changes occurring during rigor mortis and subsequent ripening of muscle tissues

Prévia do material em texto

CHANGES O C C U R R I N G 0Vi ) lWG B I C M # O R T l S 
A N D SUBSEQUENT RIPENING OF HUSCLE TISSUES 
ERNEST J. B R I S K E Y ' 
U N I V E R S I T Y OF W I SCONSIN -"--"-----"---"-----"-"----"----"".---"--------"---- 
In presenting this report especial acknowledgment should be given 
the major contributions 8nd reviews of the tlistinguished scient is ts : Dr. E. C. Ba te-mth; Dr. J. R e Bendall and Drr R. A. Iamie, ImTemper- 
ature Research Station, Uhiversity of Cambridge and Department of Scien- 
t i f i c and Industrial Research; Dr. B. B. Marsh 08 the *at Industry Re- search Ins t i tu te of New Zealand; D r r A. Szent-Gyorgyi formerly of Budapest 
and more recently a t Marine Biological Zaboratory, Massachusetts; Dr. F, E. 
Deatherage, Ohio State University; Drr Feiner Hamu, German Meat Research 
Inst i tute; Dr. Jorgen Udvigsen of the Danish Royal College of Agriculture; 
and Dr. Eugene Wierbicki, formerly of Ohio State University, as well as 
many others. These names, I am sum, are familiar to a l l of you. 
Muscle Stiffening : 
Post-mortem t issue changes are very coqplex. The most obvious of 
these changes is the s t i f fening of the xtnasculature o r r igor mortis, 
quently t h i s process is conf'used with the "sett ing of the fat," however, it 
should be regarded as a manifestation of muscular contraction, extenaion 
and chemical degradation. 
Fre- 
Theories of Rigor Mortis: 
Before considering the fbdatnentals of the physical and chemical 
changes, it would perhaps be best t o look at 8 few of the former concepts as 
w e l l as 8ome of the las t ing theories of r igor mortis. 
1, In 1864, &e suggested that the s t i f fening was due t o the 
spontaneous coagulation of the wscle plasma by a process 
akin t o the coagulation of the blood. 
2. This theory received modification in 1862 by Schipiloff who 
suggested that the precipitation of the proteins was due t o 
the l a c t i c acid produced after death. 
3, This acidi ty theory was f'urther substantiated i n 1919 by von 
F k t h , who regarded pH, specifically, as the actual cause of 
r igor mortis . 
4, In 1926 Hoet and Elsrks postulated a t h i r d change suggesting 
tha t both stiffeniw and acid production were related t o the loss of glycogen and/or of creatine phosphate. 
later investigation by Engeulardt (1939) led t o the c lass ica l 
discovery of the ATPase ac t iv i ty of the s tmc tu ra l protein 
5. 
109. 
myosin. 
loss of ATP from the muscle a f t e r death which was most closely 
related t o the onset of st iffening. Also during the early 
for t ies , Szent-Gyt;rgyi and h i s colleagues were making great 
strides in their studies of the s tmcture of muscle and the 
mechanism of contraction and rigor. He considered myosin A 
(Szent-G$rgyi, 194.5), actin, ATP, K, Ca and Mg ions as es- 
sen t i a l components of the m s c l e system. In resting muscle 
myosin A was considered t o be present as a stable complex with 
a par t icular coqlement of K, Cay Mg and A!LT which is un- 
combined with actin. The ac t in is i n the fibrous form. He 
theorized that a post mortem stimulus dislodges part of the 
combined K, and also part of the combined ATP. 
potassium (by diffusion) and ATP (by enzymatic breakdown) are 
removed from miyosin A, as occurs when the muscle dies, ac t in 
combines with myosin A t o form acto-1Pyosiny which, i n the 
absence of ATP is extended and confers on dead muscle the 
r ig id i ty character is t ic of rigor mortis. 
