Spelling suggestions: "subject:"quadriceps""
21 |
Intra and inter-rater reliability of triceps surae morphological and mechanical properties in healthy subjectsSonda, Francesca Chaida January 2018 (has links)
O tendão de Aquiles e os músculos flexores plantares têm um papel fundamental em atividades de vida diária como o levantar de uma cadeira, durante a marcha e o salto. Mudanças na sobrecarga mecânica podem levar tanto a adaptações benéficas nas propriedades mecânicas e morfológicas da unidade músculo-tendão do tríceps sural, como após o exercício físico sistematizado, quanto à perda da estrutura e da funcionalidade, como ocorre na ruptura total do tendão de Aquiles e no envelhecimento. A avaliação das propriedades estruturais e mecânicas do tríceps sural é fundamental para que se possa identificar a perda da condição de saúde, assim como também as melhoras decorrentes do processo de recuperação das estruturas musculoesqueléticas durante um programa de reabilitação. Para tanto, é fundamental que a metodologia empregada para a avaliação das propriedades estruturais e mecânicas da unidade músculo-tendínea do tríceps sural seja confiável, e que os resultados não sejam influenciados pelo avaliador (boa reprodutibilidade inter-avaliador) ou pelo dia e horário de avaliação (boa reprodutibilidade intra-avaliador). Entretanto, ainda faltam evidências na literatura referentes à obtenção de variáveis psicométricas relacionadas à avaliação das propriedades mecânicas e morfológicas do tendão de Aquiles e da arquitetura muscular dos flexores plantares em sujeitos saudáveis. Nessa perspectiva, a presente dissertação apresenta três estudos, a fim de atingir os seguintes objetivos: (Estudo 1) verificar a reprodutibilidade intra e inter-avaliador da arquitetura muscular dos flexores plantares em indivíduos saudáveis. (Estudo 2) Verificar a reprodutibilidade intra e inter-avaliador da morfologia tendínea do tendão de Aquiles em indivíduos saudáveis (Estudo 3) Verificar a reprodutibilidade intra e inter-avaliador das medidas da capacidade de produção de força do tríceps sural. Os três estudos foram realizados no Setor de Plasticidade Neuromuscular do LAPEX da ESEFID-UFRGS. Todos os participantes foram avaliados nos parâmetros de arquitetura muscular dos flexores plantares (comprimento de fascículo, ângulo de penação e espessura muscular) e do tendão de Aquiles (área de seção transversa e comprimento do tendão total livre) por meio de ultrassonografia musculo esquelética. Contrações voluntárias máximas isométricas foram realizadas em um dinamômetro isocinético. As avaliações ocorreram em 2 momentos distintos: dia 1 e dia 2 pelo avaliador 1 (7 dias de intervalo entre as coletas), e posteriormente dia 2 pelos avaliadores 1, 2 e 3 de forma sucessiva. A análise dos dados foi realizada no software SPSS v. 20.0, por meio de estatística descritiva (média, DP - desvio padrão) e inferencial (CCI – Coeficiente de Correlação Intraclasse; EPM – Erro Padrão entre Medidas = DP√(1-CCI); MMD – Mínima Mudança Detectável = 1,96*EPM), e intervalo de confiança. No estudo 1 verificamos uma alta correlação intra e inter-avaliador para espessura muscular, ângulo de penação e comprimento do fascículo dos flexores plantares (CCI>75), e valores baixos de EPM e MMD. No estudo 2, verificamos uma alta correlação intra e inter avaliador para comprimento do tendão total e área de secção transversa (CCI>75) Entretanto, para a variável de tendão livre, a correlação inter avaliador foi pobre (CCI: 0,580). Comparando a experiência dos avaliadores, os avaliadores 1 e 2 obtiveram um CCI de 0,910, enquanto que entre os avaliadores 1 e 3 o CCI foi de 0,340, e entre os avaliadores 2 e 3 o CCI foi de 0,280. Essas correlações muito baixas para a variável do tendão livre podem ser explicadas pela diferente experiência dos avaliadores e pelo tempo de treinamento na obtenção das medidas. No estudo 3, verificamos uma alta correlação intra e inter-avaliador para os valores de torque isométrico em rampa dos músculos flexores plantares (CCI>90), e valores baixos de EPM e MMD. Conclui-se, a partir dos estudos acima, que existe uma alta confiabilidade das medidas de arquitetura muscular e tendínea e de força tanto intra-avaliador quanto inter-avaliador. Além disso, os dados poderão servir como banco de dados de uma condição de saúde para comparação com