Postmortem changes in muscle electrical properties of. Effect of different ultimate ph range on meat quality of. As post mortem glycolysis proceeds, the muscle becomes inextensible. Minimization of postmortem glycolysis by epinephrine administration more than 5 hr before slaughtering increased the ultimate ph of meat and the tenderness. Technology of meat, poultry, fish and seafood products module. The probable reason can be attributed to the fact that metabolic reactions continues after somatic death of an individual and glycolysis affects the postmortem blood glucose level in peripherally collected blood. Post mortem alterations to the muscle proteome reflect the biological complexity of the process of muscle to meat conversion, a process that, despite decades of advancements, is all but fully understood. The objective of the current study was to investigate the effects of supplementing. Meat and meat products encyclopedia of life support systems. Glycolysis and the associated ph decline are of primary importance for meat. All relevant data are within the paper and its supporting information files. Request pdf characteristics of meat quality and the acceleration of postmortem glycolysis by electrical stimulation summarya brief period of electrical stimulation of freshly slaughtered lamb.
Consumption of oxidized oil increases oxidative stress in. Request pdf characteristics of meat quality and the acceleration of post mortem glycolysis by electrical stimulation summarya brief period of electrical. The post mortem proteolysis is responsible for most of tenderization that occurs later during aging koohmaraie, 1996. Glycolysis is one of the key metabolic pathways in the conversion of muscle to meat. Over 10 million scientific documents at your fingertips. The purpose of meat inspection is to certify whether or not meat is fit for human consumption. Atp consumed by noncontractile activity of amatpase and ion pumps. Presented at the 55th international congress of meat science and technology. Understanding and utilizing postmortem events and processes eric pouliot1 with the collaboration of c. Sep 01, 2007 two experiments were conducted to investigate the influence of age of mature cows 24 yr, 68 yr, and 1012 yr cows. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
The effects of ante mortem stressors such as stunning, struggling, environmental temperature and feed withdrawal on the biochemical changes of broiler breast muscle are assessed in relation to postmortem biochemical changes and the subsequent tenderness of broiler breast meat. Very rapid glycolysis due to excitement antemortem or due to holding on kill floor a long time before chilling postmortem. Dietary energy source can influence muscle glycogen storage at slaughter. Postslaughter changes in atp metabolites, reducing and.
While atp, adp and amp were rapidly broken down, the concentration of imp rose rapidly and remained high. However, few studies have demonstrated whether the dietinduced change of muscle glycogen is achieved by the transformation of muscle fibre type. Histochemical and meat quality characteristics of longissimus dorsi ld and psoas major pm muscles were made. Postmortem changes in atp, glucose6phosphate and ph demonstrated that the rate of postmortem glycolysis in the pm was significantly faster than in the ld. Effect of sex, age, and length of preslaughter conditioning. The conversion of muscle to meat actually starts when someone decides to sell and market their pigs because this is when ante mortem stress occurs with the marketing and handling of animals. In humans, rigor mortis can occur as soon as four hours after death. Effect of cold stress during transportation on postmortem. Researchers have also used muscle glycolytic potential or glycogen. Request pdf characteristics of meat quality and the acceleration of postmortem glycolysis by electrical stimulation summarya brief period of electrical. Consequently, muscle glycogen is metabolized via anaerobic glycolysis, which is less efficient at generating atp. Postmortem inspection food safety and inspection service. Sheep, rabbit and oxmuscle minces prepared soon after slaughter were diluted with 1 vol.
Effect of some antemortem stressors on perimortem and. Postmortem biochemistry of meat and fish journal of. The postmortem changes that take place when muscle is converted into meat have a marked effect on the quality of the meat. Temperature and the rate and extent of ph fall have a considerable effect on meat quality attributes in different animal species scheffler et al. Generally the carcasses are stored for a few days after slaughter. The explanation to this hitherto incongruent outcome can be attributed, in part, to the contribution of proteolysis. Pdf regulation of postmortem glycolysis in ruminant muscle. Contribution of postmortem muscle biochemistry to the. Conditions behind the pse poultry meat are believed to be the same as observed in pork. This is caused by preslaughter stress and, as the term suggests, results in a darker meat with undesirable meat quality characteristics.
