The color of fresh pork: Consumers expectations, underlying farm-to-fork factors, myoglobin chemistry and contribution of proteomics to decipher the biochemical mechanisms.

The color of fresh pork is a crucial quality attribute that significantly influences consumer perception and purchase decisions. This review first explores consumer expectations and discrimination regarding pork color, as well as an overview of the underlying factors that, from farm-to-fork, contribute to its variation. Understanding the husbandry factors, peri- and post-mortem factors and consumer preferences is essential for the pork industry to meet market demands effectively. This review then delves into current knowledge of pork myoglobin chemistry, its modifications and pork discoloration. Pork myoglobin, which has certain peculiarities comparted to other meat species, plays a weak role in determining pork color, and a thorough understanding of the biochemical changes it undergoes is crucial to understand and improve color stability. Furthermore, the growing role of proteomics as a high-throughput approach and its application as a powerful research tool in meat research, mainly to decipher the biochemical mechanisms involved in pork color determination and identify protein biomarkers, are highlighted. Based on an integrative muscle biology approach, the available proteomics studies on pork color have enabled us to provide the first repertoire of pork color biomarkers, to shortlist and propose a list of proteins for evaluation, and to provide valuable insights into the interconnected biochemical processes implicated in pork color determination. By highlighting the contributions of proteomics in elucidating the biochemical mechanisms underlying pork color determination, the knowledge gained hold significant potential for the pork industry to effectively meet market demands, enhance product quality, and ensure consistent and appealing pork color.

Botulinum Toxin Intervention in Cerebral Palsy-Induced Spasticity Management: Projected and Contradictory Effects on Skeletal Muscles.

Spasticity, following the neurological disorder of cerebral palsy (CP), describes a pathological condition, the central feature of which is involuntary and prolonged muscle contraction. The persistent resistance of spastic muscles to stretching is often followed by structural and mechanical changes in musculature. This leads to functional limitations at the respective joint. Focal injection of botulinum toxin type-A (BTX-A) is effectively used to manage spasticity and improve the quality of life of the patients. By blocking acetylcholine release at the neuromuscular junction and causing temporary muscle paralysis, BTX-A aims to reduce spasticity and hereby improve joint function. However, recent studies have indicated some contradictory effects such as increased muscle stiffness or a narrower range of active force production. The potential of these toxin- and atrophy-related alterations in worsening the condition of spastic muscles that are already subjected to changes should be further investigated and quantified. By focusing on the effects of BTX-A on muscle biomechanics and overall function in children with CP, this review deals with which of these goals have been achieved and to what extent, and what can await us in the future.

Multivariate relationships among pH, subcutaneous fat thickness, and color in bovine meat using canonical correlation analysis / Relación multivariada entre pH, espesor de grasa subcutánea y color en carne bovina usando el análisis de correlación canónica / Relação multivariada entre pH, espessura de gordura subcutânea e cor em carne bovina usando a análise de correlação canônica

Abstract Background: pH, subcutaneous fat thickness (SFT), and color are fundamental variables to define the organoleptic characteristics of meat. However, multivariate relationships of those traits remain unexplored in bovine meat. Objective: To investigate the multivariate relationships among pH, subcutaneous fat thickness, and color parameters in bovine meat using canonical correlation analysis. Methods: A dataset containing 173 individual records of pH, SFT, and color parameters (a*: intensity of red color, b*: intensity of yellow color, and L*: lightness) from five Brazilian beef cut types (Breed: Nellore; cuts: acém, contrafilé, fraldinha, patinho and picanha) was constructed. Multivariate relationships between color variables (a*, b*, and L*) and chemical variables (pH and SFT) were explored using the CANCORR procedure of SAS. Results: Two canonical correlations between U (a*, b*, and L*; color variables) and V (pH and SFT; chemical variables) variates were significant (p<0.01). First and second canonical correlations were 0.463 and 0.282, respectively. Canonical weights for variates were for U1: a* = 0.707, b* = 0.406, and L* = -0.039; U2: a* = 0.364, b* = -0.898, and L* = 1.234; V1: pH = -0.376 and SFT = 0.935; V2: pH = 0.927 and STF = 0.356. Conclusion: Subcutaneous fat thickness significantly affected intensity of red and yellow colors, whereas pH significantly affected lightness. The results of this study may be useful for a better understanding of the role of muscle metabolism and its implications on the organoleptic characteristics of bovine meat.

