The Solubility of Intramuscular Collagen in Meat Animals of Various Ages

Carcass and Meat Characteristics of Cull Heifers from Different Genetic Groups Fed Diets with Different Sources of Nonprotein Nitrogen in Confinement

The aim of this study was to evaluate the effect of genetic groups and diets with different sources of nonprotein nitrogen (NPN) on the carcass and meat characteristics of beef heifers. The meat from 40 heifers (20 ½ Angus ½ Nellore (A × N) and 20 ½ Charolais ½ Nellore (L × N)), finished in feedlots, was used. The heifers were fed diets containing different sources of NPN-(1) a diet with livestock urea and protected urea (LPU) and (2) a diet with extruded urea (EU)-in a completely randomized design with a 2 × 2 factorial arrangement. Carcass, composition and meat quality evaluations were carried out. There were no significant interactions between diet and genetic group for most of the variables evaluated (p > 0.05). The A × N heifers had higher hot carcass weights (305.73 vs. 279.80 kg), loin eye areas (80.87 vs. 75.45 cm2), subcutaneous fat thicknesses (8.69 vs. 6.35 mm) and lower shear forces (6.98 vs. 7.7 kg) compared to the C × N heifers (p < 0.05). The meat from the A × N heifers had higher proportions of saturated fatty acids (49.41 vs. 47.95%), with no effects on the proportions of monounsaturated (47.57%) and polyunsaturated (4.01%) fatty acids. The A × N heifers had better carcass and meat characteristics, while the C × N heifers had meat and fat with better fatty acid profiles.

Effects of Zilpaterol Hydrochloride Supplementation on Growth Performance, Carcass Characteristics and Meat Quality for Steers Differing in Breed Type

To determine the effects of zilpaterol hydrochloride (ZH) on growth performance, carcass characteristics and meat quality for steers differing in breed type, steers with British (B; n = 76) or British × Continental (BC; n = 57) backgrounds were allocated to a randomized incomplete block design with a 2 × 2 treatment structure. Pens within each block × breed type were randomly assigned to either ZH (8.3 mg/kg of DM; fed for 20 d before slaughter, followed by a 3-day withdrawal) or control (CON; 0 mg/kg ZH). Steers were subjected to ultrasound immediately before ZH inclusion and following withdrawal to determine the influence of ZH on changes in longissimus muscle area (LMA), fat thickness and percent intramuscular fat (IMF). Carcass data were collected, and the longissimus lumborum was collected for analysis of tenderness, moisture percentage, crude fat content, collagen content, postmortem proteolysis and sensory attributes. The ZH × breed type interaction did not influence (p > 0.05) the feedlot performance, carcass or meat quality attribute traits evaluated, with the exception of moisture percentage. Responses among breed types were as expected for B vs. BC cattle types. Supplementation with ZH improved (p < 0.05) LMA and yield grade but increased Warner-Bratzler shear force.

Comparison of Chemical Composition, Quality, and Muscle Fiber Characteristics between Cull Sows and Commercial Pigs: The Relationship between Pork Quality Based on Muscle Fiber Characteristics

This study aims to compare the chemical composition, quality, and muscle fiber characteristics of cull sows and commercial pigs, investigating the effect of changes in muscle fiber characteristics on pork quality. The proximate composition, color, pH, water-holding capacity (drip loss and cooking loss), protein solubility, total collagen content, and muscle fiber characteristics of cull sows (n=20) and commercial pigs (n=20) pork were compared. No significant differences were found between cull sows and commercial pigs in terms of proximate composition, drip loss, protein solubility, or total collagen content of their meat (p<0.05). However, cull sow pork exhibited a red color and a higher pH (p<0.05). This appears to be the result of changes in muscle fiber number and area composition (p<0.05). Cull sow meat also displayed better water-holding capacity as evident in a smaller cooking loss (p<0.05), which may be related to an increase in muscle fiber cross-sectional area (p<0.05). In conclusion, muscle fiber composition influences the pork quality; cull sow pork retains more moisture when cooked, resulting in minimal physical loss during processing and can offer more processing suitability.

Muscle Fiber, Connective Tissue and Meat Quality Characteristics of Pork from Low Birth Weight Pigs as Affected by Diet-Induced Increased Fat Absorption and Preferential Muscle Marbling

This study investigated how birth weight differences in piglets affected carcass and muscle fiber properties as well as meat quality at slaughter. Within litters, piglets were grouped according to their birth weight as either normal (NBW; 1.62-1.73 kg) or low (LBW; 1.18-1.29 kg). At 5 weeks of age, NBW piglets were randomly transitioned to control (C) or isocaloric high fat diets derived from non-dairy (HF), while LBW piglets were randomly transitioned to high fat diets derived from non-dairy (HF) or dairy sources (HFHD). Piglets were reared in individual pens under standardized housing and feeding conditions. Live weight was recorded weekly, and pigs were slaughtered at 12 weeks of age. Hot carcass weights, dressing percentages, lean meat yield, and primal cut proportions were determined. The m. longissimus thoracis was collected from the right side of the carcass for measurement of physical and chemical properties of meat and muscle fiber characteristics. Results indicated that LBW pigs compensated for their live weight compared to NBW pigs at 6 weeks of age. The mean muscle fiber diameter of LBW-HFHD group is significantly higher than NBW-C and NBW-HF group, and the type I muscle fiber diameter is significantly higher than NBW-C group. Dairy fat inclusion in LBW pig diet reduced carcass back fat thickness. This increased the calculated lean meat yield to be comparable to that of NBW pigs fed a commercial diet. Incorporating dairy-sourced high-fat into LBW pigs' diets appears to be an effective strategy for producing carcasses equivalent to NBW pigs.

Influence of Sex on Meat and Fat Quality from Heavy Alentejano Pigs Finished Outdoors on Commercial and High Fiber Diets

This work aimed to examine the effects of sex on meat and fat quality traits from thirty Portuguese Alentejano (AL) pigs reared in outdoor conditions. These pigs were divided into three groups and fed ad libitum. From ~40 to 130 kg LW, castrated (C group) and intact animals (I and IExp) consumed commercial diets. Until slaughter (~160 kg), C and I pigs remained on commercial diets, and IExp changed to a more sustainable experimental diet with locally produced pulses and byproducts. Samples were collected from the Longissimus lumborum (LL), Psoas major (PM), and dorsal subcutaneous fat (DSF). At ~160 kg, the PM muscle of intact pigs presented lower intramuscular fat content than that of C pigs, while total collagen was higher. Additionally, PM myoglobin was lower and lightness (L*) was higher in intact pigs. Regarding DSF, moisture and total protein contents were higher and total lipids were lower in intact than in castrated pigs, while color parameters were not significantly different. Finally, antioxidant capacity measured in the LL muscle showed an overall lower value in intact pigs. However, lipid oxidation values were not significantly different between the experimental groups and only increased with storage time. Outdoor-reared intact AL pigs produced leaner and less saturated pork and fat compared to castrated ones. Despite the lower antioxidant activity observed in the LL muscles of intact pigs, the lipid oxidative stability of cooked meat was not different among the experimental groups.

