Rigor Mortis Movie Download In Tamil

Rigor mortis[a] (Latin: rigor "stiffness", and mortis "of death"), or postmortem rigidity, is the fourth stage of death. 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 (mainly calcium).[1] In humans, rigor mortis can occur as soon as four hours after death. Contrary to folklore and common belief, rigor mortis is not permanent and begins to pass within hours of onset. Typically, it lasts no longer than eight hours at "room temperature".

After death, aerobic respiration in an organism ceases, depleting the source of oxygen used in the making of adenosine triphosphate (ATP). ATP is required to cause separation of the actin-myosin cross-bridges during relaxation of muscle.[2] When oxygen is no longer present, the body may continue to produce ATP via anaerobic glycolysis. When the body's glycogen is depleted, the ATP concentration diminishes, and the body enters rigor mortis because it is unable to break those bridges.[3][4]

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Calcium enters the cytosol after death. Calcium is released into the cytosol due to the deterioration of the sarcoplasmic reticulum. Also, the breakdown of the sarcolemma causes additional calcium to enter the cytosol. The calcium activates the formation of actin-myosin cross-bridging. Once calcium is introduced into the cytosol, it binds to the troponin of thin filaments, which causes the troponin-tropomyosin complex to change shape and allow the myosin heads to bind to the active sites of actin proteins. In rigor mortis myosin heads continue binding with the active sites of actin proteins via adenosine diphosphate (ADP), and the muscle is unable to relax until further enzyme activity degrades the complex. Normal relaxation would occur by replacing ADP with ATP, which would destabilize the myosin-actin bond and break the cross-bridge. However, as ATP is absent, there must be a breakdown of muscle tissue by enzymes (endogenous or bacterial) during decomposition. As part of the process of decomposition, the myosin heads are degraded by the enzymes, allowing the muscle contraction to release and the body to relax.[5]

Rigor mortis is very important in the meat industry. The onset of rigor mortis and its resolution partially determines the tenderness of meat. If the post-slaughter 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.

The degree of rigor mortis may be used in forensic pathology to determine the approximate time of death. A dead body holds its position as rigor mortis sets in. If the body is moved after death, but before rigor mortis begins, forensic techniques such as livor mortis can be applied. Rigor mortis is known as transient evidence, as the degree to which it affects a body degrades over time.

We studied the persistence of rigor mortis by using physical manipulation. We tested the mobility of the knee on 146 corpses kept under refrigeration at Torino's city mortuary at a constant temperature of +4 degrees C. We found a persistence of complete rigor lasting for 10 days in all the cadavers we kept under observation; and in one case, rigor lasted for 16 days. Between the 11th and the 17th days, a progressively increasing number of corpses showed a change from complete into partial rigor (characterized by partial bending of the articulation). After the 17th day, all the remaining corpses showed partial rigor and in the two cadavers that were kept under observation " outrance" we found the absolute resolution of rigor mortis occurred on the 28th day. Our results prove that it is possible to find a persistence of rigor mortis that is much longer than the expected when environmental conditions resemble average outdoor winter temperatures in temperate zones. Therefore, this datum must be considered when a corpse is found in those environmental conditions so that when estimating the time of death, we are not misled by the long persistence of rigor mortis.

Rigor mortis is conventionally a postmortem change. Its occurrence suggests that death has occurred at least a few hours ago. The authors report a case of "Rigor Mortis" in a live patient after cardiac surgery. The likely factors that may have predisposed such premortem muscle stiffening in the reported patient are, intense low cardiac output status, use of unusually high dose of inotropic and vasopressor agents and likely sepsis. Such an event may be of importance while determining the time of death in individuals such as described in the report. It may also suggest requirement of careful examination of patients with muscle stiffening prior to declaration of death. This report is being published to point out the likely controversies that might arise out of muscle stiffening, which should not always be termed rigor mortis and/ or postmortem.

Organismal death is a process of systemic collapse whose mechanisms are less well understood than those of cell death. We previously reported that death in C. elegans is accompanied by a calcium-propagated wave of intestinal necrosis, marked by a wave of blue autofluorescence (death fluorescence). Here, we describe another feature of organismal death, a wave of body wall muscle contraction, or death contraction (DC). This phenomenon is accompanied by a wave of intramuscular Ca2+ release and, subsequently, of intestinal necrosis. Correlation of directions of the DC and intestinal necrosis waves implies coupling of these death processes. Long-lived insulin/IGF-1-signaling mutants show reduced DC and delayed intestinal necrosis, suggesting possible resistance to organismal death. DC resembles mammalian rigor mortis, a postmortem necrosis-related process in which Ca2+ influx promotes muscle hyper-contraction. In contrast to mammals, DC is an early rather than a late event in C. elegans organismal death. VIDEO ABSTRACT.