dados de pacientes que sofreram lesões no tendão de Aquiles. A metodologia também pode ser aplicada na avaliação de pacientes. Entretanto, alguns aprimoramentos nas técnicas utilizadas são necessários a fim de melhorar a reprodutibilidade e reduzir ainda mais os erros de medida. / The Achilles tendon and the plantar flexor muscles play a key role in daily life activities such as raising from a chair, during gait and jump. Changes in mechanical overload can lead to both beneficial adaptations in the mechanical and morphological properties of the triceps surae muscle-tendon unit, such as after systemic exercise, as well as after the loss of structure and functionality after total Achilles tendon rupture and aging. The evaluation of the triceps surae structural and mechanical properties is fundamental so that losses in the health condition can be identified, as well as the improvements resulting from the recovery process of the musculoskeletal structures during a rehabilitation program. Therefore, it is fundamental that the methodology used to evaluate the structural and mechanical properties of the triceps surae muscle-tendon unit is reliable, and that the results are not influenced by the evaluator (high inter-rater reliability) or by the day and time of evaluation (high intra-rater reliability). However, there is still a lack of evidence in the literature regarding the psychometric variables related to the evaluation of the mechanical and morphological properties of the Achilles tendon and the plantar flexors muscular architecture in healthy subjects. In this perspective, the present dissertation presents three studies in order to achieve the following objectives: (Study 1) To verify the intra- and inter-rater reliability of the plantar flexors muscle architecture in healthy individuals. (Study 2) To verify intra- and inter-rater rater Achilles tendon morphology evaluation in healthy individuals. (Study 3) To verify intra and inter-rater reliability of the triceps surae isometric strength measurements The three studies were performed at the Neuromuscular Plasticity Sector of LAPEX of ESEFID-UFRGS. All participants were evaluated in their triceps surae muscle architecture (fascicle length, pennation angle and muscle thickness) and the Achilles tendon (cross-sectional area, tendon length and free tendon length) parameters by means of skeletal muscle ultrasonography. Maximal isometric voluntary contractions were performed on an isokinetic dynamometer. The evaluations occurred in 2 different moments: day 1 and day 2 by evaluator 1 (7-days interval between collections), and on the second day by 2 additional evaluators (2 and 3) in a successive way. Data analysis was performed in SPSS v. 20.0, by means of descriptive statistics (mean, SD - standard deviation) and inferential analysis (ICC - Intraclass Correlation Coefficient - SEM - Standard Error between Measures = DP√ (1 - ICC) MDC – Minimum Detectable Change = 1.96*EPM), and confidence interval analysis. In study 1, we verified a high intra- and inter-rater correlation for muscle thickness, pennation angle and fascicle length (ICC> 75), and low SEM and MDC values. In study 2, we found a high intra- and inter-rater correlation for total tendon length and cross-sectional area (ICC> 75). However, for the free tendon variable, the inter-rater correlation was low (ICC: 0.580). Comparing the evaluators' experience, evaluator 1 and 2 obtained a ICC of 0.910, whereas evaluators 1 and 3 had an ICC of 0.340, while between evaluators 2 and 3 the ICC was 0.280 These very low correlations for the free tendon variable can be explained by the evaluators' experience and by the training of the measurements. In study 3, we verified a high intra- and inter-rater correlation for isometric torque values of the plantar flexor muscles (ICC> 75), and low SEM and MDC values. Based on the above evidences, we can conclude that there is a high intra-rater and inter-rater reliability for muscle architecture, tendon structure and plantar flexor strength. In addition, our data can be used as a data base for the healthy condition for the comparison with patients with Achilles tendon injury. Our methodology can also be used in patients’ evaluation. However, some improvements in the used techniques are necessary to improve reliability and further reduce measurement errors.