Outdoor Finishing of Intact Male Portuguese Alentejano Pigs on a Sustainable High-Fiber Diet: Impacts on Blood, Growth, Carcass, Meat Quality and Boar Taint Compounds

This trial evaluated the effect of sex on the blood, growth, carcass, meat quality, and boar taint compounds in male Alentejano (AL) pigs (n = 30). From ~40 to 130 kg LW, castrated (C) and intact pigs (I and IExp groups) were fed commercial diets ad libitum. Between ~130 and 160 kg (slaughter), C and I pigs continued on commercial diets, while IExp were fed an experimental diet containing locally produced pulses and by-products aimed at reducing boar taint. At ~160 kg, blood urea levels were higher in IExp than C pigs, triacylglycerols were lower in both intact groups, and cortisol was lower in IExp. IExp pigs exhibited faster growth, improved feed conversion ratio, carcass higher commercial yield and leaner meat than C pigs. The loin intramuscular fat in intact pigs was lower, less saturated and more polyunsaturated, while total collagen was higher. Fat androstenone content was higher in intact pigs and skatole content was similar across treatments, although they were below threshold values for consumer detection. Finally, although boar taint compounds were low in intact AL pigs raised outdoors, adding pulses and by-products to the experimental diet did not result in a reduction in fat skatole content compared to pigs fed the commercial diet.

A South African beef quality survey

In this study a survey of various meat quality characteristics of beef loin cuts was conducted in the City of Tshwane Metropolitan Municipality (Gauteng Province of South Africa) to determine the variation and consistency of beef quality of products purchased over time. Four hundred and twenty beef loin samples were collected on 20 occasions over 308 days from 13 outlets of 2 supplier types (butcher and supermarket). Packaging type, label information and price were considered for the evaluation of meat tenderness, colour, cooking loss, tissue composition and steak thickness. The results demonstrate that large variation in characteristics relevant to consumers' choice and satisfaction among and within different products sold as porterhouse steak in South Africa. In particular, muscle tenderness varied (P < 0.0001) across the 20 products and also showed significant inconsistency over the 20 purchasing events for certain products.

Drivers of Palatability for Cats and Dogs-What It Means for Pet Food Development

The pet food industry is an important sector of the pet care market that is growing rapidly. Whilst the number of new and innovative products continues to rise, research and development to assess product performance follows traditional palatability methodology. Pet food palatability research focuses on the amount of food consumed through use of one-bowl and two-bowl testing, but little understanding is given to why differences are observed, particularly at a fundamental ingredient level. This review will highlight the key differences in feeding behaviour and nutritional requirements between dogs and cats. The dominant pet food formats currently available and the ingredients commonly included in pet foods are also described. The current methods used for assessing pet food palatability and their limitations are outlined. The opportunities to utilise modern analytical methods to identify complete foods that are more palatable and understand the nutritional factors responsible for driving intake are discussed.

Characterization of Type I and Type III Collagen in the Intramuscular Connective Tissue of Wuzhumuqin Sheep

Intramuscular connective tissue (IMCT) collagen is an important factor in meat quality. This study analyzed the characteristics of type I and III collagen in the IMCT of the semitendinosus (SD) and longissimus dorsi (LD) of Wuzhumuqin sheep at different growth stages (6, 9, 12, and 18 months). Utilizing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy (FTIR), collagen types I and III were successfully isolated and shown to contain an intact triple helix structure. Immunofluorescence revealed that these collagens were located in the endomysium and perimysium. Collagen-related genes were significantly expressed in sheep aged 9 and 12 months. The amino acid content increased with age in type I collagen whereas it decreased in type III collagen. Furthermore, type III collagen contained more hydroxyproline (Hyd) than type I collagen. Differential scanning calorimetry (DSC) revealed that the thermal stability of collagen increased with age, accompanied by a decrease in solubility. Semitendinosus muscle had more collagen cross-linkages than LD muscle due to the high pyridinoline (Pyr) content in the endomysium. Finally, a correlation analysis highlighted the multiple correlations between characteristics in different types of collagen during sheep growth. In summary, the collagen characteristics in the IMCT of sheep were impacted by collagen type, muscle type, and age. Furthermore, the various correlations between these characteristics may play an important role in the development of IMCT.

Toughness Variations among Natural Casings: An Exploration on Their Biochemical and Histological Characteristics

We investigated the mechanical, biochemical, and histological properties of hog and sheep casings produced in different countries to elucidate the responsible factors for the toughness quality of natural casings. The toughness and collagen characteristics of sheep and lamb casings were also investigated to elucidate the effect of animal slaughter age on the relationships between connective tissue and the mechanical properties of natural casings. The results showed that the main component of hog and sheep casings was collagen with many layers of sheets. The contents of collagen, elastin, and proteoglycan in hog and sheep casings were similar. The toughest Chinese casings (p < 0.01) possessed a significantly lower heat solubility of collagen (p < 0.01), and a different size and arrangement of collagen fibers. Sheep casings were significantly tougher than lamb casings (p < 0.01). Compared with lamb casings, sheep casings had a significantly low heat-labile collagen content, a low heat solubility of collagen, a large size of collagen fibers, and a high pyridinoline concentration (p < 0.01). Therefore, the high thermal and structural stability of collagen in aged animals may contribute to the enhanced mechanical properties of casings.

Effect of Pulsed Electric Fields (PEF) Pre-Treatment on the Quality of Sous Vide (SV) Processed Beef Short Ribs and Optimisation of PEF and SV Process Parameters Using Multiple Polynomial Regression Model

To maximise tenderness, minimise cooking loss, and decrease the adverse effects on the colour of beef short ribs, third-order multiple regression models were used to optimise the processing parameters during the pulsed electric fields (PEF) followed by sous vide (SV) processing. Electric field strength (EFS) and specific energy (SE) of PEF ranged from 0 to 0.85 kV/cm and 0 to 110.96 kJ/kg, respectively, and SV processing for 12, 24, or 36 h at 60 °C was applied. The optimum PEF-SV processing conditions for short ribs were found at EFS of 0.85 kV/cm and SE of 110.96 kJ/kg with SV processing at 60 °C for 23.96 h. In the absence of PEF pre-treatment, the optimum SV time at 60 °C was 36 h. PEF pre-treatments (SE, 99–110.96 kJ/kg) followed by SV (24 h) at 60 °C resulted in a significantly lower cooking loss (%) and texture profile analysis hardness compared to PEF at all treatment intensities, followed by SV at 60 °C for 36 h. Furthermore, significant differences were not observed in the redness, hue angle, and chroma at different PEF-SV processing parameters. Therefore, for industrial applications, PEF-SV processing with EFS (0.85 kV/cm), pulse width (20 µS), pulse frequency (50 Hz) and SE (110.96 kJ/kg), and SV temperature–time combination of 60 °C and 23.96 h is highly recommended.

