Tenderness and oxidative stability of postmortem muscles. But with increased storage of meat, the acidity of the meat is lessened or the alkalinity increases and ammonia is liberated. Postmortem changes in atp, glucose6phosphate and ph demonstrated that the rate of postmortem glycolysis in the pm was significantly faster than in the ld. Electrical stimulation is known to accelerate post mortem glycolysis and the onset phase of rigor, so that. The full text of the thesis is available as an adobe acrobat pdf.
The requirement for this type of salvage is removal of all exudates and the. Dehydrogenase enzymes associated to glycolysis in beef. Post mortem procedures 11 if a cement floor is available which is rarely the case, this greatly facilitates subsequent disinfection. Anabolism produces chemical compounds from smaller units and requires energy. There is substantial evidence to show that consumers rate.
Most of the glucose in muscle is stored as glycogen. Effects of dietary energy sources on post mortem glycolysis, meat. The gylco stands for glucose, and lysis stands for splitting. They are brought about by enzymes and microorganisms, and by chemical and physical means which alter the structure and chemical composition of the meat muscle in the living animal is 1 pliant, soft. No detectable breakdown products of thick and thin filaments. It must be said however that the real stars of glycolysis are the enzyme since they allow the reactions to be fast and energy efficient.
Glycolysis is the process by which glucose is converted via fructose1,6bisphosphate to pyruvate with the generation of 2 mol atp per mol of glucose. Glycolysis is supremely important in understanding. The glycolysis process is a multistep metabolic pathway that occurs in the cytoplasm of animal cells, plant cells, and the cells of microorganisms. The physiological and metabolic processes that take place in the muscles of living animals, as well as those that take place during rigor mortis and at postmortem in carcasses are discussed. This study investigated the effects of dietary energy sources on meat quality, post mortem glycolysis and muscle fibre type. Differential effects of electrical stunning on the early post.
This study was conducted to assess the regulation of glycolysis by 6phosphofructokinase pfk during the postmortem metabolism of beef muscle. Thus, glycolysis is also the decomposition of glycogen. The importance of meat and meat animals quranic versus. This study investigated the effects of dietary energy sources on meat quality, post mortem glycolysis and muscle fibre type transformation of finishing pigs. Apr 07, 20 the first five reactions of glycolysis are what is referred to as the energy investment phase, since atp is invested into the reactions, the last five reactions are known as the energy payoff phase since it is here that the atp used is regenerated with two extra atp molecules, giving glycolysis a net gain of two atp per molecule of glucose used. Of all eating quality parameters in beef, tenderness has often been described as the most. However, few studies have demonstrated whether the dietinduced change of muscle glycogen is achieved by the transformation of muscle fibre type. The various mechanisms involved in the conversion of muscles to meat and its eventual tenderization are discussed as well. Effects of production systems on the muscle energy status. Well its simple it is a metabolic process that converts a glucose 6 carbons molecule into 2 pyruvate molecules.
Dransfield 1993 has presented a model which quantifies these changes and attempts to predict this increase in muscle tenderness post mortem. Both pse and dfd meat induce significant losses to the meat industry. Two experiments were conducted to investigate the influence of age of mature cows 24 yr, 68 yr, and 1012 yr cows. Causes and contributing factors to dark cutting meat.
Because of protein denaturation, there is exudation of moisture and discoloration. Pse pork shortterm glycogen depletion prior to death. Meat science 11 1984 309 differential effects of electrical stunning on the early post mortem glycolysis in sheep c. Although many modifications are used, the methods may be divided into two classes, brine and drysalt cures. Htlp can potentially change meat tenderness, waterholding capacity and colour due primarily to protein denaturation during the first 5 h post mortem.
Regulation of postmortem glycolysis and meat quality. Glycolysis glycolysis is also known as the emp pathway after the three scientists that figured out the pathway, g. Rancidity of fat in meat is one of the precursors of flavor metabolites. A free powerpoint ppt presentation displayed as a flash slide show on id. Variations in meat quality characteristics negatively impact consumer satisfaction and demand. Cottrell, jeremy james, mcdonagh, m, dunshea, f and warner, r 2008 inhibition of nitric oxide release preslaughter increases post mortem glycolysis and improves tenderness in ovine muscles.
As the temperature is elevated the time for ripening is shortened. So in simple terms, glycolysis is the splitting of glucose. Glycolysis ceased at appreciably higher ph in the potassium chloride mince than in undiluted mince. 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. The effects of postharvest time and temperature on glycolytic potential of beef muscle dana j. Electrical stimulation is known to accelerate post mortem glycolysis and the onset phase of rigor, so that rapid coolingfreezing may be done soon after slaughter, without the risk of cold. There are ten enzymes that catalyze the glycolysis process from beginning to end.
