ABSTRACT The study aimed to evaluate the combined use of ultrasound (US) and incorporation of micronized salt (MS) as a strategy for reducing sodium without affecting the quality of beef burgers. Ten treatments were manufactured with varying MS content (0.75 %, 1.0 %, and 1.5 %) and ultrasound time (0, 5, and 10 min), with a control treatment manufactured at 1.5 % of regular salt without ultrasound. The beef burgers formulated with 0.75 % MS submitted to the US for 10 min (M0.75US10) reduced the salt content by 50 %, thereby efficiently maintaining texture profile (hardness, springiness, cohesiveness, and chewiness) and decreasing the cooking loss and diameter reduction compared to the control treatment. M0.75US10 treatment also preserved the color of samples after cooking, keeping myoglobin stable. Therefore, micronized salt coupled with ultrasound technology reduces sodium chloride content in beef burgers, enabling the application of clean technology to reduce sodium content in meat products efficiently. (US (MS 075 0 75 (0.7 1 1. 15 5 0, (0 min, , min) 0.7 M075US10 MUS M0 75US10 M (M0.75US10 hardness, hardness (hardness springiness cohesiveness chewiness M0.75US1 stable Therefore 07 7 (0. ( 0. M075US1 75US1 (M0.75US1 M0.75US M075US 75US (M0.75US

ABSTRACT In the last decade, other quality attributes have emerged as the main aspects that impact pork consumers acceptance, such as environmentally friendly production, nutritional value, and animal welfare. This study applies a Check-All-That-Apply (CATA) questionnaire for sensory characterization of loins from genetically lean immunocastrated male pigs fed diets containing either a standard commercial diet with 1.5 % soybean oil (control) or 3 % oil from either soybean oil (SO), canola oil (CO), or fish oil (FO) during the growing-finishing phases. Twenty CATA attributes for loin samples were generated. We interviewed 101 consumers to select all the CATA terms that they considered suitable to characterize sensory attributes of longissimus lumborum muscle samples of pigs from each dietary treatment. The CATA results indicated differences among pork loin samples depending on the source and inclusion level of dietary oil. Loins from pigs fed 3 % SO were characterized by a higher frequency of the “juicy texture” attribute (p < 0.05) and a lower frequency of the “dry texture” attribute (p < 0.05) compared to loins from 3 % FO-fed pigs. Moreover, loins from pigs fed 3 % SO had a lower citation frequency of the “tasteless” attribute (p < 0.05) compared to loins from 3 % FO-fed pigs. The attributes “cooked pork meat-like taste”, “juicy texture”, “tender texture”, and “brightness” were placed close to the overall liking. “Tender texture”, “juicy texture”, “pork meat-like” (odor and taste), and “cooked pork meat-like taste” attributes were considered drivers of liking. Feeding genetically lean immunocastrated male pigs with diets containing 3 % SO may be advisable from a pork sensory quality perspective.

ABSTRACT Myoglobin (Mb) is a sarcoplasmic heme protein present in muscle cells, which acts as a short–term oxygen (O2) reserve in the muscle tissue. After slaughtering and exsanguination, Mb is the major pigment that provides the red color in meat. The concentration of Mb together with its redox state are two pivotal factors that determine meat color. The elevated pH of dark–cutting beef can affect both physical and biochemical properties resulting in decreased oxygenation. The darkening observed in high ultimate pH (pHu) beef concerns meat processors as color is the initial attribute that impacts on the purchase. Thus, any atypical meat color (i.e., loss of brightness) reduces consumer interest in the product. Several studies have demonstrated that immunological castration is effective in preventing both aggressive behavior and undesirable dark–cutting of bull meat. However, little information is available on the effects of processing techniques that limit the oxidation of ferrous iron (Fe2+), Mb or promote metmyoglobin (MMb) reduction in dark–cutting beef. Because of the importance of color to fresh beef marketability, this review aimed at overviewing the significance of pHu in beef color and color stability and to discuss new alternatives for improving and assessing the beef color of dark–cutting beef, especially in Nellore bulls and their crossbreds, which are widely used in beef cattle production in Brazil.