Resumen Antecedentes: El pH, espesor de la grasa subcutánea (SFT) y color, son variables importantes que definen las características organolépticas de la carne de rumiantes. Sin embargo, su relación multivariada en carne bovina permanece inexplorada hasta ahora. Objetivo: Investigar la relación multivariada entre el pH, SFT y parámetros de color en carne bovina mediante el análisis de correlación canónica. Métodos: Se construyó una base de datos con 173 registros individuales de pH, SFT y parámetros de color (a*: intensidad de color rojo, b*: intensidad de color amarillo y L*: luminosidad) de cinco tipos de cortes de carne bovina brasileña (Raza: Nellore; cortes: acém, contrafilé, fraldinha, patinho y picanha). La relación multivariada entre las variables de color (a*, b* y L*) y las variables químicas (pH y SFT) se exploró usando el procedimiento CANCORR de SAS. Resultados: Dos correlaciones canónicas entre las variables U (compuesta por a*, b* y L*; variables de color) y V (compuesta por pH y SFT; variables químicas) fueron significativas (p<0,01). La primera y la segunda correlación canónica fueron 0,463 y 0,282, respectivamente. Los pesos canónicos para las variables canónicas fueron para U1: a* = 0,707, b* = 0,406 y L* = -0,039; U2: a* = 0,364, b* = -0,898 y L* = 1,234; V1: pH = -0,376 y SFT = 0,935; V2: pH = 0,927 y SFT = 0,356. Conclusión: El espesor de grasa subcutánea afectó significativamente la intensidad de los colores rojo y amarillo, mientras que el pH afectó significativamente la luminosidad. Los resultados de este estudio pueden ser útiles para comprender el papel del metabolismo muscular y sus implicaciones en las características organolépticas de la carne bovina.

Resumo Antecedentes: O pH, a espessura da gordura subcutânea (SFT) e a cor, são variáveis importantes que definem as características organolépticas da carne de ruminantes. No entanto, sua relação multivariada em carne bovina até o momento permanece inexplorada. Objetivo: Investigar a relação multivariada entre o pH, SFT e os parâmetros de cor em carne bovina, utilizando a análise de correlação canônica. Métodos: Foi construído um banco de dados contendo 173 registros individuais de pH, SFT e parâmetros de cor (a*: intensidade de cor vermelha, b*: intensidade de cor amarela y L*: luminosidade) de cinco tipos de cortes de carne bovina brasileira (Raça: Nellore; cortes: acém, contrafilé, fraldinha, patinho e picanha). A relação multivariada entre variáveis de cor (a *, b * e L*) e variáveis químicas (pH e SFT) foi explorada usando o procedimento CANCORR do SAS. Resultados: Duas correlações canônicas entre as variáveis U (composta de a *, b * e L *, variáveis de cor) e V (composta de pH e SFT, variáveis químicas) foram significativas (p<0,01). A primeira e segunda correlação canônica foram 0,463 e 0,282, respectivamente. Os pesos canônicos para as variáveis canônicas foram para U1: a* = 0,707, b* = 0,406 e L* = -0,039; U2: a* = 0,364, b* = -0,898 e L* = 1,234; V1: pH = -0,376 e SFT = 0,935; V2: pH = 0,927 e SFT = 0,356. Conclusão: A espessura de gordura subcutânea afetou significativamente a intensidade das cores vermelha e amarela, enquanto o pH afetou significativamente a luminosidade, em carne bovina. Os resultados deste estudo podem ser úteis para entender melhor o papel do metabolismo muscular e suas implicações nas características organolépticas da carne bovina.

Historical Perspective: Heat production and chemical change in muscle. Roger C. Woledge.