3D-Printed Hybrid Collagen/GelMA Hydrogels for Tissue Engineering Applications

Bioprinting is an emerging technology involved in the fabrication of three-dimensional tissue constructs for the repair and regeneration of various tissues and organs. Collagen, a natural protein found abundantly in the extracellular matrix of several tissues, can be extracted from collagen-rich tissues of animals such as sheep, cows, rats, pigs, horses, birds, and marine animals. However, due to the poor printability of collagen bioinks, biocompatible collagen scaffolds that mimic the extracellular matrix (ECM) are difficult to fabricate using bioprinting techniques. Gelatin methacrylate (GelMA), a semi-synthetic polymer with tunable physical and chemical properties, has been found to be a promising biomaterial in various bioprinting applications. The printability of collagen can be improved by combining it with semi-synthetic polymers such as GelMA to develop hybrid hydrogels. Such hybrid hydrogels printed have also been identified to have enhanced mechanical properties. Hybrid GelMA meshes have not previously been prepared with collagen from ovine sources. This study provides a novel comparison between the properties of hybrid meshes with ovine skin and bovine hide collagen. GelMA (8% w/v) was integrated with three different concentrations (0.5%, 1%, and 2%) of bovine and ovine collagen forming hybrid hydrogels inks that were printed into meshes with enhanced properties. The maximum percentage of collagen suitable for integration with GelMA, forming hybrid hydrogels with a stable degradation rate was 1%. The water-soluble nature of ovine collagen promoted faster degradation of the hybrid meshes, although the structural crosslinking was identified to be higher than bovine hybrid meshes. The 1% bovine collagen hybrid meshes stood out in terms of their stable degradation rates.

Application of gamma radiation in the beef texture development during accelerated aging

This study aimed to evaluate the effects of gamma radiation (3 kGy) on the quality of post-rigor beef (M. longissimus lumborum) aged for up to 21 days at different temperatures (1, 7, and 15°C). Irradiation reduced the mesophilic and lactic acid bacteria counts, which were higher in the non-irradiated samples aged at 7 and 15°C. The water retention capacity was lower in the irradiated beef, resulting in higher values of exudation and cooking losses. High aging temperatures increased the exudation loss and myofibrillar proteolysis (lower fragmentation index; FI) and reduced the total and insoluble collagen contents and the beef Warner-Bratzler square Shear Force (WBsSF). However, irradiated beef had higher FI and SF than non-irradiated ones, increasing the time required for the beef tenderizing. Gamma irradiation (3 kGy) can be used to ensure the microbiological safety during short storage at high temperatures (up to 15°C) in order to accelerate the process of beef tenderizing.

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 Sous vide Processing on Quality Parameters of Beef Short Ribs and Optimisation of Sous vide Time and Temperature Using Third-Order Multiple Regression

The aim of this research was to study the effect of sous vide temperature (60, 65, and 70 °C) and time (12, 24, and 36 h) combination on the quality of beef short ribs, namely colour, cooking loss (%), shrinkage (%), soluble collagen (%), myofibrillar fragmentation index (MFI), Warner–Bratzler shear force (WBSF), and Texture Profile Analysis (TPA) parameters with different packaging materials. Aluminium and polyethylene, ethylene vinyl alcohol, and polyamide plastic laminate pouch were recommended for sous vide processing due to no detrimental effect on colour owing to its low oxygen permeability. The results showed a significant (p < 0.05) increase in shrinkage in volume (%), cooking loss (%), and the proportion of soluble collagen (%) and MFI when sous vide temperature and the processing time were increased to 70 °C and 36 h. WBSF and the TPA hardness value were significantly lower (p < 0.05) at 70 °C than at 60 °C both for 36 h due to higher level of solubilisation of collagen and myofibrillar fragmentation by prolonged heating in the moist in-pack environment and overpressure created by saturated steam. As the use of a laminate pouch reduced the oxidation of red myoglobin to brown metmyoglobin, the effect of sous vide temperature and time on International Commission on Illumination (CIE) hue angle and Chroma was not significant. Process optimisation using third-order multiple regression was conducted and the results revealed that optimum sous vide processing temperature and time combination for beef short ribs were 60 °C and 34.06 h.

Differences in Meat Quality of Six Muscles Obtained from Southern African Large-Frame Indigenous Veld Goat and Boer Goat Wethers and Bucks

Various meat quality characteristics of six muscles (Longissimus thoracis et lumborum (LTL), Semimembranosus (SM), Biceps femoris (BF), Supraspinatus (SS), Infraspinatus (IS), Semitendinosus (ST)) from large-frame Boer Goats (BG) and Indigenous Veld Goats (IVG: Cape Speckled and the Cape Lob Ear) were studied. Weaner male BG (n = 18; 10 bucks and 8 wethers) and IVG (n = 19; 9 bucks and 10 wethers) were raised on hay and natural grass, and on a commercial pelleted diet to a live weight of 30–35 kg. All goats were slaughtered at a commercial abattoir and the dressed carcasses were chilled at 4 °C within 1 h post mortem. The muscles were dissected from both sides 24 h post mortem and aged for 1 d and 4 d. Variations in meat characteristics such as ultimate pH, water holding capacity (WHC), % purge, myofibril fragment length (MFL), intramuscular fat (IMF), connective tissue characteristics, and Warner-Bratzler shear force (WBSF) were recorded across muscles. Bucks had higher lightness (L*) and hue-angle values, whereas wethers had increased redness (a*) and chroma values. The muscle baseline data will allow informed decisions to support muscle-specific marketing strategies, which may be used to improve consumer acceptability of chevon.

A comparison of Nellore and Nellore-cross entire male cattle finished in a feedlot in a tropical area of Brazil with respect to carcass characteristics and meat quality after ageing either with or without 60days of prior frozen storage

ContextThe use of crosses between Bos taurus and Bos indicus has boosted cattle production in tropical areas of Brazil, improving carcass and meat standards. However, there is little information on Canchim animals crossed with Nellore. Additionally, freezing is a preservation method frequently used by consumers, which allows meat to be preserved for a prolonged period, but little is known regarding this effect in meat frozen for 60 days from crossbred animals.AimsThe present study sought to evaluate the carcass performance and characteristics, and the effects of freezing prior to ageing on the meat of animals from different genetic groups finished in a feedlot.MethodsA total of 26 male cattle were used, consisting of Angus×Nellore (AAN), Canchim×Nellore (CAN) and Nellore (NEL), finished in feedlot. The carcasses were evaluated after slaughter. The steaks (Longissimus thoracis) were submitted to freezing for 0, 30 and 60 days before ageing, and were then aged for 1, 7 and 14 days.Key resultsConsumption and performance was greater for AAN and CAN animals. The AAN and CAN crossbred cattle presented higher final liveweight, hot carcass weight, dressing-out percentage and rib eye area. Freezing did not affect the meat luminosity, and it reduced the shear force and the purge at 14 days of ageing when frozen for 30 and 60 days.ConclusionsThe crossbreed between Canchim×Nellore animals is an alternative for termination in a feedlot. Meats frozen before ageing were more tender.ImplicationsCrossbred animals have better carcass performance and characteristics and the pre-freezing process yielded more tender meat. The Canchim is an alternative for crossing with pure Bos indicus animals.