ABSTRACT: Bos taurus indicus temperament is variable and affects beef tenderization. Our objective was to investigate temperament and performance of non–castrated Nellore and identify groups based on Longissimus lumborum (LL) pH decline as well as beef characteristics produced by those groups. We investigated 94 animals with a subset of carcasses (n = 24) selected based on LL pH at 24 h postmortem (pm) to represent two groups: resistant to pH decline (> 5.8 called pH–Res; n = 10) and normal (< 5.7 called pH–Nor; n = 14). Steaks were fabricated from the LL muscle and randomly assigned to aging (2, 7, 14, and 21 days). Sarcomere length, cooking loss, myofibrillar fragmentation index (MFI), and Warner–Bratzler shear force (WBSF) were determined. Data on temperament were investigated in a multivariate approach, while beef data were compared between groups using the analysis of variance. Rectal temperature at the beginning of the finishing phase and total weight gain were greater and related to animals in the pH–Res group (p < 0.01 and p = 0.03, respectively). Temperature and pH decline curves, sarcomere length, and cooking loss revealed that pH–Res produced beef with lower quality compared to the pH–Nor group. Results for MFI and WBSF did not show differences between groups within each time pm; however, overall steaks from pH–Res were tougher (p = 0.06). Incidence of LL pH between 5.8 and 5.9 at 24 h pm did not compromise the tenderization rate or extension; however, it affected the water holding capacity in this population of Nellore cattle.

Meat has played a crucial role in human evolution and is an important component of a healthy and well-balanced diet on account of its nutritional properties, its high biological value as a source of protein, and the vitamins and minerals it supplies. We studied the effects of animal fat reduction and substitution by hydrogenated vegetal fat, sodium alginate and guar gum. Fatty acid composition, lipid oxidation, color and instrumental texture as well as the sensorial difference between low, substituted-fat and the traditional formulations for mortadella-type products were analyzed. Both substitution and reduction of animal fat decreased the saturated fatty acids percentage from 40% down to 31%. A texture profile analysis showed differences between the formulations. Furthermore, lipid oxidation values were not significant for treatments as regards the type and quantity of fat used while the use of sodium alginate and guar gum reduced the amounts of liquid released after cooking. Animal fat substitution does cause, however, a difference in overall sensorial perception compared with non-substituted products. The results confirm the viability of substituting vegetal fat for animal fat.

Okara é o subproduto gerado na fabricação de leite de soja ou tofu. Okara úmido foi adicionado em hambúrguer de carne bovina nas concentrações de 0%, 20% e 25%. A influência da adição de okara em 0%, 20% e 25% sobre certas propriedades físico-químicas, de textura e sensoriais em hambúrgueres bovinos com reduzido teor de gordura foi investigada. Os hambúrgueres formulados com okara (104,0-106,0 kcal/100 g) apresentaram 60% menos calorias do que hambúrgueres comerciais de carne bovina (268,8 kcal/100 g). A análise do perfil de textura mostrou que o aumento da concentração de okara foi acompanhado por um aumento de dureza (p < 0,05), com concomitante diminuição dos valores de mastigabilidade, elasticidade e coesividade. Notas sensoriais significativamente mais baixas (p < 0,05) para sabor foram observadas nos hambúrgueres contendo 25% de okara úmido. No entanto, os resultados da análise sensorial mostraram que a suculência, aparência, maciez e aceitabilidade geral dos hambúgueres formulados com okara não diferiram estatisticamente do controle (0% okara). Okara úmido a 20% pode ser utilizado como fonte de proteína não cárnea para a produção de hambúrguer bovino com gordura reduzida sem alterar a sua qualidade sensorial.

Okara is a by-product generated during the manufacture of soymilk and tofu. Wet okara was added to beef burgers at 0%, 20%, and 25%. The effects of okara on certain physicochemical, textural, and sensory properties of reduced fat beef burgers were investigated. The beef burgers formulated with okara (104.0-106.0 kcal/100 g) had 60% less calories than commercial beef burgers (268.8 kcal/100 g). The texture profile analysis showed that the addition of wet okara led to a significant increase in hardness (p < 0.05) and a concomitant reduction in the values of chewiness, springiness, and cohesiveness. Lower sensory scores (p < 0.05) of flavour were observed in the beef burgers containing 25% wet okara. However, the sensory evaluation results showed that juiciness, appearance, tenderness, and overall acceptability of beef burgers formulated with okara did not differ statistically from that of the control (0% okara). Wet okara (20%) can be used as a non-meat protein source in the production of reduced-fat beef burgers without changing their sensory quality.

