Postmortem inspection food safety and inspection service. The accumulation of lactic acid lowers down the muscle ph, which is an important postmortem change during the conversion of muscle to meat. Regulation of postmortem glycolysis and meat quality. To elucidate the molecular mechanism underlying this fast glycolysis in muscle to become pse meat, post mortem atp metabolism, fructose2,6diphosphate content, and the activities of ampk. Dec 09, 2017 pressure treatment meat is subjected to shock when submerged in water, the treatment subjects meat to very high pressure, accelerates postmortem glycolysis and cause improvement in tenderness. Pale, soft, and exudative pse meat has been recognized for decades. Postmortem muscle glycolysis and meat quality characteristics of. Postmortem regulation of glycolysis by 6phosphofructokinase in bovine muscle. These animals become easily stressed preslaughter, which leads to exaggerated glycolysis, an increase in body temperature, and higher production of lactic acid. Presented at the 55th international congress of meat science and technology.
Summary a brief period of electrical stimulation of freshly slaughtered lamb carcasses by 250 v pulses is shown to increase subsequent rates of postmortem glycolysis and hasten rigor onset. 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. Fast glycolysis during early postmortem stage while the muscle temperature is still high is the cause of pse meat. Pigs susceptible to porcine stress syndrome, or pss, have an increased likelihood of developing pse meat. Rigor mortis was loosened in 174 joints of 44 deceased persons between 7. Effects of dietary energy sources on post mortem glycolysis. Nevertheless, capn3, especially those associated with the sarcoplasmic reticulum sr membrane kramerova et al. Influence of post mortem glycolysis and cooling on colour and colour stability in different muscles of belgian blue beef. We thus investigated the differences in meat quality, adenosine phosphates, glycolysis, and bound key enzymes associated with glycolysis.
The aim of this study was evaluation of the post mortem changes in bovine meat during aging. Regulation of post mortem glycolysis in ruminant muscle. However, few studies have demonstrated whether the dietinduced change of muscle glycogen is achieved by the transformation of muscle fibre type. Dietary energy source can influence muscle glycogen storage at slaughter. It allows meat to reach acceptable eating quality in significantly shorter period of time. 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. If the postslaughter meat is immediately chilled to 15 c 59 f, a phenomenon known as cold shortening occurs, whereby the muscle sarcomeres shrink to a third of their original length. Preslaughter transport effect on broiler meat quality and post mortem glycolysis metabolism of muscles with different fiber types. Animals that are not handled optimally antemortem will likely have faster running muscle biochemistry and.
Further efforts to understand how the glycolytic enzyme kinetics are influenced by both pre and postslaughter factors will be beneficial in the ongoing quest to maximise fresh meat quality. In this way the post mortem changes are nearly inhibited. Low salt pigmeat products and novel formulations slu. Changes in the post mortem physical characteristics of muscle have long been associated with lactic acid production from post mortem glycolysis. The working hypothesis for this objective is increased levels of phosphocreatine in the muscle of pigs immediately prior to processing extends postmortem glycolysis. Increases also took place in 3phosphoglycerate, 2phosphoglycerate and phosphoenolpyruvate, but not in pyruvate. Stimulated carcasses put into a blast freezer at 5 hr postmortem were as tender as untreated carcasses held for 16 hr before freezing to avoid toughness caused by postmortem shortening. In post mortem muscle, the tissue attempts to maintain homeostasis by preserving atp concentration.
In some species of fish, the final ph may be lower. Preslaughter transport effect on broiler meat quality and. To elucidate the molecular mechanism underlying this fast glycolysis in muscle to become pse meat, postmortem atp metabolism, fructose2,6diphosphate content, and the activities of ampk. Post mortem glycolysis results in the accumulation of lactic acid which in turn lowers the ph of the muscle. This is caused by preslaughter stress and, as the term suggests, results in a darker meat with undesirable meat quality characteristics. 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. Very rapid glycolysis due to excitement antemortem or due to holding on kill floor a long time before chilling postmortem. The effects of antemortem 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. 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. Preslaughter transport has been reported to decrease the quality of breast meat but not thigh meat of broilers. Two recent studies have highlighted the potential to improve meat quality through inclusion of specific compounds in the diet immediately prior to slaughter that modify postmortem glycolysis. Meat tenderness may be improved by accelerating muscle metabolism or by damaging muscle structure and increasing the solubility of muscle proteins. Nutritional influences on pork quality hogs, pigs, and pork.