In 1943, E r d b demonstrated that it was actually the 
If, then, both 
6. In 1948, Bate-Smith put for th s t i l l another theory based on 
the interf i lamentary reactions during rigor. Essentially, his 
reasoning is as follows: 
solutione, although uniform i n properties, are not necessarily 
composed of homogeneous molecules. 
r igor mortis involves the association of these filaments by 
weak cross linkages. Thirdly, the cross linkages, which 
account a l so for the decreased extensibi l i ty of the muscle, 
must be formed as a resu l t of total removal of ATP. 
Firs t , par t ic les present i n m s i n 
Secondly, the process of 
Stages of Rigor Mortis: 
The mrkers, Bate-Smith and Bendall (1949) have also described 
four stages of r igor morkis. 
(1) a 'delay period' during which the modulus of e l a s t i c i t y e i the r does not 
change at a l l o r increases very slightly, and (2) a phase i n which it in- 
creases rapidly t o i t s maximum which may be 10 t o 40 times greater than the 
i n i t i a l value. This second phase w i l l be referred t o as the 'rapid phase'. 
Considerable shortening sonetimes occurs during the rapid phase of rigor, 
but this shortening is not a necessary concomitant of stiffening. 
dependent however upon temperature and pH, and according t o Bendall (1951) 
and Mrsh (1954) is most marked a t high tern ratures (above 90° F. and i n 
exhausted animals (pH values above 6 .5 ) . & most obvious physical change 
occurring during the onset of r igor mortis is an increase i n the modulus of 
e l a s t i c i ty , which i n rabbit psoas muscle was fmnd by these workers t o rise 
from 500 t o values of about 10,000. Marsh (1954) found that i n beef the 
modulus rises from a mean i n i t i a l value of 1100 t o a mean f ina l value of 
20,000 t o 30,000. Likewise, a shortening i n length accompanied the change 
i n e l a s t i c i ty . A lengthening of up t o 4% also occasionally preceded the on- 
s e t of rigor. In a l l cases, whether shortening accompanied the onset of 
rigor mortis o r not, rigor was resolved within a few hours of i t s onset, 
the mscle losing the firm, hard appearance of the r i g o r s t a t e . 
mechanisms involved he= axe quite obscun?. 
In these types there were two d i s t inc t phases: 
It is 
The 
Chemical Changes LurLng Rigor : 
Now l e t us consider the effect of several chemical constituents on 
the changes during r igor mortis. 
In 1951 Bendall showed that i n rabbit muscle the creative phos- 
phate level is high immediately post-mortem, but decreases rapidly there- 
after and i s Educed t o less than 20s of i t s i n i t i a l level at about pH 
6.60 betore there is any appreciable loss of ATP. The disappearance of ATP, 
once started, proceeds at a steady rate u n t i l l e s s than 305 of the resting 
amount remains. 
25% level. It has been suggested that the rate of turnover of ATP, there- 
fore, determines the rate of glycolysis. 
breakdown of ATP is exactly balanced by i ts resynthesis from the glycolytic 
cycle. The rapid phase of r igor occurs when the reserve of glycogen i n the 
muscle is almost exhausted, resynthesis being unable t o keep pace with the 
breakdown. 
The rate subsequently decreases and is very slow below the 
During the delay period, the 
In essence, the main chemical changes i n the muscle a f t e r death 
a m the production of l ac t i c acid by anaerobic glycolysis, the breakdown of 
creatine phosphate and the resynthesis and the breakdown of ATP. 
glycolysis and the breakdown of creatine phosphate are mechanisms f o r t h e 
resynthesis of ATP from ADP. 
thesized f o r every molecule of l ac t i c acid formed. 
Both 
One and one half molecules of ATP are resyn- 
Slide I -- The first slide taken f r o m par t of Lawrie's work, 1953, 
I think demonstrates veiy clearly the relationships of the constituents 
discussed. 
phate, a slow and then rapid decrease i n adenosine triphoephate, accompanied 
by a parallel drop i n pH. 
low there is a rapid decrease i n extensibil i ty. 