Objective measurements were carried out to study the evolution of rigor mortis on rats at various temperatures. Our experiments showed that: (1) at 6 degrees C rigor mortis reaches full development between 48 and 60 hours post mortem, and is resolved at 168 hours post mortem; (2) at 24 degrees C rigor mortis reaches full development at 5 hours post mortem, and is resolved at 16 hours post mortem; (3) at 37 degrees C rigor mortis reaches full development at 3 hours post mortem, and is resolved at 6 hours post mortem; (4) the intensity of rigor mortis grows with increase in temperature (difference between values obtained at 24 degrees C and 37 degrees C); and (5) and 6 degrees C a "cold rigidity" was found, in addition to and independent of rigor mortis.

Calcium salts hasten and magnesium salts retard the development of rigor mortis, that is, when these salts are administered subcutaneously or intravenously. When injected intra-arterially, concentrated solutions of both kinds of salts cause nearly an immediate onset of a strong stiffness of the muscles which is apparently a contraction, brought on by a stimulation caused by these salts and due to osmosis. This contraction, if strong, passes over without a relaxation into a real rigor. This form of rigor may be classed as work-rigor (Arbeitsstarre). In animals, at least in frogs, with intact cords, the early contraction and the following rigor are stronger than in animals with destroyed cord. If M/8 solutions-nearly equimolecular to "physiological" solutions of sodium chloride-are used, even when injected intra-arterially, calcium salts hasten and magnesium salts retard the onset of rigor. The hastening and retardation in this case as well as in the cases of subcutaneous and intravenous injections, are ion effects and essentially due to the cations, calcium and magnesium. In the rigor hastened by calcium the effects of the extensor muscles mostly prevail; in the rigor following magnesium injection, on the other hand, either the flexor muscles prevail or the muscles become stiff in the original position of the animal at death. There seems to be no difference in the degree of stiffness in the final rigor, only the onset and development of the rigor is hastened in the case of the one salt and retarded in the other. Calcium hastens also the development of heat rigor. No positive facts were obtained with regard to the effect of magnesium upon heat vigor. Calcium also hastens and magnesium retards the onset of rigor in the left ventricle of the heart. No definite data were gathered with regard to the effects of these salts upon the right ventricle.

Issues are raised by the persistent concern with achieving rigor in qualitative research, including the rigidity that often characterizes the search for validity in qualitative work and the threat to validity that the search for reliability may pose. Member validation is highlighted as a technique that exemplifies not only the practical, but also the profoundly theoretical, representational, and even moral problems raised by all procedures aimed at ensuring the trustworthiness of qualitative work.

Introduction

What is rigor?

What causes rigor?

How long docs a fish stay inrigor?

How does rigor affect handling andprocessing?

Controlling the effects ofrigor

Thaw rigor

Can thaw rigor beprevented?

Does rigor affect the quality ofsmoked fish?

Which is best, freezing beforerigor, in rigor or after rigor?