|
22 |
Le rôle fonctionnel du triceps sural durant la marcheHoneine, Jean-Louis 22 November 2013 (has links) (PDF)
La marche humaine nécessite la génération de force propulsive ainsi que des forces antigravitaires pour maintenir l'équilibre. Pour cela, le système nerveux central est requis d'orchestrer la contraction des muscles des membres inférieurs, notamment les fléchisseurs plantaire de la cheville qui interface entre le sol et le corps humain. Durant la première phase de simple appui, le triceps sural (TS) est en contraction excentrique et son activation aide à soutenir le corps en résistant à la rotation du tibia sur le Tarsus. Par contre, la phase finale de simple appui est marquée par une augmentation des forces de réactions au sol " Push-off ", du couple articulaire de la cheville et de l'activité électromyographique du TS. Le rôle du TS durant la phase finale de simple appui est l'objet de débat dans la littérature, où certains lui attribut le rôle de propulseurs et d'autre de soutien du corps. Dans ce travail, nous postulons que l'augmentation de l'activité du TS en phase finale de simple d'appui sert uniquement à décélérer la chute du centre de masse. En outre, nous postulons que la modulation temporelle de l'activité du TS permet de contrôler la cinématique (cadence et longueur de pas) et la cinétique de la marche. Deux études ont été mises en places pour tester les hypothèses de travail. Des données biomécaniques mesurées à partir d'une plateforme de force et l'activité EMG du soléaire et des gastrocnémiens latéral et médial de la jambe d'appui ont été collecté pour les deux études. Dans la première études des volontaires ont initié la marche sans et avec un ajout de poids de 20 kg attaché au niveau de la ceinture abdominale. L'ajout du poids augmente les forces de propulsion. Une augmentation de l'activité EMG du triceps permettrait de comprendre si le triceps participe à la génération de force propulsive. La deuxième étude est composée de deux expérimentations. Dans la première expérimentations des volontaires ont accompli 3 conditions de initiation de marche à vitesse variée tout en maintenant la longueur de pas constante. Dans la deuxième expérimentation, les sujets ont été incliné et instruit de récupérer leur équilibre en exécutant un pas de longueur différente. Les résultats ont montré que : 1) le triceps ne participe pas au push-off mais freine la chute du centre de masse en phase finale de simple appui. 2) L'amplification d'activité électromyographique durant la marche rapide est due à l'augmentation de demande de support de corps causé par la croissance des forces inertiels du corps. 3) La durée de contraction du TS permet de déterminer la cadence et la longueur de pas, donc la cinématique de la marche. La durée d'activité du TS permet aussi de déterminer la position du centre de masse par rapport au centre de pression au moment du contact avec le sol. 4) Ceci permet au TS de moduler le couple de déséquilibre responsable des forces propulsives, donc la cinétique de la marche.