Immediately a f t e r death there is a rapid drop i n creatine phos- 
After about $ hours when all three values are 
This balance between breakdown and resynthesis can be maintained onlyas long as a store of creatine phosphate lasts. 
according t o Bendall (1951), Iawrie (1953), and Bate-Smith (1956), the 
dephosphorylation increasingly exceeds rephosphorylation so that the 
actual ATP level itself begins t o fall , whether glycolytic resynthesis is 
proceeding o r not. 
i n amounts equivalent t o t h e amounts of ATP t h a t disappear. 
suggested the following chain of reactions as shown on Slide 11. 
Beyond t h i s point, 
A t this stage, ammonia and inosine monophosphate appear 
Bate-Smith has 
111. 
Slide I 
0.4 
0.1 
0 
Time (min. in nitrogen a t 37' C . ) 
'7 - 0 I ATP;/\-& CP; 0-0, pH; 8-e extens ib i l i ty (R. A. Uwrie, J. Physiol. 1953 (121), 275-288) 
112 
Slide I1 
ATP - 9 ADP +. P (mPase) 
__1___7) ATP 4 AMP (qyokinase) 
AMP 3 IMP + % (deaminase) 
Ammonia is l iberated from the deamination of AMP t o inosine mono- 
In phosphate as ske le ta l muscle passes in to r igor mortis, (Webster, 1953). 
fac t , i n a recent publication by Dvorak on "Breakdown of Adenine Nucleotides 
i n Beef Muscle Post-Mortem" the author stated that as ATP i s a c r i t e r ion f o r 
beginning of r igor mortis i n muscle it may a lso be said that the production 
of ammonia from nucleotides terminates at the beginning of r igor mortis. 
Physical Changes During Rigor Mortis: 
As indicated at the beginning of t h i s report, physical changes 
occur simultaneously with changes in the chemical constituents. One of the 
observable changes is the change i n muscle appearance. 
Marsh (1953) reported three types of whale mat, "dry," "wet" and 
rubbery." Through several experiments he has shown that these three types 
of m s c l e are manifestations of different phases of the onset and resolution 
of r igor mortis. 
meat i s meat which has passed throu& r igor and the "rubbery" meat is meat 
i n the stage of rigor. Marsh, f i r ther found tha t as l a c t i c acid was formed 
it was accompanied by a sizeable decrease i n f luid retention and a relat ive- 
l y rapid t rans i t ion t o a state of wetness. 
reported by Ingram (1955) t o occur i n horse muscle during r igor mortis. 
H 
The 'Id,, meat has not passed through rigor; the "wet" 
The same character is t ics were 
Shortening and Extensibil i ty: 
O t h e r physical phenomena are changes i n shortening and extensi- 
b i l i t y . A relationship exists (Marsh, 1953) between shortening and extensi- 
b i l i t y which indicates that fewer cross-bond l inks are present with increased 
shortening. This suggests that individual bonds become available during the 
onset of r igor f o r e i t h e r s h o r t e n i q o r an increase i n resistance t o exten- 
sion which gives fu r the r support t o the cross-linked s t ructure suggested by 
Bate-Smith. A continued study reported by Marsh i n 1957 held still a 
further explanation of this shortening phenomenon. He suggested tha t at 
50$ shortening the e l a s t i c l i m i t of a containing membrane i s reached and 
fur ther shortening is possible only a f t e r ruptures of the sarcolemma occur. 
pH Changes During Rigor Mortis: 
The change i n the pH of the musculature during r igor mortis is of 
multiple importance as previous speakers have indicated. 
Initial pH - It has been shown by Bate-Smith, Bendall, Iawrie and 
Marsh that the i n i t i a l and ultimate pH values of the muscle are c r i t i c a l i n 
determining the time course of rigor, and therefore, the fac tors which 
113 . 
predetermine these pH values are of the greatest importance, 
t o t h e factors determining the i n i t i a l pH has been provided by the Universi- 
t y of Cambridge workers through the use of myanesin. Through the use of 
t h i s material it was possible t o study animals paralyzed and fully Elaxed 
and provided what has been termed as a standard muscle. 
several of t h e i r experiments with t h i s drug suggested that the i n i t i a l pH 
is determined mainly by the severity of the death struggle. 
