characteristics and collagen solubility of pigs fed with dietary ractopamine (RAC) during finishing period. Thirty of three-way crossbred pigs (Large White × Landrace × Duroc) with an initial bodyweight (BW) of 18.0 ± 0.5 kg were randomly assigned to one to three dietary RAC inclusions (0, 20, or 40 mg/kg) fed during finishing period (60-100 kg BW). Each group consisted of five gilts and five barrows. After 109 day of raising period, all pigs were slaughtered at the average weight of 100 kg. Longissimus dorsi muscle (LD) was taken from each carcass after overnight chill and analyzed for physical characteristics, chemical composition, and collagen solubility. The LD from pigs fed 40 mg/kg of RAC had lower a* value (p &lt; 0.01) than others. Pigs fed with 40 mg/kg of RAC had higher Warner-Bratzler shear force (p &lt; 0.05) than pigs fed without RAC. Pigs fed with dietary RAC had lower glycogen content than control (p &lt; 0.01). While other chemical compositions and collagen solubility of LD were not affected by dietary RAC (p &gt; 0.05). Gilts had larger muscle fibers (p &lt; 0.01), lower glycogen content (p &lt; 0.05), higher content of insoluble collagen (p &lt; 0.05), total collagen (p = 0.054), and collagen solubility (p = 0.054) than barrows.

Relating Muscle Fiber Morphometrics and Protein Degradation to Meat Quality in a Multibreed Herd

ObjectivesBrahman and Brahman-influenced cattle provide integral adaptations that benefit the cattle herd in the sub-tropical United States. Their heat tolerance and parasite resistance make them ideal for warmer climates; however, they tend to exhibit less desirable carcass and palatability traits. When compared to Angus, Brahman are lower marbling, less tender, and have more connective tissue. The objective of this study is to determine influence of Brahman genetics on muscle metabolic phenotype and postmortem proteolysis.Materials and MethodsCattle used in this study were part of a long-term genetic study involving Angus, Brahman, and Angus-Brahman crossbreeding. Although these cattle represent a continuous spectrum of Angus-Brahman genetic variation, they were divided into 6 breed groups for analysis: Angus; 3/4 Angus, 1/4 Brahman; Brangus; 1/2 Angus, 1/2 Brahman; 1/4 Angus, 3/4 Brahman; and Brahman. Steers (n = 6 per breed group) were harvested and samples from longissimus lumborum muscles were collected at 0 h, 24 h, and 14 d post-mortem. Western blotting was used to assess proteolysis during the 14 d aging period, including degree of autolysis of the proteolytic enzyme, µ-calpain; content of the calpain inhibitor, calpastatin; and the extent of degradation of desmin. Tenderness was determined objectively by Warner-Bratzler shear force (WBSF). The data was analyzed using multivariate methods in JMP. Nonparametric correlations were used to calculate the relationships between 24 h µ-calpain autolysis, WBSF, citrate synthase activity, and breed group.ResultsAs the percentage of Brahman genetics increases, WBSF increase as expected (R = 0.45, P < 0.01). The degree of µ-calpain autolysis at 24 h decreases as WBSF values increase (R = -0.49, P < 0.01), and autolysis decreases as the percentage of Brahman increases (R = -0.43, P < 0.01). Brahman genetics tended to influence oxidative capacity (P = 0.06), as citrate synthase activity increased with greater percentage of Brahman genetics.ConclusionAs expected, Brahman influenced cattle produced tougher steaks, evidenced by higher WBSF and decreased protein degradation. Postmortem proteolysis and muscle fiber type will be utilized to establish predictors for the optimum breed group that provides desirable meat quality and palatability traits, while having enough Brahman influence to thrive in sub-tropical climates.

The association of CAPN1, CAST, SCD, and FASN polymorphisms with beef quality traits in commercial crossbred cattle in the Czech Republic