O objetivo deste trabalho foi avaliar a aceitabilidade e a segurança microbiológica de linguiça de frango frescal não curada formulada com baixo teor de gordura, considerando as evidências científicas que correlacionam câncer e doenças cardiovasculares à dieta. Duas formulações de linguiça frescal de frango foram processadas, usando diferentes concentrações de carmim cochonilha, extrato de alecrim e antioxidantes sintéticos utilizados para dar cor, aparência e sabor agradáveis aos produtos. Então, a cor instrumental (L*, a*, b*, C* e h*), contaminação microbiana e testes sensoriais (ordenação-preferência e aceitação) foram utilizados para avaliar a qualidade das linguiças de frango não curadas. A cor instrumental (chroma e hue), as propriedades sensoriais das linguiças não curadas A e B foram similares ao da linguiça comercial curada (C). Porém, a cor sensorial e a aparência das amostras A e B foram estatisticamente superiores às das linguiças comerciais não curadas D, elaboradas sem a adição de nitrito ou pigmentos. Os resultados mostraram que é possível produzir linguiça de frango frescal não curada contendo reduzido teor de gordura com segurança e alta qualidade, utilizando pigmentos e antioxidantes naturais.

The purpose of this study was to evaluate the acceptability and the microbiological safety of uncured fresh chicken sausages with reduced fat content, considering the scientific evidence that correlated cancer and cardiovascular diseases to this diet. Two formulations of uncured fresh chicken sausage were processed using different concentrations of cochineal carmine pigment, rosemary extracts and synthetic antioxidants, which are used to give color, appearance and pleasant flavor to the products. Then, instrumental color (L*, a*, b*, C* and h*), microbial contamination and sensory tests (ranking and acceptance) were used to evaluate the quality of the uncured chicken sausages. The instrumental color (chroma and hue) and the sensory properties of the A and B uncured sausages were similar to the commercial cured sausage (C). However, the sensory color and appearance of samples A and B were statistically higher than those of the commercial uncured sausages D, which are prepared without the addition of nitrite or pigments. The results showed that it is possible to produce safe and high-quality uncured fresh chicken sausage with reduced fat content, using natural pigments and antioxidants.

Foi utilizada a porção comestível da paleta de cordeiros Santa Inês de 12 castrados e 12 não castrados, abatidos em diferentes idades (84, 168, 210, 252 dias). Obteve-se o peso da meia carcaça e as paletas foram pesadas e armazenadas a - 5 ºC. A porção comestível (músculo e gordura) foi analisada quimicamente para determinação da quantidade de lipídios totais, teores de colesterol e perfil de ácidos graxos. Cordeiros castrados e não castrados aumentaram o peso corporal (p = 0,0393; p = 0,0017) e peso da meia carcaça (p = 0,0240; p = 0,0017), respectivamente. O peso da paleta foi incrementado nas carcaças dos ovinos não castrados (p = 0,0110). A porção comestível da paleta dos animais castrados apresentou maior quantidade de lipídios totais (16,09 g.100 g-1). O teor de colesterol foi influenciado pela castração (p = 0,0001), reduzindo com a idade. Cordeiros castrados apresentaram maior quantidade de C18:1 T11, CLA e C18:0. A castração influencia o conteúdo de colesterol da paleta; entretanto, tanto cordeiros castrados quanto não castrados tiveram o conteúdo de colesterol reduzido com o aumento da idade. A castração e a idade interferiram na concentração de ácido esteárico da porção comestível da paleta de cordeiros.

The edible portion of the shoulder of 12 castrated and 12 non-castrated Santa Inês lambs slaughtered at different ages (84, 168, 210, 252 days) were used. The shoulders were chemically analyzed to determine the quantity of total lipids, cholesterol, and fatty acids composition. Castrated and non-castrated lambs gained body weight (p = 0.0393, p = 0.0017) and half carcass weight (p = 0.0240, p = 0.0017), respectively. The shoulder weight was increased in the carcasses of non-castrated lambs (p = 0.0110). The edible portion of the shoulder of castrated lambs presented higher total lipids (16.09 g.100 g-1). The cholesterol content was influenced by castration (p = 0.0001) reducing with age. Castrated animals presented higher content of C18:1 T11, CLA, and C18:0. The shoulder weight is only increased with increasing age in the carcasses of non-castrated lambs. Castration influences the cholesterol content of the shoulder; however, both castrated and non-castrated lambs had their cholesterol contents reduced with increasing age. Castration and age interfered in the estearic acid concentration of the edible portion of lamb shoulder.