Summary

IntroductionThis advisory note explains briefly what rigor is, how itoccurs and how it can affect the quality of fish. The effects of rigor on thehandling and processing of fish, particularly frozen fish, are described indetail. The note recommends a number of ways in which adverse effects on qualitycan be reduced or prevented by correct handling before, during and after theonset of rigor.Although the information given refers mainly to cod, all whitefish behave in a similar way, and the advice should prove of value to allfishermen and processors who are concerned with the processing of newly caughtwhite fish, either at sea or on shore.Rigor is only one factor among many that can affect thequality of fish frozen very soon after capture; other factors, for example blooddiscoloration, are not discussed here. General advice on the freezing of fish atsea is given in Advisory Note 34, and on the handling of blocks of sea-frozenfish in Advisory Note 2. What is rigor?Rigor or, to give it its full name, rigor mortis means thestiffening of the muscles of an animal shortly after death. The word rigor isused throughout this note because it is shorter and easier to use than eitherdeath stiffening or rigor mortis.Immediately after death the muscles of an animal are soft andlimp, and can easily be flexed; at this time the flesh is said to be in thepre-rigor condition, and it is possible to make the muscles contract bystimulation, for example by means of an electric shock.Eventually the muscles begin to stiffen and harden, and theanimal is then said to be in rigor. The muscles will no longer contract whenstimulated, and they never regain this property.After some hours or days the muscles gradually begin to softenand become limp again. The animal has now passed through rigor, and the muscleis in the post-rigor condition. Sometimes rigor is said to be resolved; this issimply another way of saying that the muscle has passed through rigor to thepost-rigor stage,Rigor in fish usually starts at the tail, and the musclesharden gradually along the body towards the head until the whole fish is quitestiff. The fish remains rigid for a period which can vary from an hour or so tothree days, depending on a number of factors described later, and then themuscles soften again. What causes rigor?Rigor results from a series of complicated chemical changes inthe muscle of a fish after death; the process is not yet fully understood, andresearch is still going on, but it is known that factors like the physicalcondition of the fish at death, and the temperature at which it is kept afterdeath, can markedly affect the time a fish takes to go into, and pass through,rigor.While the fish is alive, cycles of chemical changes take placecontinuously in the muscle; these provide energy for the muscle while the fishis swimming, and also produce substances necessary for growth and replacement ofworn-out tissue. The compounds that bring about, and control, these changes areknown as enzymes.The enzymes in the flesh go on working even after the fish isdead, and some of them act on those substances that normally keep the musclepliable and lifelike. During life the muscle would contract and become rigid ifits two main protein components were allowed to interact and bond together, butthe bonding is prevented by the presence of substances that keep the musclepliable, rather like the way in which oil lubricates the moving parts of amachine and prevents it from seizing up.For so long as the muscles contain a reserve of energy, thesesubstances can be replaced by one set of enzymes as fast as they are destroyedby another; thus the muscles stay pliable for a time after death. But once theenergy reserves are used up, the replacement stops and depletion results. Theprotein components are then able to interact, the muscle attempts to contract,and it eventually becomes hard and rigid.The interaction of the protein components is also influencedby the accumulation of lactic acid, which is produced in the muscle when theenergy reserves break down. The relative importance of the two factors,depletion of one set of substances and accumulation of another, is not fullyunderstood, but they are known to vary with the type of animal and with how wellnourished and rested it was at the time of death. How long docs a fish stay inrigor?The time a fish takes to go into, and pass through, rigordepends on the following factors: the species, its physical condition, thedegree of exhaustion before death, its size, the amount of handling during rigorand the temperature at which it is kept.Species: Some species take longer than others to go intorigor, because of differences in their chemical composition. Whiting, forexample, go into rigor very quickly and may be completely stiff one hour afterdeath, whereas redfish stored under the same conditions may take as long as 22hours to develop full rigor. Trawled codling, 18-22 inches long, gutted andstored in ice, usually take 2-8 hours to go into rigor.Condition: The poorer the physical condition of a fish, thatis the less well nourished it is before capture, the shorter will be the time ittakes to go into rigor; this is because there is very little reserve of energyin the muscle to keep it pliable. Fish that are spent after spawning are anexample.Degree of exhaustion: In the same way, fish that havestruggled in the net for a long time before they are hauled aboard and guttedwill have much less reserve of energy than those that entered the net justbefore hauling, and thus will go into rigor more quickly.Size: Small fish usually go into rigor faster than large fishof the same species.Handling: Manipulation of pre-rigor fish does not appear toaffect the time of onset of rigor, but manipulation, or flexing, of the fishwhile in rigor can shorten the time they remain stiff.Temperature: This is perhaps the most important factorgoverning the time a fish takes to go into, and pass through, rigor because thetemperature at which the fish is kept can be controlled. The warmer the fish,the sooner it will go into rigor and pass through rigor. For example, gutted codkept at 32-35F may take about 60 hours to pass through rigor, whereas thesame fish kept at 87F may take less than 2 hours.To sum up, small fish with low reserves of energy, that isexhausted and in poor condition, and kept at a high temperature will enter andpass through rigor very quickly. On the other hand, large, rested, well-fed fishkept at a low temperature will take a very long time to enter and pass throughrigor.The following table gives some indication of rigor time fordifferent species. All times are from direct observation, but the limits are notfixed and it is more than likely that times outside these limits could be metwith in practice. For instance, some fish may already be in rigor when they arelanded on the deck of the fishing vessel either because they have completelyexhausted themselves struggling in the net, or because they have died throughasphyxiation perhaps as much as three hours before the trawl washauled. Species