The objective of this article is to provide an historical perspective on a review of "Heat production and chemical change in muscle" written by Roger C. Woledge and published in Progress in Biophysics and Molecular Biology 50 years ago. We first provide a brief but broad summary of the history of muscle chemistry prior to 1971 and then address the central theme of the 1971 review - that of energy balance. Energy balance is a method to establish whether all the energetically significant biochemical reactions accompanying muscle contraction have been identified. Woledge adopted the method to compare the measured enthalpy output (i.e., the sum of the heat output and work output) to that expected from the extent of known biochemical reactions. Prior work had suggested that the observed and expected enthalpy outputs were similar but Woledge proposed that the expected heat had been overestimated and that, hence, there must be an unidentified reaction that accounted for as much as half the heat produced by a contracting muscle. We describe investigations carried out after the review that vindicated that view, ultimately characterising the processes producing the unexplained enthalpy which, in turn, led to identification of the hitherto unknown reaction. Those experiments and a more recent resurrection of the approach using fluorescent probes to monitor ATP turnover have now accounted for the processes that underlie the complex time courses of muscle heat production and ATP turnover during contraction, at least in the classical frog sartorius muscle preparation. However, the few studies performed on mammalian muscles since then have produced results that are difficult to reconcile with the ideas derived from energy balance studies of amphibian and fish muscles, thereby suggesting a new objective for energy balance studies.

The effect of plant bioactive compounds on lamb performance, intake, gastrointestinal parasite burdens, and lipid peroxidation in muscle.

Plant extracts have been widely used in animal production systems due to the benefits promoted by their bioactive components, mainly through their antioxidant effects and positive effects on animal growth, health, and meat quality. We determined whether bioactive compounds (BC) from grape (Vitis vinifera), olive (Olea europaea), and pomegranate (Punica granatum) have beneficial effects on lamb growth while controlling gastrointestinal parasitism and reducing skeletal lipid peroxidation in muscle. Fourteen lambs (4 to 5 mo of age) were housed in individual pens and assigned to two treatment groups (seven animals/group), where they received: 1) a basal diet of beet pulp:soybean meal (90:10) (CONTROL) and 2) the same diet, but containing 0.3% of BC extracted from grape, olive, and pomegranate (BNP). After 21 d of consuming their respective rations (period 1), all lambs were dosed with 10,000 L3 stage larvae of Haemonchus contortus. Intake, production, and physiological parameters were determined before infection (period 1), after oral dosage with L3 (period 2), and during early (period 3) and later (period 4) developmental stages of infection. Groups of animals did not differ in their ration intake or average daily gain, either before or after the infection, or in their parasitic burdens estimated through fecal egg counts (P > 0.05). Lambs under BNP showed greater feed efficiency before infection (P < 0.001), but the pattern reversed after infection. In addition, the inclusion of plant bioactives to the diet did not have an effect (P > 0.05) on blood or lipid peroxidation in muscle or on hemogram, serum concentration of haptoglobin, and immunoglobulin E. These results could be explained by low dietary doses and constrained absorption or ruminal inactivation of these compounds. Changes in feed efficiencies suggest a negative interaction between BC in the diet and parasitism, which warrants further research.

Current Advances in Meat Nutritional, Sensory and Physical Quality Improvement.

Meat is an important source of proteins, vitamins, minerals and fat, and these nutrients are important for their beneficial effects on human health. In recent years, meat quality has become a more relevant topic for consumers with regard to health and sensory characteristics, and for beef industry stakeholders because it affects their profitability. Therefore, the control of meat quality, including technological, sensory and nutritional quality traits, constitutes an important target for any farm animal production. What those qualities are and how we best evaluate them at the different levels of the continuum from the farm to fork are critical to understanding meat production and consumption patterns. However, despite the efforts of the industrials to control the eating and nutritional quality traits of meat and meat products, there remains a high level of variability, which is one reason for consumer dissatisfaction. This Special Issue focuses on the study of continuum aspects from farm to fork, which would have an impact on the control of the nutritional, sensory and technological aspects of carcass, muscle, meat and meat-product qualities. It groups fourteen original studies and one comprehensive review within five main topics that are (i) production systems and rearing practices, (ii) prediction of meat qualities, (iii) statistical approaches for meat quality prediction/management, (iv) muscle biochemistry and proteomics techniques and (v) consumer acceptability, development and characterisation of meat products.