|
23 |
Pacote de gelo e imersão em água gelada afetam o desempenho muscular e a atividade eletromiográficaVieira, Amilton 30 March 2012 (has links)
Made available in DSpace on 2016-06-02T19:22:55Z (GMT). No. of bitstreams: 1
4273.pdf: 640166 bytes, checksum: 0c9fc1f3e1c6ddb8472d73914461506a (MD5)
Previous issue date: 2012-03-30 / Universidade Federal de Sao Carlos / Although tissue cooling is widely used in the treatment of musculoskeletal disorders there is still controversy about its effects on muscular performance. It is important to study this issue since cooling is also combined with exercise. Objective. To compare the effects of ice pack and cold water immersion on the muscular performance parameters of plantar flexors and electromyography (EMG) activity of the triceps surae. Design. Subjects were randomly assigned treatment with either ice pack (n=20) or cold water immersion (n=21). Independent variables were cold modality (ice pack or cold water immersion), muscle action (isometric and concentric isokinetic, angular velocity of isokinetic test (60 and 120°/s) and measurement time (pre- and post-cooling). Dependent variables were skin temperature, muscular performance and EMG activity. Methods. The sample included 41 healthy men with a mean age of 22.15 (SD=2.89). In each group one of the two cold modalities was applied to the calf region for 20 minutes. Skin temperature, plantar flexors muscular performance parameters and EMG activity of the triceps surae were measured before and after cooling. Results. Ice pack increased isometric peak torque. Both cold modalities reduced EMG activity in both muscles during isometric contraction. Both cold modalities reduced peak torque and total work during isokinetic contraction at both velocities. Ice pack was more effective at reducing EMG activity in isokinetic contractions. Limitations. The examiner was not blinded regarding treatment group and the population included only young healthy participants. Conclusions. Ice pack and cold water immersion showed similar effects on muscular performance, which depends on the muscle action performed. Cooling decreased isokinetic performance and the ice pack increased isometric torque. The results suggest that caution is required when performing activities after cooling, especially tasks involving maximal isokinetic contractions. / Embora o resfriamento tecidual seja amplamente utilizado no tratamento de lesões músculo esqueléticas há ainda controvérsias sobre seus efeitos no desempenho muscular. Estudar esse aspecto é importante uma vez que o resfriamento também é utilizado associado a exercícios físicos. Objetivo: Comparar os efeitos do pacote de gelo e da imersão em água gelada sobre parâmetros do desempenho muscular dos flexores plantares e atividade eletromiográfica (EMG) do tríceps sural. Desenho: Foi realizado um estudo experimental com distribuição aleatória dos participantes em dois grupos de intervenção, pacote de gelo (n=20) e imersão em água gelada (n=21). As variáveis independentes foram grupo experimental (pacote de gelo ou imersão em água gelada), tipo de contração (isométrica ou isocinética concêntrica), velocidade angular do teste isocinético (60 e 120°/s) e tempo de mensuração (pré- e pós-resfriamento). Variáveis dependentes foram temperatura da pele, parâmetros de desempenho muscular e atividade EMG. Métodos: Quarenta e um homens saudáveis, com média de idade (DP) de 22,15 (2,89) anos participaram do estudo. Cada grupo recebeu uma das duas modalidades de resfriamento, aplicada sobre a região da panturrilha por 20 minutos. A temperatura da pele e parâmetros do desempenho muscular dos flexores plantares e da atividade EMG dos músculos sóleo e gastrocnêmio medial e lateral foram avaliados antes e imediatamente após o resfriamento. Resultados: O pacote de gelo causou aumento no pico de torque isométrico. A atividade EMG foi reduzida em ambos os músculos sóleo e gastrocnêmio pelas duas modalidades de resfriamento durante a contração isométrica. As duas modalidades de resfriamento reduziram o pico de torque e trabalho total na contração isocinética em ambas as velocidades avaliadas. De modo geral, o pacote de gelo foi mais efetivo para reduzir a atividade EMG na contração isocinética. Conclusões: O pacote de gelo e a imersão em água gelada mostram efeitos similares sobre o desempenho muscular, o qual é dependente a ação muscular realizada. O resfriamento muscular diminui o desempenho durante a contração isocinético e o pacote de gelo aumenta o torque isométrico. Os resultados sugerem cautela quando forem realizadas atividades dinâmicas após o resfriamento, especialmente durante contrações isocinéticas máximas.