Gas production from microbial deterioration in vacuum-packs of chilled meat leads to pack distension, which is commonly referred as blown pack. This phenomenon is attributed to some psychrophilic and psychrotrophic Clostridium species, as well as Enterobacteria. The ability of these microorganisms to grow at refrigeration temperatures makes the control by the meat industry a challenge. This type of deterioration has been reported in many countries including some plants in the Midwestern and Southeastern regions of Brazil. In addition to causing economic losses, spoilage negatively impacts the commercial product brand, thereby impairing the meat industry. In the case of strict anaerobes species they are difficult to grow and isolate using culture methods in conventional microbiology laboratories. Furthermore, conventional culture methods are sometimes not capable of distinguishing species or genera. DNA-based molecular methods are alternative strategies for detecting viable and non-cultivable microorganisms and strict anaerobic microorganisms that are difficult to cultivate. Here, we review the microorganisms and mechanisms involved in the deterioration of vacuum-packaged chilled meat and address the use of molecular methods for detecting specific strict anaerobic microorganisms and microbial communities in meat samples.

A cadeia da carne de frango no Brasil é um importante setor do agronegócio, ocupando a terceira maior produção mundial e o primeiro lugar nas exportações. Para atender a demanda, é fundamental minimizar os problemas de manejo, que causam o aparecimento de problemas fisiológicos. A seleção genética intensiva, que é usada na obtenção de taxas de crescimento mais rápidas para frangos de corte, contribuiu para que as linhagens melhoradas atuais sejam muito susceptíveis ao estresse térmico. Quando a temperatura ambiente se eleva acima da zona de termoneutralidade, a ave é submetida a uma condição de estresse, podendo gerar hipertermia aguda, alcalose respiratória, desequilíbrio eletrolítico, redução no consumo de alimento, menor taxa de crescimento, aumento na mortalidade e/ou até mesmo efeitos negativos na qualidade da carne, pela incidência de carnes pálidas e, em outros casos, escuras, interferindo nas propriedades como rendimento industrial, capacidade de retenção de água, cor e maciez. Os resultados de avaliação dos parâmentros de qualidade observados na literatura evidenciam que o estresse térmico, crônico ou agudo sofrido por frangos de corte geram consequências negativas sobre as propriedades funcionais da carne. São necessários mais estudos sobre essa questão, principalmente em relação ao Brasil, por ser um país tropical, com elevadas temperaturas, especialmente, no verão, para compreender, prevenir e contornar a extensão ou intensidade do estresse, evitando problemas e prejuízos para a cadeia da carne.

The chicken meat chain in Brazil is an important sector of agribusiness, accounting for the third largest world's production and first place in exports. To meet this demand, it is essential to minimize management problems, which cause the appearance of physiological problems. The intensive genetic selection used to obtain faster growth rates for broilers contributed for the current improved strains to become very susceptible to heat stress. When the environment temperature rises above the thermoneutrality zone, the bird is submitted to a stress condition, which can generate acute hyperthermia, respiratory alkalosis, electrolyte imbalance, reduction in food consumption, lower growth rate, increased mortality rate and even negative effects on meat quality due to the incidence of pale meat and dark in other cases, interfering in properties such as industrial yield, water holding capacity, color and tenderness. The results of the evaluation of quality parameters observed in literature showed that the heat stress, chronic or acute, suffered by broiler chickens, generates negative consequences on the functional properties of meat. Further studies with this research line should be conducted, mainly in Brazil, for being a tropical country with high temperatures in the summer in order to understand, prevent and overcome the extent or intensity of this stress, avoiding problems and damages to the meat chain.