Temperature

Time from landing on deck to entering rigor

hours

Time from landing on deck to end of rigor

hours

trawled cod

in ice

2-8

20-65

4-8

54-64

42-44

2-5

16-20

1-2

rested cod from aquarium

14-15

72-96

trawled redfish

in ice

120

trawled whiting

in ice

trawled plaice

in ice

7-11

54-55

trawled coalfish

in ice

110

trawled haddock

in ice

2-4

How does rigor affect handling andprocessing?Although the problems of rigor also affect processing in themeat and poultry industries, the problems in the fish industry are more acutebecause we have no control over the nutritional condition or the degree ofexhaustion of the fish before they come on board the vessel. Rigor createsproblems mainly for those sections of the industry concerned with freezing fishat sea, either as whole fish or as fillets, and for those who handle very freshinshore fish at the port for freezing very soon after landing. Rigor problemsare not normally encountered when handling the bulk of the chilled wet fishlanded at the ports, because this fish will already have passed through rigorwhile in ice on board ship. The only time when problems could occur with wetfish is when they have been left lying on deck at a high temperature until theyhave gone into rigor. The explanation of this is given later.Rigor affects frozen whole fish and frozen fillets indifferent ways:FROZEN WHOLE FISHRigor can affect the quality of whole fish in three main ways,by causing gaping in wet and frozen fish, and toughness and excessive drip losson thawing in frozen fish.GapingA fillet is said to gape when the individual flakes of musclecome apart, giving the fillet a broken and ragged appearance. This happens whenthe material that binds the flakes together, known as connective tissue, breaksdown. There appear to be several causes of gaping, one of which is the rigorprocess. As muscle goes into rigor, it attempts to contract but, because theskeleton and the connective tissue prevent contraction, tension increases withinthe muscle. As long as the connective tissue can withstand this increase intension, the flesh will not gape, but when the tension becomes greater than theinherent strength of the connective tissue, some gaping will occur.The temperature of the whole fish as it goes into rigor canhave a marked effect on the amount of gaping; the higher the temperature when itgoes into rigor, the greater is the rigor tension and the weaker the connectivetissue becomes. Thus the higher the temperature the more the flesh will gape.Furthermore, with cod, there is a critical temperature of about 63 F,above which the contractions become so strong and the connective tissue so weakthat the tissue breaks down completely, resulting in a fillet so ragged that itis completely unacceptable. Below 63F, the lower the temperature the lessdamage is done by the contractions. Other species also have criticaltemperatures, not necessarily the same as for cod. This gaping is apparent onfilleting, whether or not the fish has been frozen and thawed, but is worse infrozen fish, whether frozen in rigor or after rigor.Strangely enough, if the temperature is lowered so much thatthe fish starts to freeze while it goes into rigor, the connective tissue isagain weakened, this time by the formation of ice, and gaping occurs. Gapingcaused by freezing fish that are going into rigor is more likely to occur inwell-nourished fish, where the contractions are stronger than in spentfish.Rough handling of fish in rigor can also cause gaping, becauseany attempt to bend a rigid fish will break the muscle or the connective tissue.Damage of this kind is most likely to happen when the fish are being loaded intofreezers at sea, and attempts are made to straighten bent fish while they arestiff. Pressure from the freezer plates can also damage rigid fish lying indistorted positions in the freezer.Rigor, however, is only one of several causes of gaping, sincegaping is often seen in fillets taken from whole fish frozen post-rigor, andalso in wet fish that have never been frozen. Here gaping is due to prolongedstorage, and the longer the fish has been kept the worse it becomes. Some fishare inherently softer than others, and simply handling the fish during freezing,thawing and filleting can cause considerable gaping. Softness of the flesh canbe influenced by the type of feeding, the fishing ground and the stage in thespawning cycle. All these factors may be superimposed on the gaping caused byrigor, thereby making it worse.Gaping due to rigor, then, is most likely to occur in well-fedfish kept at a high temperature and then frozen after they have started to gointo rigor, or in fish that are roughly handled while they are inrigor.Toughness and drip lossThe higher the temperature at which a fish goes into rigor,the greater will be the drip loss on thawing and, when the fish is cooked andeaten, it will be tough and stringy; this effect will probably be aggravatedwhen the fish are well fed and not exhausted. However, it is not rigor alonethat causes toughness and high drip loss in thawed frozen fish; the flesh may beinherently tough or it may have been toughened by incorrect freezing, coldstorage or thawing.Whole fish frozen pre-rigor tend to have a higher drip lossthan similar fish frozen in rigor or post-rigor, but this may be due to what isknown as thaw rigor, which is explained later.FROZEN FILLETSUnless precautions are taken, fillets cut from a fish beforeit goes into rigor will shrink; the shape of the fillet then becomes distortedand the surface of the flesh takes on a corrugated appearance. These distortionswill remain throughout subsequent freezing and thawing.When a whole fish goes into rigor, the muscle tries tocontract but is prevented from doing so by being anchored to the rigid skeleton,thus setting up the stresses that lead to gaping but, as soon as the fillet iscut off, the restraint of the skeleton is removed and the filletshrinks.The extent of the shrinkage depends on the condition of thefish and on the temperature at which it is kept. When a fillet is cut from awell-fed, pre-rigor fish and then kept at a high temperature before freezing, itmay shrink by as much as 30-40 per cent of its original length; on the otherhand, a fillet taken from a pre-rigor fish in poor condition and then frozen atonce will hardly shrink at all.Since we have little control over the condition of the fish,except by avoiding fishing grounds where fish in poor condition are likely to befound at certain seasons, it is very important that fillets be frozenimmediately after they have been cut from pre-rigor fish. If delay betweenfilleting and freezing is unavoidable then the fillets must be kept chilled toreduce