Generates 2 atp molecules, a source of energy for short burst needs only. Connective tissue provides the support at a number of levels via the endomysium, perimysium or epimysium and maintains the integrity of the contractile apparatus made up of myofibrillar proteins such as actin and myosin and important associated proteins such as titin and nebulin. 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. Meat science 11 1984 309 differential effects of electrical stunning on the early postmortem glycolysis in sheep c. May increase rate of glycogenolysis and thereby increase glycolysis. In this work, we studied the post mortem glycolytic behavior including lactate dehydrogenase and three dehydrogenase.
The protein is an excellent source of essential amino acids. Understanding early postmortem biochemical processes. 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. This study showed that the energy status in the muscle post mortem does not influence the tenderness of the meat nor the colour p0. Exploring the role of mitochondria in postmortem meat. Sheep, rabbit and oxmuscle minces prepared soon after slaughter were diluted with 1 vol.
The post mortem oxygen depletion increases the glycolytic activity and lactate production. Poultry meat is also a good sources of phosphorus, iron, chopper, zinc, and vitamins b12 and b6. Postmortem changes in atp, glucose6phosphate and ph demonstrated that the rate of postmortem glycolysis in the pm was significantly faster than in. Postmortem glycolysis is one of the most important factors determining the quality of meat. It is important to understand that it occurs in the. Deep muscles in large carcasses are susceptible to. Rahuls noteblog notes on biochemistry notes on glycolysis.
Since steps 610 occur twice per glucose molecule, this leads to a net production. Catabolism breaks down large molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions. Glycolysis is a group of 10 intracellular cytoplasmic chemical reactions that makes up the most ancient metabolic pathway to synthesize pyruvate and other chemicals that include the energy currency, atp, for the cells existence how interesting. The book covers the gross and detailed composition and structure of muscles and the relationship of the nervous system with the muscular system. Immediately after slaughter, changes occur in the muscle of an animal. Effects of dietary energy sources on post mortem glycolysis. The aim of this study was evaluation of the postmortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic. Metabolism and food chemistry slanker grassfed meat. Regulation of postmortem glycolysis in ruminant muscle. Of the different tests proposed for the detection of incipient putrefaction, baker believes that the determination of ammonical nitrogen has been the most useful and the presence of 0. Because beef is more expensive meat from other species, the beef industry must provide products of consistent quality to meet consumer expectations and be perceived as high value.
Five intact korean bulls weighing about 550 kg were slaughtered to investigate postmortem glycolysis. Animals from the abf production system had the lowest shear force value at 1, 7 and 14 days post mortem and animalsfrom the ap production system had the highest shear force value at 1, 7 and 14 days post mortem. Characteristics of meat quality and the acceleration of postmortem. If glycogen is depleted by chronic longterm stress before slaughter than less lactic acid is formed and the meat does not acidify normally which consequently results in high ph in meat i. Empey found that bacteria grow and develop very slowly on meat during rigor, as a ph of approximately 5.
There are a total of 10 enzymatic reactions involved in this pathway. Rapid andor excessive glycolysis leads to pale, soft, and exudative pse meat, while insufficient glycolysis results in dark, firm, and dry dfd meat. Glycolysis literally means the splitting of 6 carbon glucose into two 3 carbon pyruvates. Postmortem changes in muscle and its conversion into meat. Differential effects of electrical stunning on the early. Over 10 million scientific documents at your fingertips. Steps 1 and 3 consume atp blue and steps 7 and 10 produce atp yellow. Agric production physiology in the department of animal and wildlife sciences university of pretoria pretoria 2011 supervisor. Glycolysis is the process in which one glucose molecule is broken down to form two molecules of pyruvic acid also called pyruvate. Issn 03091740 full text for this resource is not available from the research repository. Meat may be frozen and then stored at temperatures of 10 to 15f.
In experiment 1, longissimus dorsi ld steaks were stored at 3 c for 010 d. If possible, a site for the postmortem remote from contact with other wild animals and domestic livestock should be selected. Principles of meat science 5th edition, chapter 5, pages 97 to 122. At least six enzymes operate in the metabolic pathway. As a tissue, muscle has the unique ability to switch its metabolic source of atp, the energy currency underpinning muscle function.