Objetivou-se avaliar os efeitos do fornecimento de polpa cítrica na dieta sobre as características de carcaça e a qualidade da carne de cordeiros em confinamento. Utilizaram-se 32 cordeiros Santa Inês distribuídos em delineamento de blocos completos casualizados com quatro tratamentos e oito repetições, os quais foram definidos pelo peso e pela idade dos animais no início do experimento de desempenho. Os animais foram alimentados com rações contendo 90% de concentrado (milho moído e/ou polpa cítrica, farelo de soja e minerais) e 10% de feno de coastcross (Cynodon spp). A polpa cítrica foi adicionada nos níveis 23,7; 46,1 e 68,4% da MS em substituição a 33, 67 e 100% do milho. Ao atingirem 33 kg de peso corporal médio, os cordeiros foram abatidos para avaliação dos rendimentos de carcaça quente e fria, da perda por resfriamento, da espessura de gordura de cobertura, da área de olho-de-lombo, dos rendimentos de cortes e da proporção músculo:gordura:osso, além da capacidade de retenção de água, da cor, da perda de peso por cozimento e do pH da carne. As características de carcaça não foram alteradas pela substituição parcial ou total do milho por polpa cítrica. Entretanto, a substituição total do milho por polpa cítrica reduziu em 12,4% o teor de gordura na carcaça.

The objective of this trial was to determine the effects of feeding diets containing citrus pulp on carcass characteristics and meat quality of feedlot lambs. Thirty-two Santa Ines lambs were distributed in a complete randomized block design according to body weight and age at the beginning of the performance trial. Lambs were fed diets containing 90% concentrate (corn and/or citrus pulp, soybean meal and minerals) and 10% coastcross hay (Cynodon spp). Citrus pulp was added at levels 23.7, 46.1 and 68.4% in the DM, replacing corn by 33, 67 or 100%. When lambs reached 33 kg of BW, they were slaughtered to determine dressing percentage, cold carcass yield, chilling loss, backfat thickness, loin eye area, cut yields and proportion of muscle, fat and bone. In addition, water holding capacity, color, cooking loss and pH were determined. Carcass characteristics were not altered by feeding citrus pulp to the lambs. However, the total replacement of corn by citrus pulp decreased carcass fat content by 12.4%.

O objetivo desta pesquisa foi avaliar o efeito de diferentes períodos de jejum alimentar (três, seis, nove, 12, 15 e 18 horas) na perda de peso da ave viva, rendimento da carcaça quente e fria (antes e após o resfriamento no "chiller"). Os atributos de qualidade da carne de peito de frango criados no sistema convencional tais como cor, capacidade de retenção de água (CRA), pH, força de cisalhamento e perda por cozimento foram avaliados. Neste experimento foram utilizados frangos de corte da linhagem Ross com 46 dias de idade. Os resultados mostraram que períodos prolongados de jejum alimentar teve efeito estatístico (P<0,05) na perda de peso das aves vivas. Essa perda foi de 2,27% para três horas a 7,51% para 18 horas de jejum alimentar. A queda no rendimento da carcaça a quente começou às nove horas de jejum (P<0,05) com rendimento de 67,4% após três horas a 66,2 % após nove horas de jejum alimentar. O rendimento da carcaça resfriada diminuiu de 74,8% após três horas a 73,2% após seis horas de jejum (P<0,05). Os maiores rendimentos de carcaça foram obtidos com os frangos de corte submetidos aos períodos entre 3 e 6 horas de jejum (carcaça quente) e três horas (carcaça resfriada). Não foram observadas diferenças estatísticas (P>0,05) para o valor de L*, a* e b*, CRA, pH e perda por cozimento da carne de peito devido aos diferentes períodos de jejum alimentar. Os valores da correlação de Pearson mostraram uma correlação negativa (P<0,001) tanto entre o pH e o valor de L* quanto entre o valor de L* e a CRA nos diferentes períodos de jejum.