Any deviation from the normal rate and extent of postmortem glycolysis and ph decline may lead to poor meat quality development such as pale soft and exudative pse meat, acid meat, or dark firm and dry meat dfd briskey, 1964. Influence of post mortem glycolysis and cooling on colour. There is substantial evidence to show that consumers rate. The postmortem changes that take place when muscle is converted into meat have a marked effect on the quality of the meat. Horgan dj, kuypers r 1985 postmortem glycolysis in rabbit longissimus dorsi muscles following electrical stimulation. Influence of postmortem muscle glycogen content on the. 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 in meat ph result from post mortem metabolism glycolysis and the conversion of glycogen into lactic acid. Principles of meat science 5th edition, chapter 5, pages 97 to 122. Fragmentation of chicken myofibrils american meat science. Regulation of postmortem glycolysis in ruminant muscle 2014 ferguson, d. Pdf regulation of postmortem glycolysis in ruminant muscle. In this way the postmortem changes are nearly inhibited. It also prevents cold shortening by accelerating post mortem glycolysis and onset of rigor mortis before chilling temperatures reach cold shortening range. This lactate accumulates in the postmortem muscle, and leads to a very low ph.
Meat may be frozen and then stored at temperatures of 10 to 15f. The relationship between glycogen phosphorylase activity and phosphorylation levels in the longissimus thoracis muscle postmortem was studied. The aim of this study was evaluation of the postmortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic. The impacts of accelerated ph decline combined with high muscle temperature on post mortem muscle metabolism and subsequent meat quality attributes have been extensively studied. No detectable breakdown products of thick and thin filaments. Effects of dietary energy sources on post mortem glycolysis, meat. A number of other dietary components have been reported to improve meat quality. Goals objectives we plan to test our central hypothesis by. Postmortem glycolysis in rabbit longissimus dorsi muscles following electrical stimulation. Jun 12, 2019 unlike mammalian and poultry meat, which shows strong postmortem drop in ph reaching ultimate peak values of about 5. Postmortem changes and meat quality questions and study guide. Because glycolysis has the potential to affect meat quality attributes either positively or negatively, evaluating its regulation postmortem is.
Various workers have investigated methods of altering the glycogen content of muscle at the time of slaughter in an effort to regulate the characteris tics of chilled uscle. Changes in specific myofibrillar proteins during the aging process a. How to use post mortem data it is difficult to identify when bruising occurs. Technology of meat, poultry, fish and seafood products module. To elucidate the molecular mechanism underlying this fast glycolysis in muscle to become pse meat, post mortem atp metabolism, fructose2,6diphosphate content, and the activities of ampk, glycogen. Start studying postmortem changes and meat quality. Traditionally, this phenomenon has been observed in pork muscles, primarily due to the relatively fast post mortem glycolysis rate and its relationships to stress susceptibility of pigs before slaughter.
No visible degradation of thick and thin filaments. Seventytwo barrows with an average body weight of 65. Fastfrozen muscle metabolized at a faster rate on thawing. Conversely, prevention of post mortem glycolysis with either epinephrine.
A new insight into the role of calpains in postmortem. This study investigated the effects of dietary energy sources on meat quality, post mortem glycolysis and muscle fibre type transformation of finishing pigs. Effects of post mortem glycolysis on the quality of hotdeboned bovine muscle. However, tissuespecific difference in glycogen metabolism between breast and thigh muscles of transported broilers has not been well studied. Infusing calcium can increase tenderness and increased proteolysis or increased postmortem glycolysis can all be the potential causes. Preslaughter transport effect on broiler meat quality and postmortem glycolysis metabolism of muscles with different fiber types. Postmortem muscle glycolysis and meat quality characteristics of intact male korean native hanwoo cattle. Although many modifications are used, the methods may be divided into two classes, brine and drysalt cures. Regulation of postmortem glycolysis in ruminant muscle. Because postmortem glycolysis and ph decline are enzymatically controlled, evaluating. Effect of some antemortem stressors on perimortem and. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Control of postmortem muscle energy metabolism in pigs.
It is also important to note that anaerobic glycolysis is significantly less efficient with respect to the amount of atp produced by one molecule of glucose. Consequently, muscle glycogen is metabolized via anaerobic glycolysis, which is less efficient at generating atp. On thawing, most of the chemical changes were similar to those in unfrozen muscle post mortem, but took place much more rapidly. In particular, the halothane gene, hal, induces pss in swine. Fast glycolysis during early post mortem stage while the muscle temperature is still high is the cause of pse meat. 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.
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