A comparison of meat composition, tenderness and the fatty acid profile of three muscles from Holstein-Friesian bulls from production system resulting in final ages of either <16 or 19 months

Context The increased number of male dairy origin calves in Ireland due to the abolition of European Union milk quotas is a potential resource for the beef industry. Rearing these animals as bulls rather than steers is more efficient from a production perspective. Ensuring satisfactory quality of bull beef from dairy origin is essential. Aim To determine the effect of two production systems and three muscle types on physico-chemical characteristics and fatty acid (FA) profile of beef from Holstein-Friesian (HF) bulls. Methods Thirty HF bulls were equally assigned to two production systems, namely, slaughter at under 16 months of age or slaughter at 19 months of age. Longissimus thoracis (LT), Semitendinosus (ST) and Gluteus medius (GM) muscles were excised post-slaughter for determination of pH, colour, Warner–Bratzler (WB) variables, cook loss, chemical composition [intramuscular fat (IMF), moisture, protein, ash], collagen characteristics and FA profile. Results WB variables and cook loss after 14 days postmortem ageing, and insoluble and total collagen contents were higher, while IMF content, redness and saturation at 24 h post-blooming were lower for muscles from the 19-month production system. Muscles from the under 16-month production system had a higher saturated fatty acid (SFA) proportion and n-6:n-3 polyunsaturated fatty acid (PUFA) ratio, while muscle from the 19-month production system had a higher PUFA proportion, n-3 PUFA proportion and PUFA:SFA ratio. The GM muscle had the lowest L* value, followed by LT and ST. Yellowness, saturation and hue angle were greater in ST. LT had lower WB variables, cook loss, moisture, and a higher IMF content than ST and GM. The PUFA proportion and PUFA:SFA ratio were highest in ST, followed by GM and LT. IMF, total FA, SFA and monounsaturated fatty acid (MUFA) concentrations were higher in LT from the under 16-month production system bulls (the interaction). Conclusions Beef from the under 16-month production system compared with beef from the 19-month production system, and LT compared with ST and GM muscles had better quality characteristics. Implications Dairy bulls can produce beef of acceptable quality. The findings will guide selection of the combination of production system and muscle type most appropriate to specific market requirements.

Impact of genetic potential for residual feed intake and diet fed during early- to mid-gestation in beef heifers on carcass characteristics and meat quality attributes of their castrated male offspring

Carcass attributes of steers were examined for influences of selection for residual feed intake (RFI), and exposure to different levels of prenatal nutrition. Heifers characterized for RFI corrected for backfat were mated to bulls with genetic potential for either High-RFI or Low-RFI, such that the progeny were expected to be H/H or L/L RFI (sire/dam). Pregnant heifers were assigned to a low diet (Ldiet; 0.40 kg/d ADG), or moderate diet (Mdiet; 0.57 kg/d ADG), from 30 to 150 days of gestation, after which all heifers were managed similarly. Steer offspring (n = 23) were also managed similarly until slaughter. Dressing percentage of steers from H-RFI dams/sires exposed to Ldiet during gestation was lower than all other groups (P = 0.02). Marbling was greater for steers from H-RFI parents, as was fat content of longissimus thoracis et lumborum and triceps brachii (P ≤ 0.02). Results suggest that parental selection for RFI and prenatal maternal diet can influence carcass characteristics of progeny.

Physicochemical and Sensory Assessments in Spain and United States of PGI-Certified Ternera de Navarra vs. Certified Angus Beef

The physicochemical and sensory differences between the PGI-Certified Ternera de Navarra (CTNA) (Spanish origin) and Certified Angus Beef (CAB) (US origin) were assessed in Spain and the USA. To characterize the carcasses, the ribeye areas (REAs), and marbling levels were assessed in both testing places. Twenty striploins per certified beef program were used as study samples. For sensory analysis, the striploins were vacuum packaged and aged for 7 days at 4 °C and 85% RH in each corresponding laboratory. Thereafter, the samples were half cut and frozen. One of the halves was shipped to the other counterpart-testing place. The fat and moisture percentage content, Warner Bratzler Shear Force (WBSF), and total and soluble collagen were tested for all the samples. The CAB carcasses had smaller REAs (p < 0.0001) and exhibited higher marbling levels (p < 0.0001). The CAB striploins had a higher fat content (p < 0.0001) and required lower WBSF (p < 0.05) than the CTNA samples. Trained panelists rated the CAB samples as juicer (p < 0.001), more tender/less tough (p < 0.0001), and more flavorful (p < 0.0001) than the CTNA counterparts. This study shows that beef from both countries had medium-high tenderness, juiciness, and beef flavor scores and very low off-flavor scores. Relevant differences found between the ratings assigned by the Spanish and the US panelists suggest training differences, or difficulties encountered in using the appropriate terminology for defining each sensory attribute. Furthermore, the lack of product knowledge (i.e., consumption habits) may have been another reason for such differences, despite the blind sensory evaluation.

Prediction of the intramuscular connective tissue components of fresh and freeze-dried samples by near infrared spectroscopy

This study compared the performance of near-infrared spectroscopy (NIRS) models on fresh and freeze-dried beef muscle samples to predict intramuscular connective tissue (IMCT) components and to determine whether the accuracy of the models differed among different muscles from beef cattle. The hypothesis was that the water content of muscle samples would negatively influence the accuracy of the models, which would differ among muscles. Fresh and freeze-dried samples (n = 171) of four muscles were used to develop NIRS models to predict the contents IMCT. For the total collagen content, the standard error of cross validation (SECV) for model using freeze-dried samples (0.75 mg OH-prol/g DM) was lower than that for model using fresh samples (0.84 mg OH-prol/g DM). For cross-links and proteoglycans, the SECV for models using fresh sample spectra was lower than that for models using freeze-dried sample spectra. The accuracy of the prediction of the models also differed among predicted muscle types.