This research was aimed at evaluating the effect of different feed withdrawal (FW) periods (3, 6, 9, 12, 15 and 18 hours) on the live bird weight loss, dressed and chilled carcass yield (before and after of water chilling). The attributes of chilled breast meat quality of broilers raised in the conventional system were also evaluated, such as color, water holding capacity (WHC), pH, shear force and cooking loss. In this experiment, 46-day-old Ross broilers were used. The results of this study indicated that prolonged FW periods have a significant effect (P<0.05) on live broiler weight losses, from 2.27% for 3 hours FW to 7.51% for 18 hours FW. The reduction in dressed carcass yields became statistically significant after 9 hours of FW, ranging from carcass yield of 67.4% after 3hours to 66.2% after 9 hours FW. Chilled carcass yields dropped from 74.8% after 3 hours to 73.2% after 6 hours FW (P<0.05). The highest carcass yields were observed for broilers submitted to FW periods between 3 and 6 hours (dressed carcass yield) and 3 hours (chilled carcass yield). No statistical differences (P>0.05) were observed for L*, a* and b values, WHC, pH, cooking losses and pH of the breast meat submitted to different FW periods. Pearson correlation values showed a negative (P<0.001) correlation between pH and L* value, and between L* value and WHC, which varied with FW periods.

Com o objetivo de acompanhar a estabilidade físico-química e microbiológica da carne mecanicamente separada (CMS) de diferentes origens e estocada durante 99 dias a -18 °C, foi realizada prévia mistura de conservante (nitrito de sódio) e antioxidante (eritorbato de sódio) em CMS obtida de duas linhagens de aves: galinhas matrizes de corte e galinhas poedeiras comerciais brancas. Na CMS de cada linhagem foram realizados três diferentes tratamentos: 1) controle (sem aditivos); 2) adição de 150 ppm de nitrito; e 3) adição de 150 ppm de nitrito e 500 ppm de eritorbato. Os resultados encontrados demonstraram que a adição de nitrito isoladamente não impediu a oxidação lipídica, avaliada através do índice de TBARS, nem a alteração na cor, avaliada em colorímetro. Por outro lado, a adição de nitrito juntamente com eritorbato foi efetiva na redução dos problemas de oxidação lipídica na CMS de galinhas matrizes, e em menor grau, na CMS de poedeiras. A adição de nitrito e eritorbato na CMS também melhorou a preservação da cor vermelha desejável (a*) ao longo do tempo. A avaliação da estabilidade microbiológica da CMS, realizada no primeiro e último dia de estocagem congelada, para microrganismos mesófilos, Escherichia coli, Staphylococcus aureus, Clostridium perfringens e Pseudomonas spp., e quinzenalmente para microrganismos psicrotróficos, indicou que não houve uma variação significativa nas contagens em função do tratamento utilizado (diferentes aditivos adicionados). Não foi detectada Salmonella spp. em nenhuma das amostras analisadas. Em função da melhoria da estabilidade oxidativa, recomenda-se a adição de nitrito (150 ppm) e eritorbato (500 ppm) em CMS de galinhas matrizes a ser estocada congelada por um período prolongado.

With the objective of following the microbiological e physical-chemical stability of mechanically separated meat (MSM) of different origins and stored during 99 days at -18 °C, a previous mixture of preservative (sodium nitrite) and antioxidant (sodium erythorbate) in MSM obtained from two poultry breeds: broiler breeders and white layers, was made. In the MSM of each breed, three different treatments were carried out: 1) control (without additives), 2) addition of 150 ppm nitrite and 3) addition of 150 ppm nitrite and 500 ppm erythorbate. The results obtained demonstrated that nitrite added separately did not hinder lipid oxidation, evaluated through the TBARS index, or the color changes, evaluated with a colorimeter. On the other hand, the addition of nitrite together with erythorbate was effective in reducing the problems of lipid oxidation during prolonged frozen storage. The evaluation of the microbiological stability of the MSM, carried out in the first and last day for mesophilic microorganisms, Escherichia coli, Staphylococcus aureus, Clostridium perfringens and Pseudomonas spp., and every 15 days for psycrotrophic microorganisms, did not indicate a significant variation in the counts, as a function of the treatment applied. Salmonella spp. was not detected in the samples analyzed. Considering the improvement in the oxidative stability, the addition of nitrite (150 ppm) and erythorbate (500 ppm) in MSM broiler breeders to be frozen stored for a long time can be recommended.