shrinkage, but even at 32F some of the fillets will shrink after atime. Immediate freezing is the only safe way to avoid shrinkage. Pre-rigorfillets should not be chilled by means of fresh water or freshwater ice;shrinkage is increased by contact with fresh water.The cut surface of a pre-rigor fillet is different from thattaken from a post-rigor fish; it is dull, rough and corrugated, with a texturethat feels like crepe rubber, caused by exposure of the cut ends of individualmuscle fibres. Pre-rigor fillets are unsuitable for smoking because the rough,dull surface does not take on a good gloss during the process.When filleting is delayed until after the whole fish has goneinto rigor at a low temperature, most of the problems of shrinkage are avoided,but nevertheless there are some disadvantages. Mechanical filleting is oftendifficult when fish are in rigor, and even hand filleting may give a slightlylower yield from fish in rigor compared with fish that are soft and flexible. Inaddition, gaping may be caused by forcibly straightening bent fish beforecutting them, and chilled buffer storage space has to be provided to keep thewhole fish until they go into rigor.Frozen fillets taken from post-rigor whole fish are normallyof uniformly good quality, provided the whole fish has been properly handled andkept chilled; the main disadvantage is the long time in buffer storage, up tothree days, which makes extra demands on space and labour.Rigor affects the toughness of, and drip loss from, frozenfillets in the same way as with whole fish; the warmer the fish when it goesinto rigor, the greater will be the drip loss and the tougher will be the cookedfillet. Just as with frozen whole fish, pre-rigor frozen fillets will lose moredrip than comparable fillets frozen in rigor or after rigor. Controlling the effects ofrigorThe safest and most reliable way of avoiding the undesirableeffects of rigor is to keep the fish chilled at every stage before freezing.Provided the fish pass through rigor at a low temperature, the effect of rigoron quality will not be serious.Having said that, it is necessary to mention the possibilityof accelerating the rigor process by raising the temperature of the fish undercarefully controlled conditions. It is possible by warming a fish to shorten thetime it takes to go into, and pass through, rigor; the space required for bufferstorage can thus be reduced, but only at the expense of some loss of quality dueto the higher temperature, and the possibility of increased gaping. As explainedearlier, the maximum temperature for accelerating rigor in cod is 63F ifirreparable damage is to be avoided. On the whole it is probably safer incommercial practice at sea not to attempt acceleration of rigor, but to keep thefish chilled until they enter the freezer. Thaw rigorWhen muscle is frozen pre-rigor and kept for a short time incold storage, it is still able to contract and go into rigor after thawing. Thisis known as thaw rigor and, when the thawing is done rapidly at a hightemperature, the muscle can then suffer from the defects associated with hightemperature rigor.Thaw rigor is rarely a problem in thawed whole fish becausefreezing and cold storage have usually sapped the energy reserves sufficientlyto weaken the contractions in the muscle; the skeleton restrains the muscle butthe stresses are insufficient to break the connective tissue. If damage is seenat all in thawed whole fish, it usually occurs near the tail, where thawing ismost rapid.However, when pre-rigor fillets are thawed, the muscle is freeto shrink as soon as the ice within the flesh has melted, and the fillets becomeshrunken and corrugated and lose a large amount of drip. The effects are mostsevere when the pre-rigor muscle is cooked from the frozen state, as, forexample, when consumer packs of fillets or fish fingers are prepared frompre-rigor fish. When a fish finger is given a preliminary cook, the flesh cancontract and cause the fish finger to distort, resulting in difficulty inpacking. The texture will be tough and stringy and drip loss will be high. Onfinal cooking, the free water will boil off and cause the batter to spatter.Thaw rigor is not of course the only source of free water in frozen fillets andfish fingers. The effects of thaw rigor are more noticeable when single filletsor small portions are thawed, rather than blocks of fillets. Can thaw rigor beprevented?Thaw rigor is uncommon in commercial practice but, when it ismet with, the ill effects can be avoided fairly simply. The simplest way is toextend the cold storage time of the stock of pre-rigor fish. Provided they arekept for at least eight weeks at minus 20 F, the flesh has time to passthrough rigor in the frozen state; this has no bad effect on the quality ofeither whole fish or fillets, since they are both held rigidly enough whilefrozen to prevent the muscle from contracting.If the fish have to be taken out of store in less than eightweeks, they should be thawed slowly at room temperature; in this way rigor iscompleted while the fish are in a semi-frozen state, thus preventing severecontraction of the muscle. Does rigor affect the quality ofsmoked fish?Fillets from fish frozen whole before rigor should yield asmoked product of excellent quality provided thaw rigor effects are avoided.Fillets from whole fish frozen during or after rigor should also yield a goodsmoked product, provided gaping has been avoided.Frozen fillets are not normally smoked, since they do not makesuch a good smoked product as fillets from thawed whole fish; pre-rigor filletsare particularly difficult to smoke satisfactorily, because they fail to take agood gloss due to the rough texture of the cut surface. Pre-rigor fillets fromvery fresh inshore fish should not be smoked, since treatment in the kiln cancause high temperature rigor effects, resulting in very shrunken smokedfillets. Which is best, freezing beforerigor, in rigor or after rigor?There is no one simple answer to this question, since thereare arguments for and against freezing at any of these stages. None of the threestages of rigor is clearcut; the process is a gradual one, beginning from themoment the fish dies, and the effects of rigor are therefore very much a matterof degree.On the freezer trawler the answer really is to have aprocessing system that is sufficiently flexible to handle properly fish in anystage of the rigor process, and a reliable labelling scheme that enables shorefactories to identify fish frozen pre-rigor, in rigor or after rigor, so thatthe raw material can be handled appropriately.The following table lists the advantages and disadvantages offreezing whole fish or fillets in all three conditions of rigor:Frozen whole fish