Liveweight and Sex Effects on Instrumental Meat Quality of Rubia de El Molar Autochthonous Ovine Breed

Simple Summary

A total of 84% of the autochthonous livestock breeds in Spain are in danger of extinction. This decline is mainly produced because they are not very productive and the farmers have been oriented to the most productive breeds, neglecting the rest. There are many factors that push us to conserve autochthonous breeds with little census. These animals are very adapted to their environment, so they are the ones that best exploit the geographical characteristics of their area; besides, their products have a high quality and these breeds have very beneficial genetic components: they are a source of very useful and not sufficiently known gene variants that make them a genetic heritage of undoubted value. If they become extinct, we would be losing an irreplaceable genetic quality. Rubia de El Molar sheep, an autochthonous breed of Madrid, Spain, is currently in serious danger of disappearing. In this work, the meat quality of lambs from Rubia de El Molar breed was studied to test both weight and sex effects on meat quality, assessed by means of instrumental methods. This is the first work that studies the instrumental quality of Rubia de El Molar suckling lamb meat.

Abstract

The effects of sex and weight on instrumental meat quality characteristics of Rubia de El Molar autochthonous ovine breed were studied. Four weight groups (10, 15, 20 and 25 kg, each of the groups with seven males and seven females) were assessed. A decrease of longissimus thoracis muscle (LT) lightness from 43.39 for 10 kg lambs to 38.84 for 25 kg group was observed. LT redness and yellowness indices and chromaticity values increased as weight increased. The percentage of juice expelled increased from 11.52 (10 kg) to 17.15 (15 kg). The percentage of intramuscular fat in biceps femoris (BF) and supraespinatus (SE) muscles increased as weight increased. Warner–Bratzler shear force (WBSF) in raw meat and hardness in cooked meat increased as liveweight increased. However, a decrease in the amount of soluble collagen in quadriceps femoris (QF), biceps femoris (BF) and infraespinatus (IE) muscles was observed as weight increased. Sex effect was only observed for intramuscular fat content in QF and BF muscles (2.4% in males and 2.9 in females) and WBSF in raw meat (26.12 N for males and 21.25 N for females). Weight had a greater effect than sex on Rubia de El Molar meat quality characteristics.

Meat quality, post-mortem proteolytic enzymes, and myosin heavy chain isoforms of different Thai native cattle muscles

OBJECTIVE

This study investigated the meat quality characteristics, endogenous proteolytic enzymes, collagen content, and myosin heavy chain (MyHC) isoforms of different muscles of Thai native cattle (TNC).

METHODS

Infraspinatus (IF), Longissimus thoracis (LT), and Supraspinatus (SS) muscles were obtained from two TNC breeds, Kho-Lan (KL, n = 7) and Kho-Isaan (KI, n = 7). The muscle and meat characteristics of TNC breeds and their relationship with MyHC expression were examined.

RESULTS

Three MyHC isoforms namely MyHC I, MyHC IIa, and MyHC IIx were detected in the muscles. The KL had higher (p<0.05) MyHC IIx than the KI. The IF muscle had higher (p<0.05) MyHC I compared to other muscles. The LT muscle had the least MyHC I. The LT had higher (p<0.05) MyHC IIx than the IF and SS muscles. The IF presented the least MyHC IIx. The KL had higher (p<0.05) lightness and moisture content and lower crude protein, redness, cooking loss, shear force, and calpastatin than the KI. The glycogen, total collagen, soluble collagen, crude protein, ash contents, and troponin T degradation product of IF and SS were lower (p<0.05) than that of LT. Ether extract in LT was lower (p<0.05) than that of IF and SS. The percentage of MyHC I, MyHC IIa, and MyHC IIx were significantly correlated with muscle and meat characteristics of TNC.

CONCLUSION

These results suggest that the differences in the MyHC isoforms may partly account for the variation in meat quality between breeds and among muscles of TNC.

Evaluating the effect of cooking temperature and time on collagen characteristics and the texture of hog maw

This study evaluated the texture of hog maw and the degradation of Types I and III collagen in the intramuscular connective tissue (IMCT) of hog maw at different cooking temperatures (75-95°C) and times (50-130 min). The cooking loss, shear force, collagen content, collagen solubility, and IMCT strength of hog maw cooked in water baths were measured. The instrumental texture profile analysis showed that the brittleness, springiness, chewiness and hardness of the cooked hog maw significantly increased with the increase of cooking temperature, while the hardness, springiness and chewiness increased first and then decreased with increasing cooking time. Cooking loss exhibited a 38% increase between the raw meat and meat cooked at 95°C. The collagen solubility significantly increased from 5.5 mg/g for raw meat to 8.6 mg/g for meat cooked at 95°C, accompanied by decreases in the shear force and IMCT strength associated with the increase in cooking temperature and time. These results show that the texture and collagen characteristics of hog maw are dramatically affected by the cooking temperature and time. Sodium dodecyl sulfate electrophoresis and immunofluorescence staining further showed that collagen degradation occurred after cooking, and the degradation of Type I collagen was higher than that of Type III collagen. These results indicated that the degradation of Type I collagen was mainly responsible for the sensory and textural improvements of the cooked hog maw.

Innovative Characterization Based on Stress Relaxation and Creep to Reveal the Tenderizing Effect of Ultrasound on Wooden Breast

In order to explore a new strategy to characterize the texture of raw meat, based on the ultrasonic tenderized wooden breast (WB), this study proposed stress relaxation and creep to determine the rheological properties. Results showed that hardness was significantly decreased from 3625.61 g to 2643.64 g, and elasticity increased, after 600 W ultrasound treatment at 20 kHz for 20 min (on-time 2 s and off-time 3 s) at 4 °C. In addition, based on the transformation of creep data, a new indicator, slope ε'(t), was innovatively used to simulate a sensory feedback of hardness from the touch sensation, proving WB became tender at 600 W treatment due to the feedback speed to external force. These above results were confirmed by the reduced shear force, increased myofibril fragmentation index (MFI), decreased particle size, and increased myofibrillar protein degradation. Histology analysis and collagen suggested the tenderizing results was caused by muscle fiber rather than connective tissue. Overall, stress relaxation and creep had a potential to predict meat texture characteristics and 600 W ultrasound treatment was an effective strategy to reduce economic losses of WB.

Effect of sous vide cooking and ageing on tenderness and water-holding capacity of low-value beef muscles from young and older animals

This study investigated the effect of the age of the animal, sous vide cooking and ageing on tenderness and water-holding capacity of bovine biceps femoris (BF) and semitendinosus (ST). Samples of each muscle from young (<18 months) and older (30-42 months) animals, at 0 and 13 days ageing, were cooked at 55 °C, 65 °C, and 75 °C for 1 h, 8 h and 18 h and tested for Warner-Bratzler shear force (WBSF), cooking loss, total water content and collagen solubility. WBSF reduced with ageing (P < 0.05) and sous vide cooking (P < 0.001) in both muscles. Our results demonstrated that meat from older animals required a higher temperature (75 °C) and prolonged cooking (18 h) to achieve equal tenderness in both BF and ST relative to young animals. Cooking time, temperature and their interaction altered cooking loss (P < 0.001) for both muscles. The higher cooking temperature increased collagen solubility (P < 0.001) in both muscles and solubilisation of collagen may have contributed to improved tenderness of BF and ST in sous vide cooking.