|
24 |
Důsledky vynucené hypokineze na pohybový aparát člověka / Consequences of forced hypokinesia on human movement apparatusKadlecová, Jana January 2014 (has links)
Title: Consequences of forced hypokinesia on human movement aparatus. Objectives: The aim of this study was to find out the influence of forced hypokinesia after total hip replacement on the excitability of α motoneurons. I deal with the changes of H-reflex and M-wave latencies and the changes of the recruitment curves. The results of the operated and non-operated (kontrol) lower limb were compared. Methods: Five volunteers 3 - 4 weeks after total hip replacement participated in this study. The age was 62,4 (± 3,01). The H-reflex was elicited by stimulation of tibial nerve in a poplitel fossa. The H-reflex and M-wave latencies and its recruitment curves were obtained. After that the values of the operated lower limb were compared with the non-operated one (control). The results were evaluated as case studies. The EMG device Grass Telefactor was used to detect the electrical potential of soleus muscle. The rectangular pulses of 0,5 ms duration were used for stimulation tibial nerve by Grass 88 Stimulator. Then the data were transduced by CED Power 1401 device. Results: We found out that the H-reflexes of both lower limbs were not elicited in the case study no. 2 and the H-reflex of a control lower limb was not elicited in case study no. 1. The stimulus intensities for eliciting H-reflex and M-wave...
|
25 |
Efeito da suplementação com extrato de chá verde sobre o dano muscular e dor muscular de início tardio / Effect of green tea supplementation on muscle damage and muscle sorenessSilva, Willian da January 2017 (has links)
Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2018-09-27T17:10:28Z
No. of bitstreams: 1
WILLIAN DA SILVA.pdf: 1484606 bytes, checksum: b09c4375bb0dae5662922161c28677b5 (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2018-09-27T17:10:44Z (GMT) No. of bitstreams: 1
WILLIAN DA SILVA.pdf: 1484606 bytes, checksum: b09c4375bb0dae5662922161c28677b5 (MD5) / Made available in DSpace on 2018-09-27T17:10:44Z (GMT). No. of bitstreams: 1
WILLIAN DA SILVA.pdf: 1484606 bytes, checksum: b09c4375bb0dae5662922161c28677b5 (MD5)
Previous issue date: 2017 / O extrato de chá verde possui potencial antioxidante e anti-inflamatório, que pode contribuir para recuperar o equilíbrio metabólico e estresse oxidativo pós-exercício intenso, colaborando assim para diminuir episódios de dor muscular de início tardio (DMIT). Neste estudo, buscamos determinar os efeitos da suplementação com extrato de chá verde sobre a DMIT, dano muscular e oxidativo e status antioxidante. Em um ensaio randomizado, triplo cego, placebo controle, 20 homens não treinados com idade média de 24 (±5) anos realizaram exercício para indução da DMIT no tríceps sural antes e depois de 15 dias de suplementação com extrato de chá verde (500 mg/dia) (GT, n=10) ou placebo (PL, n=10). A DMIT foi determinada pela escala visual analógica de dor (pré e pós-suplementação) antes, imediatamente após e 48 horas após o exercício. Amostras sanguíneas foram tomadas para determinar marcadores bioquímicos de dano muscular como creatina quinase (CK), lactato desidrogenase (LDH) e marcadores de estresse oxidativo como níveis de malondialdeido (TBARS), produção de espécies reativas de oxigênio (DCFH-DA), juntamente com a carbonilação de proteínas e status antioxidante como capacidade antioxidante total do plasma (FRAP) e atividade da glutationa (GSH) além da atividade da acetilcolinesterase (AChe). O exercício induziu DMIT e a suplementação com GT reduziu um marcador de dano estrutural (CK), mas não atenuou a DMIT e marcadores de estresse oxidativo e status antioxidante. Este efeito protetivo ao dano estrutural interessa especialmente ao uso desta suplementação como possível fator adjunto para a prevenção de dano muscular e auxílio na recuperação de esforços intensos. / Green tea extracts supplementation (GT) is recognized as a source of antioxidants and anti-inflammatory substances that may contribute to the recovery after intense exercise when muscle soreness (MS) occurs. In this study we determine the effects of GT on MS, muscle damage, oxidative stress and antioxidant status. Here we present a randomized trial triple blind placebo control including 20 adults aged 25 (5) years and physically active that underwent sessions exercise for induction of muscle damage in the triceps sural before and after 15 days of supplementation with GT at dose of 500 mg/day (GT, n=10) or placebo (PL, n=10). MS was determined using a