The main clue 
The resu l t s of 
U1timat.e pH - The two factors of greatest importance i n determin- 
ing the ultimate pH appear t o be the leve l of feeding and degree of fatigue 
before death. This has been demonstrated in rabbits by Bate-Smith and 
Bendall, beef by Lawrie and Howard, swine by Iudvigsen, Mackintosh, J. Wismer-Pedersen and the Wisconsin workers. 
was not correlated with the ultimate pH. 
In all cases the i n i t i a l pH 
These factors have been mentioned in this report since the con- 
d i t ion of the animals musculature is highly related t o the chemical and 
physical changes during rigor mortis. 
It has been reported by several workers (Eate-Smith, Lawrie, 
Ludvigsen and the Wisconsin wrkers ) that muscles contain a variable &mount 
of glycogen. Arring normal anaerobic glycolysis, glycogen is converted t o 
l a c t i c acid or possibly other acid components which measurably reduce pH. 
The severity of t h i s reduction, however, depends on the buffering power of 
the muscle. Bate-Smith has shown tha t the buffering power of rabbit muscle 
is about 50 m. eq./100 g. of muscle per pH unit. This means that the pro- 
duction of 15 l a c t i c acid will usually cause a s h i f t of about 1.8 pH units. 
As has been stated previously, it has been clear ly demonstrated by the 
Canibridge workers (Bate-Smith, Bendall, Uwrie and Marsh) t ha t the onset of 
r igor in rabbit muscle is dependent, not on pH, but on the ATP content; 
nevertheless, a t any given ultimste pH, the ATP content a t commencement of 
r igor is approximately constant, and, in noma1 rigor, acid production and 
ATP decomposition run paral le l . 
Slide I11 -- The next slide was taken f r o m a table published by 
Marsh (1954). "Rigor Mortis i n Beef Muscle". This s l ide also shows the 
close relationship between a decrease i n pH and Xl!P content. A s t h e pH 
drops from 6.60 t o about 5.40 there is a concomitant decrease i n ATP from 
about 20 t o approximately 3. 
114. 
Slide I11 
The Relationship Between pH and ATP content 
pH range ATP-P as $I of T.S.P. (man * standard deviation) 
above 6.60 20.5 f1 .5 
6.59 - 6.40 19 9 2.5 
6.39 - 6.20 16 2 2.5 
6.19 - 6.00 
5.99 - 5.68 
13 2.5 
+ 5.79 - 5.60 5 - 2.5 
5.59 - 5.40 3 - 1.5 9 
Part of Table I11 (B. B. Marsh, J. Sci. Food and Agr. 5, 1954) 
Thus a knowledge of the pH a t m y time allows an estimate of the 
progress of t h e onset of r igor , 
decrease i n the water-binding properties of the muscles. 
reported, however, that only one-third of the drop in hydration during 
post-mortem ciianging is explained by the drop i n pH. 
two-thirds of the loss of hydration is due t o the loss of ATP and t h a t this 
decrease i n hydration i s proportional t o the decrease i n ATP. 
breakdown of ATP i t s bound cations are released because AMP and IMP have a 
much lower a b i l i t y t o form complexes. 
corporated in to the protein structure causing a t igh te r network of a lower 
hydration. 
contain l e s s bound magnesium than those of the r igor o r post-rigor muscle. 
With t h i s drop i n pH there is a concomitant 
Hcumn (1959) has 
Hamm suggests that 
By the 
The cations thus released can be in- 
In fac t , the proteins of beef muscle immediately after slaughter 
Tissue Death - It has been suggested tha t the accumulation of 
l a c t i c acid proceeds with increased velocity when a par t icu lar pH i s reached. 