Texture and quality of chicken sausage formulated with woody breast meat

Woody breast (WB) myopathy is a quality defect, afflicting a large portion of commercial broilers to some degree. The WB myopathy is commonly attributed to rapid bird growth and characterized by excessive fibrosis within the pectoralis major, which is thought to cause the palpably hardened texture observed in the afflicted breast meat. These phenotypically tough breast fillets are not marketed for traditional intact muscle products owing to poor quality and eating experience. Potential avenues for these afflicted breast fillets include their use in formulation of fresh and cooked sausages. Two degrees of WB fillets (moderate and severe) were used as a replacement for normal (unafflicted) breast fillet meat at levels of 25, 50, and 100%, in a sausage formulation with 1.5% salt and 15% chicken fat. All 6 treatments were compared with a control formulation (100% normal breast meat) and analyzed for texture profile, cook loss, color, and proximate composition. Moisture and fat content for all formulations were similar (P = 0.95 and P = 0.33, respectively), but with increase in the inclusion rate of WB meat, lower protein content (P < 0.01) was observed. Raw sausage color indicated a lighter (P < 0.05) color for the control sausage (100% normal) than with both 100% moderate and 100% severe formulations. Similarly, sausages containing 100% severe WB meat were the darkest (L∗; P < 0.05), but they were similar to sausages containing 100% moderate (P > 0.05) WB meat. Texture profile analysis indicated a decrease in hardness, cohesiveness, and springiness with use of 100% severe WB meat, while inclusion of lower proportions of severe WB meat resulted in similar textural characteristics. These results indicate the possibility of using WB fillet meat in a sausage formulation with minimal impact on sausage texture profiles.

Relationship between meat quality and intramuscular collagen characteristics of muscles from calf-fed, yearling-fed and mature crossbred beef cattle

Intramuscular Ehrlich Chromogen (EC) and pyridinoline (Pyr) concentrations in the gluteus medius (GM) and semitendinosus (ST) from crossbred Angus calf- (n = 14) and yearling-fed (n = 14) steer and mature cow (MC, n = 12) carcasses were related to collagen and intramuscular connective tissue (IMCT) thermal stability and peak Warner-Bratzler shear force (WBSF). In both muscles, Pyr density was greater in MC, while EC concentrations were comparable in calf- and yearling-fed steer muscles and lowest in MC muscles. Thermal denaturation temperature and enthalpy of IMCT were highest in both muscles when from MC, although only total collagen was correlated with WBSF in calf fed-yearling fed steer data. Results confirmed that EC concentration contributed to collagen thermal stability in steer muscles, but decreased it in MC muscles, while Pyr was consistently associated with collagen thermal stability.

Studying the Effects of Collagenase (Type 1) on the Collagen in Woody Breast Meat

Abnormal collagen infiltration in the Pectoralis major, breast muscle, of fast-growing big broilers has led to woody breast (WB) myopathy resulting in meat quality issues. Mechanisms to degrade the collagen were investigated to potentially improve WB texture. Freshly deboned WB fillets (n = 5 per trial; 3 trials) were ground and divided in to 25 g portions. Aqueous collagenase Type I solution (1 mL) from concentrations of 2.5, 5, and 10 mg/mL were incorporated in ground WB samples (n = 3 samples/treatment × 3 trials). Ground WB with 1 mL water acted as a control. All the samples were placed at 4 °C for 24 h and frozen at -80 °C. Control samples without any treatment or water addition (n = 3/trial) were frozen immediately upon grinding. Data collected on total (TC), soluble (SC), and insoluble collagen (IC) content was analyzed using one-way ANOVA with Tukey's honestly significant difference (HSD) (p ≤ 0.05). Fresh WB fillets had TC, SC, and IC content of 19.5, 4.9, and 14.6 mg/g, respectively. The addition of collagenase decreased (p ≤ 0.05) the IC to 5.8 mg/g in the 10 mg/mL treatment after 24 h. Converting IC to SC using collagenase can potentially help the poultry industry to reduce WB toughness.

Influence of collagen changes on the tenderness of yak rumen smooth muscle during storage

The aim of the present study was to investigate the influence of collagen changes on the tenderness of yak rumen smooth muscle during storage. Yak rumen smooth muscle was stored at 3 ± 1 °C for 7 d and the Warner–Bratzler shear force (WBSF); total, soluble, and insoluble collagen content (TCC, SCC); collagen solubility (CS); and histological structure were monitored. Label-free mass spectrometry was used to validate the changes in collagen. Collagen changes significantly influenced yak rumen smooth muscle tenderness. A significant positive relationship was found between WBSF and TCC, SCC, as well as CS. The label-free mass spectrometry results validated that the collagen of smooth muscle was degraded during storage. Histological analysis revealed that yak rumen smooth muscle structure was destroyed during storage. Smooth muscle underwent a similar change in tenderness as skeletal muscle, and the weakening of connective tissue was the main reason for smooth muscle tenderness development.

Meat quality attributes and oxidation stability of loin chops from finishing gilts and cull sows

The objective of this study was to compare the meat quality attributes, color stability, and lipid oxidation of loin chops from finishing gilts and cull sows in a three-way crossbreeding system: landrace × large white × duroc finishing gilts (n = 20) and landrace × large white sows (n = 20). No significant differences in pH, proximate composition, or total collagen content were found between the two pig groups. However, sow loin chops exhibited different quality characteristics for color, cooking loss, protein solubility, and shear force, in which an increased cooking loss and shear force might be associated with a lower heat-soluble collagen content compared to the gilt loin chops (p < 0.05). Moreover, more rapid changes in redness and chroma during 7 days of aerobic display were observed in the sow loin chops (p < 0.05). Therefore, the results presented here highlight the possibility of issues regarding color and tenderness in sow meat compared to retail pork produced from finishing gilts.