No true crossover at f1,6p 2, hence regulation is not at pfk. The effect of nutrition on muscle ph decline and ultimate. Effects of early postmortem muscle ph and temperature on meat tenderness 6. Other studies have also demonstrated the importance of temperature for the process of glycolysis, which affects meat quality. No detectable breakdown products of thick and thin filaments. The aim of this study was evaluation of the postmortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic acid, as well as examination of their impact on technological and sensory quality of selected muscles from. The extent of post mortem glycolysis also has an effect on the tenderness of beef, pork, and lamb. Changes in specific myofibrillar proteins during the aging process a. Stimulated carcasses put into a blast freezer at 5 hr post. The postmortem proteolysis is responsible for most of tenderization that occurs later during aging koohmaraie, 1996.
Post mortem procedures 11 if a cement floor is available which is rarely the case, this greatly facilitates subsequent disinfection. There are no clearly written guidelines covering all situations. Bruce marsh for a number of reasons, the ph and temperature changes taking place in early postmortem muscle are of interest and importance to the meat investigator. Although the same ryanodine mutation found in pork was not. May increase rate of glycogenolysis and thereby increase glycolysis. Smith this study was conducted to assess the regulation of glycolysis by 6phosphofructokinase pfk during the postmortem metabolism of beef muscle. Influence of postmortem muscle glycogen content on the. Regulation of postmortem glycolysis in ruminant muscle d. This includes muscle contraction and it also helps initiate relaxation. Regulation of postmortem glycolysis in ruminant muscle 2014 ferguson, d. The importance and value of meat tenderness tenderness has been repeatedly reported as the most important quality attribute of meat hu.
This paper details the postmortem changes that take place in the muscular tissue of poultry and the consequences of these on the resulting meat quality at the point of consumption. If possible, a site for the post mortem remote from contact with other wild animals and domestic livestock should be selected. The inclusion of glycogen, atp, adp, nad or magnesium chloride in the diluent had little effect on the ultimate ph of the diluted mince. Postmortem changes in muscle electrical properties of bovine. Postmortem glycolysis is one of the most important factors determining the quality of meat. Both pse and dfd meat induce significant losses to the meat.
Effects of earlypostmortem muscle ph and temperature on. Regulation of postmortem glycolysis and meat quality. Because of protein denaturation, there is exudation of moisture and discoloration. Also, few studies if any have reported on whether these oxidation conditions in the diet can regulate meat quality including post mortem ph changes and waterholding capacity in broiler breast meat. Pse meat immediately after slaughter due to accelerated glycolysis 23. Effects of dietary energy sources on post mortem glycolysis, meat quality and muscle.
Increases tenderness of meat unless the meat already is tender. Effect of prerigor freezing and thawing on the intermediary metabolism. Postmortem changes that occur in the conversion of muscle to meat not only alter some of its biochemical and physical properties but also play an important role in improving its acceptability as food pearson, 1987. These results suggest that producing meat at a higher phu will result in acceptable quality by reducing the risk for pse and high drip losses.
Start a free trial of quizlet plus by thanksgiving lock in 50% off all year try it free. Causes and contributing factors to dark cutting meat. It is also important to note that anaerobic glycolysis is significantly less efficient. Effect of cold stress during transportation on post mortem metabolism and chicken meat quality a thesis submitted to the college of graduate studies and research in partial fulfillment of the requirements for the degree of doctor of philosophy in the department of food and bioproduct sciences university of saskatchewan. No visible degradation of thick and thin filaments. In one reaction in the phosphagen system, the enzyme adenylate kinase catalyzes the. Microorganisms may enter the meat by penetration from the surface, which is a slow process, and by following the cavities in meat, that is, the blood and lymph vessels. There is substantial evidence to show that consumers rate. Pork with normal color and whc reaches an ultimate ph of 5. In both cases, abnormal physicochemicalproperties of meat color, waterholdingcapacity are.