Genetic variability of four polymorphisms (CAPN1, CAST, SCD, and FASN) was evaluated and the relationships between them and the beef quality traits (tenderness and fatty acid composition) in Czech crossbred cattle population were assessed. Totally 331 animals were genotyped using multiplex PCR-RFLP. For the CAST NM174003.2:c.155C&amp;gt;T the CC genotype was associated with higher Warner-Bratzler shear force (CC&amp;nbsp;&amp;gt; CT, P &amp;lt; 0.001; CC &amp;gt; TT, P &amp;lt; 0.05) and our results (CC &amp;gt; TT &amp;gt; CT) suggest a possible effect of overdominance. The CAPN1 AF252504.2:c.947G&amp;gt;C did not significantly influence the beef tenderness (strongly influenced by misbalance between the genotype frequencies) suggesting the breed specific effect of this marker. Our association study of the SCD AB075020:c.878T&amp;gt;C polymorphism revealed a positive effect of allele C on myristoleic acid content (CC &amp;gt; CT &amp;gt; TT, P &amp;lt; 0.01). The significant influence of FASN AF285607:g.17924A&amp;gt;G on fatty acid profile was confirmed in the content of myristoleic acid (AG &amp;gt; GG, P &amp;lt; 0.05), palmitoleic acid (AA &amp;gt; AG &amp;gt; GG, P &amp;lt; 0.05, P &amp;lt; 0.001), stearic acid (AA &amp;gt; GG, P &amp;lt; 0.05), myristic acid (AG &amp;gt; GG, P &amp;lt; 0.05), and palmitic acid (AG &amp;gt; GG, P &amp;lt; 0.05). Thus in our population the SNPs of FASN and SCD appeared to be useful markers for selection of animals according to the fatty acid profile as well as SNP of CAST for beef tenderness. &amp;nbsp;

Effects of ractopamine hydrochloride and zilpaterol hydrochloride supplementation on longissimus muscle shear force and sensory attributes of beef steers 1

Effect of ractopamine hydrochloride (RH) and zilpaterol hydrochloride (ZH) on LM shear force and sensory attributes was determined using pens (n = 40) British × Continental crossbred steers randomly allocated to one of the following treatments: control; RH fed at 200 (RH 200) or 300 mg • steer(-1) • d(-1) (RH 300), or 400 mg • steer(-1) • d(-1) (RH 400) top-dressed for the final 30 d of feeding; or ZH fed at 7.5 mg/kg, beginning 23 d before slaughter with a 3-d withdrawal. Two replicates (pens) per treatment were represented in four blocks. Eighteen carcasses per pen were randomly selected and one 5-cm LM sample was removed from both carcass sides to be used for shear force and sensory evaluation. Samples were aged for 14 d, frozen at -28.8 °C, and cut into 2.5-cm steaks. All steaks were cooked to an internal temperature of 71.1 °C before being evaluated for Warner-Bratzler shear force (WBSF), slice shear force (SSF), or being fed to trained sensory panelists. Increasing dose and potency of β-agonist increased WBSF by 4 to 17% and SSF by 5 to 24% (P < 0.05). Steaks from steers fed ZH had higher WBSF and SSF values compared with all other treatments (P < 0.05), whereas steaks from controls and steers fed RH 200 were not different (P > 0.05). Probability of steaks failing to meet shear force standards to be certified tender (WBSF <4.4 kg, SSF < 20 kg) was increased from an initial probability of <0.06 in steaks from steers in the control treatment to 0.10 to 0.20 in steers fed RH 400 or ZH (P < 0.05). No difference was detected in panel ratings for overall tenderness of steaks from steers fed RH 200 compared with controls (P > 0.05). Steaks from steers fed RH 300 and RH 400 were comparable for all sensory attributes; however, both RH 300 and RH 400 were rated lower for overall tenderness than controls (P < 0.05). Panelists failed to detect differences in overall tenderness of steaks from steers fed RH 400 and ZH (P < 0.05). Panelists detected no difference in flavor profile or juiciness among treatments (P > 0.05). Results from this study indicated β-agonists negatively affected beef tenderness and these effects may be more noticeable in steers supplemented with ZH and higher doses of RH.

Effects of supplementing two levels of magnesium aspartate and transportation stress on pork quality and gene expression of 𝛍-calpain and calpastatin of finishing pigs

The objective of this study was to investigate the effects of supplementing swine finishing diets with two levels of magnesium aspartate (MgAsp) and short-term transportation stress on blood parameters, pork quality and the mRNA abundance of μ-calpain and calpastatin in muscles of finishing pigs. Thirty-six crossbred finishing pigs (mean BW 90 kg) were assigned randomly to 0, 1000, or 2000 mg supplemental Mg from MgAsp per kg of diet for five days before slaughter. Then six pigs from each dietary treatment were subjected either to no transportation stress (NTS) or 2 h of transportation stress (TS). Transportation stress resulted in higher concentrations (p < 0.01) of serum calcium, glucose and cortisol, lower pH (p < 0.01), higher Warner-Bratzler shear force (WBSF) (p < 0.05) and higher calpastatin mRNA abundance (p = 0.05) of longissimus muscle (LM) compared with NTS treatments. Supplementation of MgAsp in TS treatments increased serum Mg concentration (p < 0.05) at 2000 mg of Mg/kg, reduced drip loss (p < 0.05) and improved pork quality colour (p < 0.05) at 2000 mg of Mg/kg, and decreased 1-day and 3-day WBSF (p < 0.05) at 1000 mg of Mg/kg compared with TS treatments fed the control diet. It is concluded that supplementation of MgAsp improves water-holding capacity and pork colour, and alleviates the negative effects of transportation stress on meat tenderness.

