The Quality Changes and Proteomic Analysis of Cattle Muscle Postmortem during Rigor Mortis

Rigor mortis occurs in a relatively early postmortem period and is a complex biochemical process in the conversion of muscle to meat. Understanding the quality changes and biomarkers during rigor mortis can provide a theoretical basis for maintaining and improving meat quality. Herein, a tandem mass tag proteomic method is used to investigate the effects of differentially expressed proteins on the meat quality of cattle Longissimus lumborum muscle postmortem (0, 6, and 24 h). The pH, total sulfhydryl content and sarcomere length decrease significantly during storage. In contrast, meat color values (L*, a*, and b*) and the myofibril fragmentation index increase significantly. Altogether, 147 differentially expressed proteins are identified, most being categorized as metabolic enzymes, mitochondrial proteins, necroptosis and ferroptosis proteins and structural proteins. The results also reveal additional proteins that are potentially involved in rigor mortis, such as cardiac phospholamban, acetyl-coenzyme A acyltransferase, and ankyrin repeat domain 2. The current results provide proteomic insights into the changes in meat quality during rigor mortis.

Fatores do bem-estar animal relacionados ao padrão da carne bovina: uma revisão

O presente estudo tem como objetivo fornecer uma compreensão sobre a relação das condições do bem-estar animal antecedentes ao abate à qualidade da carne baseada em uma revisão bibliográfica. Para isso foi realizado uma busca na literatura utilizando as seguintes palavras-chaves: Welfare, Animal Welfare, Pre-slaughter, Beef, Meat Quality. A partir do início do século XXI foi possível observar um crescente aumento de pesquisas pertencentes ao tema, isso acontece devido ao fato de que cada vez mais o bem-estar animal está relacionado ao estresse do animal, metabolismo durante o rigor mortis – responsável pela conversão do tecido muscular em carne de consumo, assim consequentemente os consumidores finais estão cada vez mais exigentes em relação a isso. No pós-abate de bovinos, podem surgir defeitos da qualidade da carne, denominadas como PSE (pálido, mole, exsudativo) e DFD (escuro, duro, seco), associados a um pH anormal da carne. O bem-estar animal está intimamente ligado desde a criação dos animais até a etapa de pré-abate da carne. A partir do estudo realizado, pode-se definir a necessidade de novas pesquisas que avaliem métodos de prevenção de estresse durante ao pré-abate.

Estresse e seus efeitos na qualidade da carne de peixe: revisão

Na aquicultura, os procedimentos de manejo dos peixes são muitas vezes traumáticos, podendo causar graves reações fisiológicas e bioquímicas. Com o aumento da produção aquícola, percebe-se a necessidade de conhecer a influência do manejo sobre a qualidade da carne. Assim, o objetivo desta revisão bibliográfica foi avaliar como o estresse pode afetar a qualidade da carne em peixes. Através da análise de trabalhos disponíveis, pode-se perceber que o estresse afeta a qualidade da carne do pescado, já que a natação vigorosa leva ao uso intenso do músculo branco. Animais estressados antes do abate entram em rigor mortis mais rapidamente, diminuindo o pH da carne, sua vida útil e qualidade. Além disso, o manuseio e processamento do peixe durante o rigor mortis causam menor rendimento do filé e perda da qualidade da carne. O estresse agudo antes do abate pode desencadear carnes com textura menos firme, ao passo de que estresse de longa duração acarreta em aumento da firmeza da carne. Além disso, o estresse pode provocar aumento na incidência de gaping e diminuição da capacidade de retenção de água. A cor da carne varia muito entre espécies de peixes, podendo ou não estar associada ao estresse ante mortem.

Dying

What actually happens when someone dies? Are there signs that death is approaching? Physicians sometimes notice what is called a terminal drop in basic physiological systems that seems to presage death, but those signs do not occur in every case. In the “twilight of death,” not every cell in the body dies at the same rate. However, once death occurs, the signs are more clear and involve a loss of respiration and heartbeat, rigor mortis, and the pooling of blood, among other things. Some people report near-death experiences, and one might wonder if those provide a glimpse of the afterlife. Yet most of the features of near-death experiences can be explained physiologically. Consciousness and its relationship to the physical brain remain to be understood.

A Comparison of Two Different Slaughter Systems for Lambs. Effects on Carcass Characteristics, Technological Meat Quality and Sensory Attributes

Two slaughter systems for lambs and their effects on meat quality in terms of texture, colour and sensory attributes were compared. The slaughter systems differed in methods for controlling rigor mortis and carcass chilling. One slaughter system (large-scale) used electrical stimulation and fast chilling of carcasses, while the other system (small-scale) did not use electrical stimulation and applied slower chilling, with carcass temperature decreasing over a longer period after slaughter. Ten pairs of ram lamb twins were selected, and one of each pair was slaughtered at the large-scale abattoir and the other at the small-scale abattoir. Carcass weight, conformation, fatness, pH and temperature were recorded. Musculus longissimus thoracis et lumborum was analysed for colour, cooking loss, Warner–Bratzler shear force and sensory attributes. For meat quality attributes, the only differences were found in meat colour L* (lightness; p = 0.0073), sensory attribute “appearance colour” (p = 0.0089) and “fatty flavour” (p = 0.0554). Meat from the small-scale abattoir was darker in colour and had a more fatty flavour than the meat from the large-scale abattoir. For sensory attributes (apart from colour), no significant differences were found between the two abattoir systems.