visual analogic scale. Blood samples were collected to determination of biochemical markers of damage considering activity of creatine kinase (CK) and lactate dehydrogenase (LDH), oxidative stress considering levels of malondialdehyde (TBARS), reactive species of oxygen (DCFH), protein carbonylation, and antioxidant status considering total antioxidant capacity (FRAP), glutathione activity (GSH), and acetylcholinesterase (AChE) activity. Exercise induced MS and GT reduces a marker of structural muscle damage without effects on oxidative stress and antioxidant status. This protective effect may be support the use of this supplementation as a possible correlate strategy to prevent muscle damage and therefore contribute to the recovery of intense exercise.
|
26 |
Nutritional characteristics of New Zealand export lamb and functional properties of selected beef forequarter muscles : a thesis presented in partial fulfilment of the requirements for the degree of Masters of technology in Bioprocess Engineering at Massey University, Palmerston North, New ZealandJansen, Eion January 2001 (has links)
Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.
|
27 |
Nutritional characteristics of New Zealand export lamb and functional properties of selected beef forequarter muscles : a thesis presented in partial fulfilment of the requirements for the degree of Masters of technology in Bioprocess Engineering at Massey University, Palmerston North, New ZealandJansen, Eion January 2001 (has links)
Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.
|
28 |
Nutritional characteristics of New Zealand export lamb and functional properties of selected beef forequarter muscles : a thesis presented in partial fulfilment of the requirements for the degree of Masters of technology in Bioprocess Engineering at Massey University, Palmerston North, New ZealandJansen, Eion January 2001 (has links)
Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.
|
29 |
Nutritional characteristics of New Zealand export lamb and functional properties of selected beef forequarter muscles : a thesis presented in partial fulfilment of the requirements for the degree of Masters of technology in Bioprocess Engineering at Massey University, Palmerston North, New ZealandJansen, Eion January 2001 (has links)
Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.
|
30 |
Nutritional characteristics of New Zealand export lamb and functional properties of selected beef forequarter muscles : a thesis presented in partial fulfilment of the requirements for the degree of Masters of technology in Bioprocess Engineering at Massey University, Palmerston North, New ZealandJansen, Eion January 2001 (has links)
Richmond Ltd. has recently undergone a change in strategy, away from the traditional commodity based meat industry, towards the modern food business. To do this, opportunities to add value to their current product range must be identified. This involves the conversion of traditionally low value commodity based products into products that demand a premium. An example of this is converting muscles that are currently used for grinding meat into a further processed convenience food (i.e. ready meals). Another method is to add further value to premium products by making them more appealing to consumers (i.e. nutritional information on labels). This work details investigations into the functional properties of selected beef forequarter muscles (low value commodity products) and the nutritional properties of selected export lamb products (premium products). The functional properties of a number of beef forequarter muscles were measured to identify which had the best potential for further processing applications with respect to ready meals. The functional properties of tenderness, cook loss and shrinkage were measured for the Latissimus Dorsi, Pectorialis Profundus (Point End Brisket), Infraspinatus (Cross Cut Blade), Triceps Brachi Longhead (Main muscle in Bolar Shoulder Clod), Supraspinatus (Chuck Tender), Serratus Ventralis and Triceps Brachi Medialhead (Muscle in Bolar Shoulder Clod. From the tests conducted the Infraspinatus and the Triceps Brachi Longhead have been identified as having the best functional properties with respect to further processing for ready meal applications. As well as conducting tests to identify the forequarter muscles with the best potential for further processing applications, investigations were carried out to identify cooking regimes that would optimise the functional properties. This work confirmed that there are three major chemical reactions, which determine