Effect of Iberian × Duroc genotype on dry-cured loin quality

Dry-cured loins from three different pig genotypes were studied: GEN1: ♂ Iberian × ♀ Duroc1, GEN2: ♂ Duroc1 × ♀ Iberian; GEN3: ♂ Duroc2 × ♀ Iberian. GEN1 and GEN2 are reciprocal crosses, while the difference between GEN2 and GEN3 is the Duroc sire line. The genotype of pigs Duroc1 was selected for the manufacture of dry-cured meat products, while the genotype Duroc2 was selected for meat production. The chemical composition of the dry-cured loins was significantly different, especially the intramuscular fat (IMF) content which was highest in GEN2. Dry-cured loins from GEN3 showed lower CIE a ∗ and chroma values. IMF from GEN2 was more saturated whereas GEN3 had higher percentages of PUFA and MUFA. Loins from GEN3 had higher TBA-RS values ( p > 0.05) and hexanal contents. Loins from GEN3 had higher Warner–Bratzler shear force ( p > 0.05) and instrumental hardness than those from GEN2, being intermediate in GEN1. Panellists considered that loins from GEN2 were more marbled, more odorous, juicier, sweeter and less salty than loins from GEN3. Therefore, loins from GEN2 had the best quality, followed by GEN1, while GEN3 had the worst quality.

Effects of electrical stimulation, chilling temperature and hot-boning on the tenderness of bovine muscles

The objective of this study was to determine the effects of hot-boning, low voltage electrical stimulation (ES) and chilling temperature on the tenderness of bovine M. longissimus dorsi (LD) and M. semimembranosus (SM) muscles. LD ( n = 32) and SM ( n = 32) muscles were subjected to different post-mortem treatments; hot-boning (before 90 min post-mortem), cold-boning (at 48 h post-mortem), low voltage ES and rapid or slow chilling. Hot-boned muscles which were not electrically stimulated (NES) had higher Warner Bratzler shear force (WBSF) values ( P < 0.001) and shorter sarcomeres ( P < 0.001) than cold-boned muscles. Hot-boned muscles subjected to ES had lower pH values ( P < 0.001) post-stimulation and up to 8 h post-mortem than NES muscles. At both chilling temperatures WBSF values were lower in ES hot-boned LD and SM muscles at days 2, 7 and 14 post-mortem than NES muscles. Hot-boned muscles subjected to slow chilling had longer sarcomeres ( P < 0.001) than those subjected to fast chilling. In hot-boned SM muscles, ES resulted in longer sarcomere lengths ( P < 0.001). However, ES did not have a significant effect on the sarcomere length of LD muscles. As indicated by WBSF values all muscles tenderised during ageing, including muscles which were ‘cold shortened’. Proteolysis was not the main reason for differences in WBSF values between ES and NES muscles as judged by qualitative sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). A combination of slow chilling and ES had a positive effect on hot-boned muscles with respect to WBSF values.

Characterization and consumer acceptance of three muscles from Hampshire × Rambouillet cross sheep expressing the callipyge phenotype1

Eight Hampshire x Rambouillet crossbred wethers expressing the callipyge phenotype and eight Hampshire x Rambouillet half-sibling wethers with a normal phenotype were slaughtered when they reached 59 kg. The supraspinatus (SPM), longissimus (LM), and semitendinosus (STM) muscles were analyzed to determine callipyge effects on calpain and calpastatin activities, sarcomere length, percentage of muscle fiber types, and muscle fiber areas. After 14 d of aging, chops were frozen until analyses for trained sensory panel evaluations, Warner-Bratzler shear force values, and consumer perceptions of tenderness, flavor, juiciness, and overall satisfaction of chops were conducted. Calpastatin activity was 57% greater (P < 0.05) and m-calpain activity was 33% greater (P < 0.05) in muscles from carcasses of callipyge than normal sheep. Sarcomeres were shorter (P < 0.001) in the LM than the SPM or STM, regardless of phenotype. Muscle fiber area was 76% larger (P < 0.05) in the LM of callipyge than normal sheep, but muscle fiber area was not affected (P > 0.05) by phenotype in the SPM or STM. Phenotype had no effect (P = 0.12) on the percentage of slow-twitch, oxidative fiber types in any of the three muscles. In STM and LM from callipyge lambs, the percentage of fast-twitch, oxidative/glycolytic fibers was lower (P < 0.05) and that of fast-twitch-glycolytic fibers was higher (P < 0.05) than in their normal counterparts. Phenotype did not affect (P = 0.90) the fiber type percentage in the SPM. Callipyge LM were less tender and normal LM were more tender than other chops (P < 0.05). Callipyge loin chops had higher Warner-Bratzler shear force values than other chops (P < 0.001). Consumers rated fewer (P < 0.05) callipyge loin and shoulder chops acceptable in juiciness, tenderness, and overall acceptability than normal chops, but phenotype did not affect (P > 0.05) consumer acceptability of leg chops. These results indicate that LM from Hampshire x Rambouillet sheep displaying the callipyge phenotype had higher calpastatin activity and were less tender than the LM from normal sheep. In addition, consumer perceptions indicated that only one in 10 leg chops, one in five shoulder chops, and one in four loin chops from callipyge sheep were unacceptable.