Pengaruh Cara Kematian dan Tahap Penurunan Mutu Filet Ikan Nila Merah (Oreochromis niloticus)

Perubahan yang dialami ikan setelah mati berlangsung dalam tiga fase, yaitu fase pre rigor, rigor mortis, dan post rigor. Tujuan dari penelitian ini adalah mengetahui pengaruh cara kematian dan waktu preparasi terhadap penurunan kesegaran ikan (pre rigor, rigor mortis, dan post rigor) yang disimpan pada suhu chilling. Pengolahan data dilakukan dengan ANOVA menggunakan rancangan acak kelompok (RAK) yang terdiri dari cara mati (menggelepar, di es, dan ditusuk segera) serta waktu preparasi dimulai (pre rigor, rigor dan post rigor) yang disimpan pada suhu chilling. Hasil penelitian pendahuluan berdasarkan parameter indeks rigor maupun nilai pH dari perlakuan ikan yang ditusuk mengalami penurunan mutu lebih lambat. Hasil penelitian utama laju kemunduran mutu filet ikan nila merah menunjukkan pengaruh nyata antara lama waktu penyimpanan pada setiap parameter uji filet ikan nila merah semua perlakuan. Berdasarkan parameter TVB dan nilai pH filet ikan nila merah mengalami laju penurunan mutu yang lebih lambat pada perlakuan dimatikan ditusuk dalam kondisi pre rigor.

A simple optical pH sensor based on pectin and Ruellia tuberosa L-derived anthocyanin for fish freshness monitoring

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4oC storage. The quantitative pH values were measured based on the UV-Vis spectroscopy absorbance. The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor’s reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness. Overall, this reported optical pH sensor has a novelty as it could be used to monitor the rigor mortis phase of fish meat, which is useful in food industry.

Biochemical and Organoleptic Assessment of Asian Stinging Catfish (Heteropnuestes fossilis) in Two Storage Conditions

The proximate composition, rigor-index, organoleptic quality, and pH of Asian stinging catfish stored at iced condition (SIC) and stored at ambient temperature (SAT) were studied. Rigor mortis for both ice and ambient temperature started immediately after death and the rigor-index was maximum 82.35 % and 63.42% at 4 hrs and 8 hrs storage in SIC and SAT, respectively. Fish SIC showed a remarkably extended maximum rigor-index period of 14 hrs and 2 hrs in fish SIC and SAT, respectively. Fish SIC showed post-rigor period for upto 30 hrs, it was shorter in fish SAT for 18 hrs, though in both storage the rigor-index of the fish did not ceased completely. The moisture, protein, lipid, and ash content of fresh, SIC and SAT fish were 77.30%, 75.57%, and 78.81%, 15.04%, 15.34%, and 14.42%, 6.10%, 6.30%, and 3.47%, 1.99%, 2.67%, and 2.95%, respectively. The initial pH of fresh fish muscle was 6.89 which decreased to 6.32 and 6.12 after 18 hrs in fish SIC and SAT, respectively. The organoleptic quality assessment was in acceptable condition up to 12 days in fish SIC whereas a very short period of 10 hrs at fish SAT. Considering the findings of present study, it is highly recommended to store Asian stinging catfish at iced condition for maintaining shelf-life and quality.

Rigor development and meat quality of Murrah buffalo from different production systems

The purpose of this study was to evaluate the rigor mortis development and its effects on striploins quality of Murrah buffalos from meat (males) and dairy (females) productions. The rigor was monitored during carcass chilling (up to 22 h postmortem) and the meat physicochemical traits was accessed after 72 h postmortem. Glycolytic rate, measured by decreasing pH and glycogen content, was higher (p < 0.05) in female than in male buffalo, leading to a different onset rigor time (5-6 h and 9-10 h, respectively). Male meat had (p < 0.05) lower fat (1.41 vs 3.58%) and insoluble collagen (1.18 vs 1.58 mg g-1) contents, but higher soluble collagen content (5.16 vs 20.38%), sarcomere length (1.65 vs 1.84 µm), myofibrillar fragmentation (334 vs 295) and shear force (39.38 vs 25.92 N) than females. These results suggest that dairy buffalo meat is more tender and can be used on the market as high-quality meat such as from buffalo raised to meat production.