the resultant functional properties of cooked meat. They are the denaturation and aggregation of the myofibrillar proteins and the denaturation and solubilisation of connective tissue (collagen). At around 50°C myosin (45% to 50% of the myofibrillar proteins) denatures, which results in a substantial increase in cook loss and reduction in water holding capacity. At around 60°C collagen (main connective tissue protein) denatures, which results in a substantial increase in tenderness and increase in cook loss. This is because as the collagen denatures it loses it mechanical strength (increase in tenderness) and can no longer support its own structure, and causes it to contract. This contraction causes fluid within the meat and cook loss caused by the denaturation of myosin to be expelled from the meat by compressive forces (squeezed out). At around 70°C actomyosin (22% of the myofibrillar proteins) denatures. This results in a substantial increase in the cook loss and firming of the meat. The increase in cook loss or decrease in water holding capacity that occurs with myofibrillar protein denaturation is due to the fact that when these proteins denature and aggregate their ability to bind water is greatly reduced. From the results of the cooking regime trials it is recommended that for functional property considerations that during the cooking of further processed meat products (i.e. ready meal applications) a meat temperature of 62°C should be aimed for, for the slowest heating region during cooking (usually the centre). This is because it has been identified that a cooking temperature of 65°C should not be exceeded otherwise detrimental effects can occur to the functional properties of the cooked meat. For health concerns a 7D bacterial death reduction has to be achieved. This means that for a cooking temperature of 62°C the meat has to be held at this temperature for at least 5 minutes. Therefore the total cooking time would be the time needed to heat all the meat to 62°C plus 5 minutes to ensure a safe product. The heating or cooking system employed should also ensure that a minimal amount of the meat is heated above 65°C. This can be easily achieved by minimising the external cooking temperature, but long cooking times will result. An industrial cooking process will be a compromise between the cost associated with longer residence time and product functionality. As mentioned earlier another way to add value is to supply nutritional information for selected cuts. Consequentially one of the objectives of this project was to provide some nutritional information for selected meat cuts. Though the primary objective of this part of the project was to develop a method for producing the needed information, so that Richmond N.Z. Ltd. can develop further information on an as needs basis. The nutritional characteristics of a number of export lamb cuts from the saddle region has also been investigated and a method devised to allow further characterisation of other cuts. The method involves breaking down a standard cut into its constituent components (e.g. Frenched rack consists of loin eye, fat cap, intercostals and fatty tissue). The constituent components are tested for their nutritional properties. The frenched rack nutritional properties are calculated from the nutritional properties of the constituents components and the yield data (percentage of each constituent component within a frenched rack) for frenched racks. This method allowed the identification of the main sources of variation for nutritional characteristics. These differences were found to be caused by the lean to fat ratio, not nutritional differences in lean tissue from the same region of lamb (i.e. loin eye and tenderloin very similar nutritionally). The difference in lean to fat ration also accounts for the variation between grades (i.e. PX grade lamb cuts have a higher fat content than YX grade lamb cuts due to PX grade cuts having a higher percentage fat tissue in their cuts). The cuts characterised were the shortloin section (whole section or chop), rack section (whole section or chop), 75mm racks frenched 25mm, boneless loin and tenderloin for both PX and YX grade lamb. The method will be applicable to other regions of lamb (i.e. hindquarter and forequarter) for which nutritional information already exists, but for which yielding data will have to be collected. The method would also be applicable to other species such as beef and venison, but both nutritional data for constituent components and yielding data would have to be collected.
|
Page generated in 0.0475 seconds