A national audit of retail lamb loin quality in Australia

A retail audit of lamb loin tenderness was conducted over a 12-month period to determine the variation in tenderness of Australian lamb. Tenderness was objectively measured using Warner–Bratzler (WB) shear force. Muscle pH and cooking loss were determined on all samples and colour was measured on a sub-sample of loins. A total of 909 midloins from retail butcher shops and supermarkets located in four Australian capital cities (Sydney, Canberra, Melbourne, and Perth) were evaluated at four sampling times (December 1997 and March, June, and October 1998). Overall, 20.3% of all midloins purchased had a WB shear force value above the threshold level of 5 kg. Generic samples from Melbourne butcher shops were similar for WB shear force on average to the generic samples from Canberra and Sydney, whereas those from Melbourne supermarkets had significantly ( P<0.001) higher WB shear force and were in line with generic samples from Perth. In both Canberra and Perth, alliance (branded) lamb had a greater WB shear force ( P<0.05) than generic lamb. No relationship was found between price per kg and shear force ( r=0.02) for loins purchased in Sydney ( n=220). Price per kg differed between months ( P<0.001) and suburbs ( P<0.001), but not between retail butcher shops and supermarkets. Of the midloins tested, 10.3% had a pH above the critical point of 5.8. Midloins from the December 1997 sampling had a lower pH ( P<0.01) than those sampled at other months. Those sampled in Melbourne and Perth had a similar mean pH, which were lower ( P<0.001) than Canberra and Sydney samples. The findings from this quality audit suggest that there is room to improve the tenderness of Australian lamb sold in the domestic market. A lamb eating quality assurance system, based on set protocols, is one approach that is currently being investigated in Australia to ensure the supply of consistently high eating quality lamb to consumers.

Effects of end-point temperature, reheating, holding time, and holding temperature on beef tenderness (2002)

We cooked steaks from two muscles; outside round (biceps femoris), and strip loin (longissimus lumborum) with an electric belt grill. Biceps femoris steaks had higher Warner-Bratzler shear force (WBSF), connective tissue force (WB Cforce), and myofibrillar force (WB Mforce) values than longissimus lumborum steaks. Holding biceps femoris steaks at 144°F after cooking increased WB C-force (P<0.05) and WB M-force (P<0.01) as compared to holding them at 135°F. Holding biceps femoris steaks for 15 min decreased shear force by 12%, whereas the decrease was only 3% from holding for 30 min, likely because more moisture was lost with the longer holding time. Reheating had the only significant effect on longissimus lumborum steaks' WB measures because low collagen content of this muscle is not affected by holding time or temperature.

ULTRA‐RAPID CHILLING: CHILLING RATE EFFECTS ON THE APPEARANCE OF LAMB CARCASSES AND TENDERNESS OF LAMB CHOPS

ABSTRACT The effects of different chilling rates on the visual attributes of lamb carcasses and the tenderness of lamb chops were investigated. Carcasses (n=72) were chilled at ‐20C, ‐10C, ‐4C or + 4C. After chilling all carcasses were stored at +4C for up to 8 days. Samples were taken at 2, 6 and 9 days postmortem for sarcomere length, Warner‐Bratzler shear force and sensory analysis. Carcasses were visually appraised at 2, 6 and 9 days postmortem for fat color, flank color, visible vein color, wetness and overall acceptability. Carcasses chilled at ‐20C had significantly higher Warner‐Bratzler shear force values than the other chilling treatments at 2 and 6 days but not at 9 days postmortem. No difference (P&gt; 0.05) was found in Warner‐Bratzler shear force or sensory tenderness between any of the treatments by 9 days postmortem. Carcasses did not differ (P&gt;0.05) in fat color, flank color or overall acceptability at any stage postmortem. Carcasses chilled at ‐20C had slightly darker (P&lt; 0.05) vein color at 2 days postmortem but this was not evident by 6 days postmortem. Carcasses that were chilled at ‐20C had significantly lower evaporative weight losses than carcasses in any of the other treatments. Rapid chilling did not adversely affect the tenderness of lamb chops or appearance of lamb carcasses at 9 days postmortem compared with conventional chilling.