Beyond body size: muscle biochemistry and body shape explain ontogenetic variation of anti-predatory behaviour in the lizard Salvator merianae.

Anti-predatory behaviour evolves under the strong action of natural selection because the success of individuals avoiding predation essentially defines their fitness. Choice of anti-predatory strategies is defined by prey characteristics as well as environmental temperature. An additional dimension often relegated in this multilevel equation is the ontogenetic component. In the tegu Salvator merianae, adults run away from predators at high temperatures but prefer fighting when it is cold, whereas juveniles exhibit the same flight strategy within a wide thermal range. Here, we integrate physiology and morphology to understand ontogenetic variation in the temperature-dependent shift of anti-predatory behaviour in these lizards. We compiled data for body shape and size, and quantified enzyme activity in hindlimb and head muscles, testing the hypothesis that morphophysiological models explain ontogenetic variation in behavioural associations. Our prediction is that juveniles exhibit body shape and muscle biochemistry that enhance flight strategies. We identified biochemical differences between muscles mainly in the LDH:CS ratio, whereby hindlimb muscles were more glycolytic than the jaw musculature. Juveniles, which often use evasive strategies to avoid predation, have more glycolytic hindlimb muscles and are much smaller when compared with adults 1-2 years old. Ontogenetic differences in body shape were identified but marginally contributed to behavioural variation between juvenile and adult tegus, and variation in anti-predatory behaviour in these lizards resides mainly in associations between body size and muscle biochemistry. Our results are discussed in the ecological context of predator avoidance by individuals differing in body size living at temperature-variable environments, where restrictions imposed by the cold could be compensated by specific phenotypes.

Surface-enhanced Raman spectral biomarkers correlate with Ankle Brachial Index and characterize leg muscle biochemical composition of patients with peripheral arterial disease.

Peripheral arterial disease (PAD) is characterized by atherosclerotic blockages of the arteries supplying the lower extremities, which cause a progressive accumulation of ischemic injury to the skeletal muscles of the lower limbs. This injury includes altered metabolic processes, damaged organelles, and compromised bioenergetics in the affected muscles. The objective of this study was to explore the association of Raman spectral signatures of muscle biochemistry with the severity of atherosclerosis in the legs as determined by the Ankle Brachial Index (ABI) and clinical presentation. We collected muscle biopsies from the gastrocnemius (calf muscle) of five patients with clinically diagnosed claudication, five patients with clinically diagnosed critical limb ischemia (CLI), and five control patients who did not have PAD. A partial least squares regression (PLSR) model was able to predict patient ABI with a correlation coefficient of 0.99 during training and a correlation coefficient of 0.85 using a full cross-validation. When using the first three PLS factor scores in combination with linear discriminant analysis, the discriminant model was able to correctly classify the control, claudicating, and CLI patients with 100% accuracy, using a full cross-validation procedure. Raman spectroscopy is capable of detecting and measuring unique biochemical signatures of skeletal muscle. These signatures can discriminate control muscles from PAD muscles and correlate with the ABI and clinical presentation of the PAD patient. Raman spectroscopy provides novel spectral biomarkers that may complement existing methods for diagnosis and monitoring treatment of PAD patients.

Chemical composition and structural characteristics of Arabian camel (Camelus dromedarius) m. longissimus thoracis.

Saudi Arabian camels of four breeds (6 animals per breed) were used to evaluate characteristics and quality of their meat. Chemical composition, fibre cross sectional area, collagen content, muscle metabolism, cooking loss, pH at 24 h post mortem, colour values (except redness) and shear force of Longissimus thoracis (LT) muscle did not differ between the breeds. Elevated pH values and short sarcomeres reduced overall tenderisation, with a difference between myofibril fragmentation index (P<0.001) and sarcomere length (P<0.05) between breeds. A positive correlation was observed between the activities of the mitochondrial enzymes (r>0.49), between the glycolytic activities (PFK and LDH) (r=0.61) and between Myosin Heavy Chain IIa and LDH activity. The intramuscular fat content was positively associated with redness and muscle oxidative metabolism, whereas shear force had a slight positive association with collagen content and muscle glycolytic metabolism and a negative association with muscle oxidative metabolism and muscle fibre area.