Apparently synchronizing with t h i s phase (Rowan, 1940) a f a l l occurs i n 
e l e c t r i c a l resistance and reactance. According t o Hemingway and Collins 
(1932), these changes are due t o the v i r t u a l elimination of membrane re- 
sistance and capacitance. It is att h i s stage that the muscle presumably 
loses i t s abi l i ty t o contract when stimulated, and the free difYusion of 
ions through the previously impemable membranes resu l t s i n a rapid 
equalization of pH throughout the t i s sue with possible exceptions, however, 
i n pork muscle. 
of the muscle. 
ishing ra te u n t i l e i t h e r glycogen i s exhausted o r a second fixed point i n 
pH is reached at which the glycolytic enzyme s y s t e m i s inhibited. 
According to Bate-Smith t h i s is the true point of "death" 
From t h i s point onward, glycolysis continues at a dimin- 
Time - - The time f o r the completion of the onset of rigor will, of 
course, vary widely according t o several fac tors previously mentioned such 
115 e 
as cooler efficiency, i n i t i a l pH, temperature and ultimate pH. 
these works pertain t o rabbit, beef and horse muscle. 
a post-mortem si tuat ion i n pork involving an abnormally low pH. According 
t o Iawrie, t h i s might be due t o au abnormally high rate of breakdown of ATP. 
Inrdvigsen has found that during post-mortem chi l l ing the t issue becomes ex- 
tremely abnormal and appears t o be loosely bound. The Wisconsin workers 
have observed that it is the lowest pH which the t issue obtains rather than 
i t s ultimate pH which dictates color and wateriness. 
Most of 
We do, however, have 
Oxidation-Reduction - The last point which I wish t o cover on 
physical change is the change in the oxidation-reduction potent ia l reported 
by Bsrnes and Ingram (1955). 
f a l l i n Eh from positive t o negative values OCCUPG during the first stages 
of rigor, during the phase of creatine phosphate disappearance. 
They have shown very clear ly that the main 
Subsequent Ripening of Muscle Tissues: 
Most of the reported work of muscle ripening per ta ins primarily t o 
I w i l l hasten t o add that the present projects underway by Wilson and beef. 
Schweigert of the American Meat Ins t i t u t e on "High Temperature Aging" and 
"Enzymes Concerned with Aging" as well as chemical aspects of tenderization 
by Deatherage w i l l undoubtedly mark major contributions t o t h i s area of 
knowledge. 
moderate degree f o r the past 30 years, Moran and Smith (1929) put forward 
the view that the connective tissue was the major element contributing t o 
tenderness and therefore was the component most l i k e l y t o be subject t o 
change during ripening. The theory of t o t a l connective t i s sue was ref'uted 
by Wilson and B r a y and temporarily lended fu r the r support t o Steiner's 
(1939) interpretation that as ripening proceeds the increase i n tenderness 
i s due exclusively t o an ef fec t upon the muscle fibers. 
The area of ripening snd tenderization has been studied t o a 
Among the proteins of the f ibers are a considerable number which 
Those remaining ac- 
function as enzymes, but most of these w i l l have been deprived of the i r 
natural substrates by changes occurring during rigor. 
t i ve are concerned with the breakdown of protein o r autolysis. 
enzyme i n t h i s regard is s t i l l thought t o be cathepsin, although current re- 
search may present a new outlook i n this regard. 
followed by an increase i n nonprotein nitrogen and an increase i n sulfhydryl 
groups. 
proteins. 
naturation as such should cause meat t o become more tender, since it w i l l be more drastically coagulated when cooked. 
The primary 
This autolysis could be 
These changes may be interpreted as 8 sign of denaturation of the 
According t o Bates-Smith, there is no apparent reason why de- 
In general, the ac t iv i ty of cathepsin increases with a decrease of 
pH (Bradley, 1938) but several workers (Smorodintsev and Nikolaeva, 1936, 
1942) found that in ripening muscle the catheptic ac t iv i ty actually decreased 
40-45$ i n the first 24 hours post-mortem and 20$ fur ther during the next 5 
days storage at 32-40° F. 