The relationship between the degree of acceleration of post. Effect of postmortem changes on meat quality wismer. Postmortem glycolysis in bovine longissimus muscle a. Pse pork shortterm glycogen depletion prior to death. The post mortem pm glycolysis rate is influenced by many factors during the transformation of muscle to meat. Effect of glycogen concentration and form on the response to electrical stimulation and rate of postmortem glycolysis in ovine muscle. In this way the postmortem changes are nearly inhibited. Steaks from more mature cows had an increased p meat using ante mortem enzyme injection and post mortem water injection 19610502. Presumably, postmortem glycolysis and muscle ph decline is stopped, under normal carcass. A pit may have to be dug to dispose of the carcass, so. Brazilian archives of biology and technology scielo. During oxygen debt, such as that occurring immediately following the death of animals, anaerobic metabolism is initiated in an attempt to restore homeostasis within the muscle.
Low salt pigmeat products and novel formulations slu. Effects of postmortem glycolysis on the quality of hotdeboned bovine muscle. This study investigated the effect of early postmortem temperature on broiler protein characteristics and meat quality. Post mortem changes and conversion of muscle into meat death of the animal and consequences of circulatory failure. While most of atp produced postmortem arises from glycolysis, muscle has a separate mechanism known as the phosphagen system to generate atp. Commonwealth scientific and industrial research organisation division of food preservation, meat research laboratory, cannon hill, queensl. These glycolytic and auto lytic changes are discussed in relation to the commercial handling of meat.
These deviations in postmortem ph decline can arise from a number of. Expeditious prediction of postmortem changes in frozen fish. This study investigated the effects of dietary energy sources on meat quality, post mortem glycolysis and muscle fibre type transformation of finishing pigs. Therefore, enhanced conductivity or impedance is an indirect measurement of enhanced drip loss or muscle softness which is a. The increased acidity of postmortem muscle results from the accumulation of lactic acid, which is formed as glycogen is degraded anaerobic glycolysis to produce atp. Seventytwo barrows with an average body weight of 65. When an animal is harvested for meat, a series of biochemical reactions.
Five intact korean bulls weighing about 550 kg were slaughtered to investigate postmortem glycolysis. A file with the list of fatty acids in meat samples and their content were. To study the effects of glycolysis on tenderness of poultry breast meat, premortem and postmortem glycolysis in muscle tissue was controlled either by epinephrine administration at suitable intervals of time before slaughtering or by allowing the birds to struggle freely just before and during slaughtering. Effects of dietary energy sources on post mortem glycolysis, meat. Rapid andor excessive glycolysis leads to pale, soft, and exudative pse meat, while insufficient glycolysis results in dark, firm, and dry dfd meat. Premortem glycolysis, occurring as a result of death struggle or epinephrine administration 1. In comparison to pigs and poultry, less information is available detailing the regulation of postmortem glycolysis of fish muscle. Rancidity of fat in meat is one of the precursors of flavor metabolites. These limitations likely occur because the term fish meat encompasses a vast number of species consumed for meat. Postmortem regulation of glycolysis by 6phosphofructokinase in bovine muscle. Rapid post mortem glycolysis and high phu values suggest the occurrence of stress at and preslaughter.
Immediately the neck is cut, blood circulation stops, 1. Understanding and utilizing postmortem events and processes. Many workers associated with the meat industry were interested in this post mortem glycolysis process because on occasions something goes wrong. Although many modifications are used, the methods may be divided into two classes, brine and drysalt cures. Irreversible crosslinking of actin and myosin occurs. Greater change in concentration of glucose, g1p, g6p, f6p, lactate in es muscle 2. Postmortem changes in chicken muscle worlds poultry. Regulation of postmortem glycolysis in ruminant muscle. Food, wastes, hormones and metabolites supply stops. The phu of pse pork is similar to that of normal pork.