Raw-Cured Spanish Traditional Meat Product "Chistorra de Navarra": Sensory and Composition Quality Standards

The aim of this work was to set the quality standards of the chistorra de Navarra, a raw-cured Spanish traditional meat product, through the study of its sensory and physicochemical features. The quality of chistorra samples, coming from 50 different artisan producers, were assessed during three sessions by expert assessors (n = 15). In the first session, instrumental colour (L*, a*, and b*) and appearance and odour parameters were evaluated in the raw products. In the second session, texture and flavour attributes were determined in cooked products. Finally, in the third session, the best 10 classified chistorras from the first and second sessions were sensorially evaluated and sampled for further analysis: texture (Warner Bratzler and texture profile analysis (TPA)), chemical composition, and fatty acid profile. The chistorras with the highest sensory scores had high shear force values, flavour intensity, and fat/hydroxyproline ratio. The average fatty acid profile obtained for chistorra de Navarra was: 42% saturated fatty acids (SFA), 45% monounsaturated fatty acids (MUFA), and 13% polyunsaturated fatty acids (PUFA), which was similar to the one found in other raw-cured sausages. Considering the sensory evaluation, chistorra was defined as a product with an intense orange colour, and with high resistance value in the initial bite. It was also characterised by a high juiciness and tenderness, aroma, and meat flavour. In mouth, the pork fat, one of the ingredients of chistorra, was balanced without any of the ingredients dominating. Chemically, the chistorra was characterised by a fat content close to 67% (dry matter), low hydroxyproline occurrence (≤0.6), and protein amount ranging 18–38%.

Quality traits of fresh and dry-cured loin from Iberian x Duroc crossbred pig in the Montanera system according to slaughtering age

Iberian x Duroc cross grower pigs of similar weight, but 12, 10 and 8 months of age, were finished using the Montanera system to study effects on fresh and dry cured loin quality. Pigs were slaughtered simultaneously at 16, 14 and 12 months of age (IBxD16, IBxD14 and IBxD12) and longissimus thoracis et lumborum were removed and processed into dry-cured loin. Fresh and dry cured loins from the oldest animals (IBxD16) had higher tocopherols, C18:2 n-6 and PUFA as well as higher insoluble collagen, which led to greater hardness. Fresh loin from the youngest animals (IBxD12) had the lowest myoglobin content, redness (a*), chroma and hue angle. No differences in proximate composition or instrumental colour were found in dry-cured loins.

Portuguese Local Pig Breeds: Genotype Effects on Meat and Fat Quality Traits

Simple Summary

Local breeds are generally associated with slower growth rates, higher slaughter weights, and fatter carcasses due to genetic and rearing system characteristics. When compared to intensive pig production systems, those based on European local breeds generally provide a more favourable response to the required increase in the production of high-quality pork and pork products in sustainable chains, meeting consumer demands. Reducing costs and improving the economic viability of production systems while preserving the quality of the products obtained is of vital importance. In this work, we propose that Portuguese local pig production chains could improve their performance and productivity without compromising the quality of the final product by crossing local breeds instead of crossing with modern breeds. This could help to maintain or increase local breed populations, supporting conservation of animal biodiversity.

Abstract

This work investigated the contribution of cross-breeding between two local Portuguese pig breeds to the conservation of animal biodiversity and income of local pig producers. Quality traits of semimembranosus (SM), gluteus medius (GM) and dorsal subcutaneous fat (DSF) were studied in Alentejano (AL), Bísaro (BI), AL × BI, and BI × AL (Ribatejano—RI) castrated male pigs. Pigs were reared outdoors, fed ad libitum, and slaughtered at ~65 (trial 1) and 150 kg BW (trial 2). In trial 1, AL pigs showed higher SM intramuscular fat, lower total collagen, and higher soluble collagen than BI pigs, while AL × BI and BI × AL pigs showed intermediate (NS) values. AL, AL × BI, and BI × AL pigs showed higher SM myoglobin content, and AL a more intense red colour than BI pigs. Finally, AL, AL × BI, and BI × AL showed higher total lipids in DSF than BI pigs. In trial 2, SM and DSF results were similar to those obtained in trial 1. In GM, AL and BI × AL showed higher intramuscular fat than BI and AL × BI pigs, while AL, AL × BI and BI × AL showed lower total collagen content than BI pigs. In conclusion, these results suggest that RI crosses are a productive alternative, with overall muscle and DSF traits statistically not different between AL × BI and BI × AL, and similar to those observed in AL pigs.

Performance and carcass, loin and ham quality in crossbreds from three terminal sire lines

This study was designed to compare performance, carcass and meat quality of crossbred of a hybrid sow x three sire lines, i.e. stress positive Belgian Piétrain (BP), stress negative French Piétrain (FP) and Canadian Duroc (CD). BP offspring had a significantly higher carcass yield (p < .001) and lean meat content (p < .001) in comparison with FP, which was higher than CD. BP offspring had significantly lower pH (p < .05), water-holding capacity (WHC) (p < .001) and intramuscular fat (IMF) (p < .001) content in the loin compared to FP and CD, but these meat quality parameters, with the exception of pH, were superior for CD as compared to FP. In accordance with loin quality, pH_i, pH_u, WHC and IMF of BP were significantly lower (p < .05) compared to CD in the fresh and cooked ham. Most often, FP offspring could not be differentiated from the other offspring, with the exception of cooking loss of the cooked ham. Trained and consumer taste panels resulted in no significant differences (p > .1) in sensory attributes, however, consumers preffered CD based on ranking.

Investigating the Palatability of Lamb and Beef Components Used in the Production of Pet Food for Cats

The pet food industry continues to utilise large amounts of inedible meat components from the human food industry. Although used extensively in pet food formulations and as palatants, little is known about the palatability of individual meat components. The objectives of this study were to investigate the palatability of raw meat components commonly used in the production of pet food, using acceptance and preference testing. Those examined were lung, heart, kidney, tripe, liver and mechanically deboned meat (MDM) from lamb and beef. Two-bowl acceptance tests were used to develop an overall ranking of components within each species. Two-bowl preference tests between equivalent beef and lamb components were then used to determine whether a preference was exhibited for one species over the other. For the acceptance of components from lamb and beef, liver was the most palatable within both species, with kidney equivalent to liver when testing lamb components. The MDM was identified as the least palatable component from both species. When examining the preference between equivalent components between species, cats showed preferences for lamb over equivalent beef components, except for heart and liver which showed no difference in intake between the two species. Overall, cats were able to clearly rank the palatability of different components from lamb and beef, as well as between equivalent components from the two species. Selecting highly palatable ingredients whilst still meeting pet food manufacturing guidelines may play a role in improving overall diet palatability and acceptance by cats.

Myosin heavy chain isoforms expression, calpain system and quality characteristics of different muscles in goats

Myosin heavy chain (MHC) isoforms in goat muscles and their possible relationships with meat quality have not been fully elucidated. This study characterized the MHC isoforms in different caprine muscles using sodium dodecyl sulphate glycerol gel electrophoresis (SDS-GGE). The relationships between MHC isoforms, calpain systems and meat quality characteristics of different muscles in goats were examined. Four muscles, namely infraspinatus (IF), longissimus dorsi (LD), psoas major (PM) and supraspinatus (SS) were obtained from ten Boer crossbred bucks (7-10 months old; 26.5 ± 3.5 kg, BW). The percentages of MHC I, MHC IIa and MHC IIx in SS, IF, PM and LD were 47.2, 38.3, 32.1, 11.9; 28.0, 42.1, 33.0, 36.4; and 24.8, 19.6, 34.9 and 51.7, respectively. IF and SS had higher levels of calpastatin, total collagen and insoluble collagen contents than did PM and LD. PM had longer sarcomere length than did other muscles. LD had higher collagen solubility, troponin-T degradation products and glycogen content than did other muscles. These results infer that variable fiber-type composition could account partially for the differences in the physicochemical properties of goat muscles.