Prudent (1947) and Winegarden (1952) reported tha t there are no 
post-mortem changes i n connective t issue. Wierbicki, e t al., (1954) also 
s ta ted that connective t i s sue does not appear t o contribute t o increases i n 
tenderness on post mortem aging inasmuch as t o t a l alkali insoluble protein 
116 
does not challge. It was also shown by Ramsbottom and Strandine (1949) that 
beef taken immediately at slaughter and before the onset of r igor was more 
tender than beef during r igor mortis. The Ohio workers (Wierbicki, I&znkle, 
Cahi l l and Deatherage) have reported that the changes in muscle plasma are 
d i r ec t ly associated with tenderness. 
creases i n tenderness with post mort;em age may be related t o the redis- 
t r ibu t ion of ions within the muscle, thus causing increased hydration and 
tenderness. I n 1956 through the use of improved techniques it was shown by 
these workers that the toughening of meat associated with the onset of r igor 
mortis is due t o the formation of actomyosin; however t h e actomyosin is not 
dissociated in to ac t in and myosin on post mortem aging and thus i s not re- 
sponsible f o r post mortem tenderization. - e t ,', a1 (1956) that post morten tenderization may be related t o changes i n 
the protein systems of muscle in such a way as t o cause increased hydration. 
A similar study by Arnold, Wierbicki and Deatherage held as a basic premise 
t h a t proteins and ions i n f'unctioning muscle are apparently in a high s t a t e 
of organization and that af ter the onset of r igor mortis it is possible 
that there is a random diffusion and redistribution of ions. 
t ha t the ionic s h i f t s might be related t o the degree of hydration of the 
muscle protein and thereby related t o tenderness, since it is known tha t 
the degree of hydration is related t o tenderness. 
They reported i n 1954 tha t the in- 
It was a lso suggested by Wierbicki, 
It was thought 
Results of the experiment showed that f o r each carcass, without 
exception, sodium and calcium were released by the meat proteins and 
potassium was absorbed during post-mortem aging. 
t o t a l cationic sh i f t was a movement of ions in to the meat proteins. This 
was due t o the large amount of potassium ions taken up i n re la t ion t o the 
amount of sodium and calcium released. The r e su l t of t h i s movement of ions 
was that the tusc le proteins became more posi t ively charged. 
calcium was a lso thought t o be responsible t o some extent f o r the increase 
of hydration of the actomyosin complex. 
increased charge on the meat proteins allowing grea te r hydration and improved 
tenderness. 
In SUmmElry: 
For the most part the 
The release of 
The en t i r e e f f e c t resulted i n an 
1. 
2. 
3. 
4. 
The most obvious physical change occurring during the onset of 
r igor mortis o r s t i f fen ing is an increase i n the modulus of 
elasticity accompanied by a shortening of the f ibers . 
There are actual ly two phases of rigor: 
during which the modulus of e l a s t i c i t y changes only slightly 
and (b) a "rapid phwe" in which it increases rapidly t o i t s 
maximum which may be 10-40 time6 greater than the i n i t i a l 
value. 
(a) a "delay period" 
The creatine phosphate l eve l is high immediately post-mortem, 
but decreases rapidly thereaf te r and is reduced t o less than 
205 of i t s i n i t i a l l eve l before there is any appreciable 
loss O f ATP. 
The disappearance of ATP, once s tar ted, proceeds at a steady 
rate u n t i l less than 308 of the rest ing amount remains. 
117 
5. 
6. 
7. 
8 . 
9. 
10. 
1. 
2. 
3. 
4. 
During the "delay period'' the breakdown of ATP is exactly 
balanced by its resynthesis fromthe glycolyt;ic cycle and 
creatine phosphate. 
reserve of glycogen i n the muscle is almost exhausted, 
The rapid phase of r igor occurs when the 
During glycolysis, l a c t i c acid is produced presumably i n 
amounts regulated by the i n i t i a l glycogen concentration. 
Ammonia i s a l so l iberated f romthe deamination of AMP t o IMP 
as skeletal muscle passes in to r igor mortis. 
conferred on dead muscle is actual ly due t o actomyosin which 
i n the absence of ATP is extended and fim, 
The r ig id i ty 
The i n i t i a l pH of the musculature i s apparently determined 
mainly by the severi ty of the death s tmggle, while the 
ultimate pH is a ref lect ion of the l eve l of feeding and de- 
gree of fa t igue before death. 