The inclusion of glycogen, atp, adp, nad or magnesium chloride in the diluent had little effect on the ultimate ph of the diluted mince. A pit may have to be dug to dispose of the carcass, so. An increase in glycolysis results from ex cessive excitement, starving and stress caused by ambient temperature, which in turn leads to high postmortem. If possible, a site for the post mortem remote from contact with other wild animals and domestic livestock should be selected. Since steps 610 occur twice per glucose molecule, this leads to a net production of energy. These changes, like the changes in milk and eggs, can be retarded by method of handling and storage. Sarcoplasmic and myofibrillar protein extmability was reduced for breast samples from rg and dc carcasses as weil as for postrigor mat held at 40c p postmortem glycolysis in ruminant muscle 2014 ferguson, d. It is also important to note that anaerobic glycolysis is significantly less efficient. The characteristic conversion of muscle to meat that occurs post mortem arises due to a series of biochemical and biophysical changes that are initiated upon death. This process occurs in all living cells regardless of the organism. However, many mechanisms of post mortem metabolic regulation have not been fully investigated in beef carcasses.
Postmortem procedures 11 if a cement floor is available which is rarely the case, this greatly facilitates subsequent disinfection. Glucose is a 6 carbon molecule which is broken down into 2 three carbon molecules of pyruvate. 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. Poultry meat meat from chickens and turkeys provides a high quality proteins and low fat.
Up to 24 hours after slaughter, anaerobic glycolysis in muscle generates lactic acid and lowers the ph. Apparatus and process for separating bone fragments. The metabolic pathway of glycolysis converts glucose to pyruvate via a series of intermediate metabolites. Dietary energy source can influence muscle glycogen storage at slaughter. Effect of postmortem changes on meat quality wismer. Mar 17, 2012 after the death of an animal, cell metabolism is controlled locally. Changes in the concentrations of glycogen and lactate and the concentrations of some. Apparatus and process for separating bone fragments, gristle and sinews from meat as the meat is being ground abstract a conventional meat grinder contains a chopper knife and a chopper plate, the chopper knife rides on the inner surface of the chopper plate and directs the bone fragments, sinews and gristle inwardly toward the. 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. Postmortem regulation of glycolysis by 6phosphofructokinase. The length of time required for ripening varies according to the degree of ripened flavor desired, and the temperature at which the meat is stored.
Influence of postmortem muscle glycogen content on the. Effects of dietary energy sources on post mortem glycolysis, meat quality and muscle. Meat quality defined based on ph and colour depending on cattle. Histochemical and meat quality characteristics of longissimus dorsi ld and psoas major pm muscles were made. Minimization of postmortem glycolysis by epinephrine administration more than 5 hr before slaughtering increased the ultimate ph of meat and the tenderness. Pdf regulation of postmortem glycolysis in ruminant muscle. Each chemical modification red box is performed by a different enzyme. In this way the postmortem changes are nearly inhibited.
Chrystall meat industry research institute of new zealand inc, po box 617, hamilton, new zealand received. Seventytwo barrows with an average body weight of 65. Changes in specific myofibrillar proteins during the aging process a. Steaks from more mature cows had an increased p meat came from, the living skeletal muscle cells used energy hydrolyzed atp in order to a reactivate myosin heads b send acetylcholine across the synaptic gap c release calcium ions from the sarcoplasmic reticulum d perform a power stroke to pull on actin a. Influence of postmortem aging in tenderness of chicken breast fillets. Glycolysis as the name suggests, is the breakdown of glucose. 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. No visible degradation of thick and thin filaments. Poultry meat can be sold as whole carcasses or as cut portions.
Time of storage altered the calculated glycolytic potential in this study. Upton sinclair, the jungle 1906 federal meat inspection act of 1906. Researchers have also used muscle glycolytic potential or glycogen. No more was heard of the notion of es of large meat animals until it was resurrected in new zealand carse. Postmortem muscle glycolysis and meat quality characteristics. Mar 16, 2014 glycolysis as the name suggests, is the breakdown of glucose. Muscle and meat biochemistry teaches the different concepts and topics under the eponymous subject. 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. Rigor mortis one of the recognizable signs of death that is caused by a chemical change in the muscles after death, causing the limbs of the corpse to become stiff and difficult to move or manipulate. Glycolysis is a group of 10 intracellular cytoplasmic chemical reactions that makes up the most ancient metabolic pathway to synthesize pyruvate and other chemicals that include the energy currency, atp, for the cells existencehow interesting. Regulation of postmortem glycolysis in ruminant muscle article pdf available in animal production science 544.
128 404 59 374 524 435 890 360 72 1464 1421 453 127 777 1691 1535 713 502 658 223 1328 97 34 1472 785 1210 705 1458 1441 881 1173 1083 1377 676 765 1049