Effect of spaghetti meat abnormality on broiler chicken breast meat composition and technological quality

The effects of spaghetti meat (SM) myopathy and sampling location on chicken breast meat physical traits, composition, and protein functionality were investigated using 30 normal (N) and 30 SM boneless fillets. Weight, drip loss, pH, and color traits were determined on intact fillets. Proximate composition, water holding capacity, mineral profile, SDS-PAGE, myofibrillar, and sarcoplasmic protein solubility, and emulsifying properties were assessed on both the superficial (S) and deep (D) layers of the breasts. SM fillets were heavier (P < 0.0001) and exhibited greater drip loss (P = 0.0131) and higher b* index on the skin side of the muscle (P < 0.0001). Muscle condition by layer interaction effect revealed that the superficial portion of SM fillets (SM-S) exhibited the highest moisture (P = 0.0003) and fat contents (P = 0.0011) coupled with the lowest protein (P < 0.0001) and ash contents (P = 0.0458). Total and soluble collagen amounts were higher in N-S and SM-S groups compared with N-D and SM-D (P < 0.0001). SM-S group exhibited the highest calcium (P = 0.0035) and sodium (P < 0.0001) levels. Overall, the myopathy had only minor impacts on protein profiles, while the muscle layer exerted a more remarkable effect. SM fillets exhibited higher pH but a lower myofibrillar protein solubility (P < 0.0001). Salt-induced water uptake, cooking loss, and final yield values suggested a potential impairment of water-holding capacity in SM-affected meat. Sarcoplasmic and myofibrillar emulsion activity indexes were similar between the 2 muscle conditions, but the stability of the emulsions was lower in SM meat. Overall, significant layer and muscle condition by layer effects were not observed in the functional properties of the breast meat. SM exerted a profound and negative impact on breast meat composition that led to detrimental consequences on functionality traits. Given the fundamental role of protein quality for meat processing, these data suggest that a further step toward the understanding of this myopathy should be the investigation of intrinsic protein characteristics.

Effect of visual marbling levels in pork loins on meat quality and Thai consumer acceptance and purchase intent

OBJECTIVE

We investigated visual marbling level (VML) influence on pork loin physicochemical traits, consumer palatability responses, VML liking, purchase intent, and their relationships.

METHODS

For each of five slaughtering dates, at 24-h postmortem, nine paired Duroc castrated male boneless Longissimus dorsi (LD) muscles were categorized into low (LM, score 1-2, n=3), medium (MM, score 3-4, n=3), and high (HM, score 5-6, n=3) VML. Meat physicochemical quality traits and consumer responses (n=389) on palatability and VML liking, and purchase intent were evaluated. The experiment was in RCBD. ANOVA, Duncan's multiple mean comparisons, and correlation coefficients were determined.

RESULTS

VML correspond to crude fat (r=0.91, p&lt;0.01), but both were reversely related to moisture content (r=-0.75 and -0.91, p&lt;0.01, respectively). As VML increased, ash (p&lt;0.05) and protein (p=0.072) decreased, pH and b* increased (p&lt;0.05), but drip, cooking (p&lt;0.05) and thawing (p=0.088) losses decreased. Among treatments, muscle fiber diameter, sarcomere length, total and insoluble collagen contents, L*, and a* did not differ (p&gt;0.05). Compared to the others, HM had lower collagen solubility percentage (p&lt;0.05), but similar (p&gt;0.05) Warner-Bratzler Shear Force (WBSF). No differences (p&gt;0.05) were found in juiciness, overall flavor, oiliness, and overall acceptability, but HM was more tender (p&lt;0.05) than the others. Based on VML, consumers preferred MM to HM (p&lt;0.05), while LM was similar to MM and HM (p&gt;0.05). Corresponding to VML preference (r=0.45, p&lt;0.01), consumers (83%) would (p&lt;0.01) definitely and probably buy MM, over LM (74%), and HM (68%), respectively.

CONCLUSION

Increasing VML in pork LD altered its chemical composition, slightly increased pH, and improved WHC, thereby improving its tenderness acceptability. Marbling might reduce chewing resistance, as lower collagen solubility in HM did not impact tenderness acceptability and WBSF. While HM was rated as most tender, consumers visually preferred and would purchase MM.

An analysis of the influence of various tenderising treatments on the tenderness of meat from Polish Holstein-Friesian bulls and the course of changes in collagen

The aim of the study was to analyse the influence of tenderising treatments applied to the carcasses of Polish Holstein-Friesian (PHF) bulls of Black-and-White variety on the process of meat tenderisation and to assess the role of collagen in this process. The research was carried out on m. longissimus thoracis et lumborum. The carcasses were subjected to high-voltage electrical stimulation (ES), conditioning (CD), and both treatments together (ES + CD). The carcasses which were only refrigerated were the control group. The content of collagen in meat, its solubility, the share of the polypeptide subunits α1(I)CB7 and α1(I)CB8 of type I collagen and α1(III)CB5 of type III collagen were also analysed. ES with and without CD significantly accelerated the meat tenderisation and increased collagen solubility. CD always caused the degradation of type I collagen subunits, especially the α1(I)CB7 subunit. However, CD had significantly lesser influence on the rate of meat tenderisation than ES.

Volatile Flavor Components as a Function of Electrical Stimulation and Chiller Aging for m. longissimus and biceps femoris of Hanwoo Beef

The aim of the study was to evaluate the effect of an early post-mortem low voltage electrical stimulation (ES) to localized part of carcasses [m.longissimus lumborum (LL) and m.biceps femoris (BF)] and determined the tenderness and flavor compounds of Hanwoo steers (n=16). Carcasses were stimulated within 30 min post-mortem for 60s using 60 volts and muscles aged 2 and 14 d. Degradation of Troponin-T were accelerated by ES and degraded little faster in BF muscle than LL. Level of free amino acid content of stimulated and aged muscles was significantly (p<0.05) greater than control for both muscles. Totally 63 volatile compounds were identified by using SPME-GC. The ES treatment significantly (p<0.05) affected the level of 20 volatile compounds of LL as well 15 volatiles in BF muscle along with total amounts of ketones, sulfur containing, pyrazines and furans. Low voltage ES could be applied to reduce the aging time and improve volatile flavor development by increasing important desirable volatile compounds such as 2-methylpyrazine, 2,5-dimethylpyrazines and 2-acetylthiazole etc. due to released free amino acids from protein degradation.