advantages

disadvantages

frozen pre-rigor

buffer store not required

no gaping, except possibly from thaw rigor

thaw rigor gaping possible

high drip loss may occur

large processing capacity required to cope with high catchingrates

frozen in rigor

uniformly good quality obtainable generally

buffer store required

texture variation possible

gaping or broken fillets when fish are forcibly straightenedor rigor temperature is high

pack less well in freezer

frozen post-rigor

uniformly good quality obtainable generally

danger of contraction damage avoidable

buffer store required

gaping may occur when held too long or at too high atemperature before freezing

Frozen fillets

advantages

disadvantages

frozen pre-rigor

buffer store not required

fillets can be cut by hand or machine

large processing capacity required to deal with high catchingrates

fillets shrink when awaiting freezing or afterthawing

rough cut surface

particularly unsuitable for smoking

may be high drip loss

frozen in rigor

excellent quality possible

no shrinkage

buffer store required

difficult to fillet by machine or by hand

less yield from hand filleting

usually unsuitable for smoking

bent fish yield gaping fillets

frozen post-rigor

uniformly high quality

no shrinkage

machine or hand filleting

large buffer store required for up to 3 days

usually unsuitable for smoking

SummaryRigor changes occurring in fish before it is frozen may affectthe quality in three main ways:1. toughness and high drip loss in frozen wholefish or fillets;

2. gaping in fillets taken from frozen whole fish;and

3. shrinkage of frozen fillets.These undesirable effects can be reduced or preventedby:1. keeping the fish cool, particularly before it goes intorigor;

2. handling it carefully when in rigor; and

3. freezing fillets taken from pre-rigor fish as soon as theyare cut.Careful treatment of the fish before and during rigor willresult in a higher quality frozen product with a correspondingly better marketvalue.