O estresse térmico agudo (ET) causa alterações na estrutura das miofibrilas, afetando propriedades funcionais da carne, principalmente a capacidade de retenção de água. Identificaram-se mudanças na proteólise e migração entre as frações miofibrilar e sarcoplasmática, decorrentes do ET pré-abate, através do índice de fragmentação miofibrilar (MFI), SDS-PAGE para troponina (SDS), imunodetecção de vinculina (IV) e força de cisalhamento (FC). Seiscentos frangos (Gallus gallus) foram abatidos em três dias diferentes (DA). Em cada DA os animais foram colocados em caixas de transporte (10 aves/caixa) e submetidos a ET (35ºC, 75 - 85% UR)por 2 horas. Simultaneamente, o outro grupo de animais (NET) foi mantido em caixas em condição termoneutra (22ºC, 83 ± 6,6% UR) pelo mesmo período de tempo. Após o abate o músculo do peito foi coletado e mantido refrigerado, até a retirada de todas as amostras (0, 1, 2, 6 e 24 horas pós-abate). O valor de luminosidade (L* < 49, normal e > 51, alto), foi o parâmetro utilizado na amostragem para SDS e IV. A cinética do MFI demonstrou que a taxa de fragmentação foi superior nos animais NET, indicando que o estresse térmico pode prejudicar o processo de proteólise. Entretanto, a extensão da fragmentação não variou, bem como os valores de FC. No SDS ocorreram padrões diferenciados de fragmentação entre aves ET e NET. Modificações na fração sarcoplasmática foram observadas em amostras com L*, independentemente da condição ambiental.

Acute heat stress (AHS) modifies the structure of myofibrils affecting functional properties of meat, mainly the water holding capacity. This experiment aimed to identify changes in proteolysis and migration between the myofibrillar and sarcoplasmatic fractions due to pre-slaughter AHS. Myofibrillar fragmentation index (MFI), SDS-PAGE, western blot of vinculin (WB) and shear force (SF) were determined. Six hundred broilers (Gallus gallus) were slaughtered in three different days (ST). In each ST, groups of ten animals were placed in transport crates and submitted to AHS (35ºC, 75 - 85% RH) for 2 hours. Simultaneously, the non-stressed broilers (NS) were kept in thermoneutral environment (22ºC, 83 ± 6.6% RH) within the crates in the same density. After slaughter, the breast muscles were kept refrigerated until the withdrawal of all samples (0, 1, 2, 6 and 24 hours after slaughter). Sampling within AHS and NS birds was collected according to lightness value (normal L* < 49, and high > 51), except for determination of MFI and SF. The lightness was used later to perform SDS-PAGE and WB analyses. MFI kinetics showed that the fragmentation rate was superior in animals NS, indicating that AHS can harm proteolysis and rate of myofibrillar fragmentation. However, the extent of fragmentation did not change, as well as SF values. SDS-PAGE for Troponin fragments indicated a differentiated pattern between AHS and NS. The WB did not show alterations in vinculin fragmentation. Modifications in sarcoplasmatic fraction are observed in meat with high L*values, independent of environmental condition.

O presente experimento foi realizado para determinar a efetividade do tratamento térmico em água e vapor a 80 °C tendo como objetivo a inativação do Clostridium botulinum tipo E, utilizando-se amostras de Semintendinosus. Foram realizadas ainda a avaliação da maciez objetiva, utilizando-se a análise de força de cisalhamento, e a avaliação sensorial dos atributos de suculência, maciez subjetiva, "flavor" e presença de colágeno. O tratamento a 80 °C foi efetivo na eliminação do microrganismo, contudo não houve diferença significativa no atributo maciez objetiva (força de cisalhamento) avaliado nos dois tratamentos utilizados. A avaliação sensorial apresentou correlação positiva entre os atributos maciez e suculência, enquanto o colágeno apresentou correlação negativa com a maciez. O "flavor" não apresentou correlação com os atributos maciez, suculência e presença de colágeno.

The purpose of the experiment reported here was to determine the effectiveness of heat treatments in water and in steam at 80 °C to inactivate the bacterium Clostridium botulinum type E in samples of beef Semitendinosus muscle. The product’s tenderness was evaluated based on a Warner-Bratzler Shear Force (WBSF) analysis and its attributes of juiciness, subjective tenderness, flavor and connective tissue were evaluated sensorially. The treatment at 80 °C effectively killed the bacterium, but no significant difference was found in the attribute of objective tenderness (shear force) evaluated after the two treatments. The sensorial analysis indicated a positive correlation between the attributes of juiciness and tenderness, while the connective tissue showed a negative correlation to tenderness. Flavor proved uncorrelated with tenderness, juiciness and connective tissue.