Glucose increases over 5fold, caused by debranching of glycogen. Our study is in agreement with the results of hill5 hamilton. Characteristics of meat quality and the acceleration of post. Changes in membrane permeability enhance the ion transport i. Glycolic changes which occur postmortem have an impact on the physical and sensory features of beef, which in turn determine the successive processes and influence such beef quality traits as colour, tenderness, and cooling loss. Proteolysis is an important factor contributing to postmortem changes in skeletal muscle, including meat tenderness. Proteolysis is an important factor contributing to post mortem changes in skeletal muscle, including meat tenderness. Unlike mammalian and poultry meat, which shows strong postmortem drop in ph reaching ultimate peak values of about 5.
Influence of post mortem glycolysis and cooling on colour. How to use postmortem data it is difficult to identify when bruising occurs. Annals of the new york academy of sciences 1987, 508 1 physiological, 516522. Effects of dietary energy sources on post mortem glycolysis. As a tissue, muscle has the unique ability to switch its metabolic source of atp, the energy currency underpinning muscle function. Meat tenderness may be improved by accelerating muscle metabolism or by damaging muscle structure and increasing the solubility of muscle proteins. Conversion of chicken muscle to meat and factors affecting. Main changes in post mortem glycolysis post mortem meat glycolysis occurs when o 2 supply to muscle tissue ceases, glycogen, main cho store of animals is no longer oxidized to co 2 and h 2 o but anaerobically broken down to lactic acid. Muscles were kept at different temperatures 0, 20 and 40 c until 4 h postmortem and then stored at 4 c. Premortem glycolysis, occurring as a result of death struggle or epinephrine administration 12 hr before slaughtering, lowered the ph of the meat at the time of death and caused toughness. Added tenderisers augment the action of the muscle enzymes and usually contain the plant protease, papain. In living tissue glycolysis helps generate adenosine triphosphate atp for cellular functions. The rate of post mortem glycolysis may be too fast, leading to a rapid drop in ph typical of pse meat, or too slow, resulting in too high ultimate ph typical of dfd meat knox et al. Empey found that bacteria grow and develop very slowly on meat during rigor, as a ph of approximately 5.
Between lairage pens and the stunning area there was a 5 m single file. In the past it was assumed that the normal post mortem accumulation of lactic acid causes the. High postmortem temperature combined with rapid glycolysis. Two groups of twelve turkey carcasses with sirnilas ultimate ph values were sefected based on 15 min postmonem pm breast muscle ph rapid. It is one of the recognizable signs of death, characterized by stiffening of the limbs of the corpse caused by chemical changes in the muscles postmortem. The history of the development if the modern meat type chicken, the form and function of its muscles, the factors that determine muscle growth and their effects on. Both pse and dfd meat induce significant losses to the meat industry. The aim of this study was evaluation of the postmortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic acid, as well.
Influence of post mortem glycolysis and cooling on colour and colour stability in different muscles of belgian blue beef. Influence of postmortem aging in tenderness of chicken. In experiment 1, longissimus dorsi ld steaks were stored at 3 c for 010 d. Animals that are not handled optimally ante mortem will likely have faster running muscle biochemistry and. Further efforts to understand how the glycolytic enzyme kinetics are influenced by both pre and post slaughter factors will be beneficial in the ongoing quest to maximise fresh meat quality. The aim of this study was to investigate the effects of sex, age and preslaughter conditioning of marketed indigenous south african goats on early post mortem and ultimate ph and temperature, colour and tenderness related properties. Principles of meat science 5th edition, chapter 5, pages 97 to 122.
Postmortem muscle glycolysis and meat quality characteristics. Muscle glycogen declined to about onethird of initial values. Variation in the rate andor the extent of post mortem glycolysis is responsible for a major proportion of the variation in meat whc and color. Characteristics of meat quality and the acceleration of postmortem. This study investigated the effects of dietary energy sources on meat quality, post mortem glycolysis and muscle fibre type. Oxidised deactivated papain can be injected into the blood stream ante mortem or active papain can be applied to meat post mortem. In the past it was assumed that the normal postmortem accumulation of lactic acid causes the.
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