The severi ty of pH reduction is governed somewhat by the 
buffering pover of the muscle and i n turn regulates t o some 
extent the change i n hydration o r water-binding. 
suggested recently, however, that only one-third of the drop 
in hydration i s explained by the change i n pH whereas two- 
th i rds of the lo s s of hydration is due t o the loss of ATP. 
Simultaneous with this change is a f a l l in e l e c t r i c a l re- 
sistance and reactance which is seemingly due t o the elimina- 
t i o n of membrane resistance. 
It has been 
The primary enzyme concerned with the breakdown of protein is 
st i l l thought t o be cathepsin. 
The latest information on ripening supports the contention 
that during post-mortem aging there is a redis t r ibut ion of 
ions within the muscle which causes increased hydration and 
consequently increased tenderness, 
BIBLIOGRAPHY 
Arnold, N., Wierbicki, E., and Deatherage F, E., 1956. Food 
Tech. Champaign 10 : 245. 
Astbury, W. T., 1942. X-rays and the Stoichiometry of t h e 
Proteins, with Special Reference t o the Structure of the 
Keratin-myosin Group. J. Chem. SOC. 1942, 337. 
Bailey, K., 1942. Myosin and Adenosinetriphosphatase. 
Biochem. J. 36, 121. 
Bailey, K. and B, B. Marsh, 1952. The Effects of Sulphydryl 
Biochem. e t Reagents on Glycolysis i n Wscle Homogenates. 
Biophys. Acta. 9, 133 
118 . 
5. 
6. 
7. 
8. 
9. 
10. 
11. 
12. 
13. 
14. 
15. 
16 a 
17 . 
18. 
Banfield, F. H., 1935. The Electrical Resistance of Pork and 
Bacon. Jb SOC. Chem. Ind. 54, 411T. 
Barnes, Ella M. and M. Ingram, 1955. Changes in the Oxidation - Reduction Potential of the Sterno-Cephalicus Wscle of the 
Horse After Death in Relation to the Development of Bacteria. 
J. Sci. Food Agric. 6, 1955. p. 448. 
Bate-Smith, E. C., 1948. Observations on the pH and Related 
Properties of Meat. J. Soc. Chem. Ind. 67, 83. 
Bate-Smith, E. C. and J. R. Bendall, 1947. Rigor Mortis and 
Adenosinetriphosphate. J. physiol., 106, 177. 
€!ate-Smith, E. C. and J. R. Bendall, 1956. 
After Death. 
Changes in Mscle 
British Medical Bul. l2, 3, 230, 
Bate-Smith, E. C,, 1939. Changes in Elasticity of Me3wnalian 
Muscle Undergoing Rigor Nmtis. J. of Physiology Vol. 96, No. 2, p. 176. 
Bate-Smith, E. C., and J. R. Bendall, 1949. Factors Deter- J. Physiol. 110, mining the Time Course of Rigor Mortis. 
47-65, 
Bate-Smith, E, C., 1936. The Wfect of Fatigue on Post-mortem 
Changes in mscle. Dept. Sci. Ind. Res, Ann. Rept. Food 
Invest. Bd. (Brit.) p,21. 
Bate-Smith, E. C., 1938a. The Buffering of Muscle in Rigor: 
Protein, phosphate and Carnosine. J. Physiol. (London) 92, 336. 
Bate-Smith, E. C., 1938b. Physiology of Rigor Mortis. Dept. 
Sci. Ind. Res. Ann, Rept. Food Invest. Bd. (Brit.) p. 15. 
Bate-Smith, E. C., 1948. The Physiology and Chemistry of 
Rigor Mortis, with Special Reference to the Aging of Beef. 
AdV. Food FkS. Vole 1, 
bte-Smith, E. C., 1933. Physiology of Muscle Protein. Ann. 
Rept. Food Invest. Bod., p. 19. 
Bate-Smith, E. C., 1937, Native and Denatured Muscle Pro- 
teins. Proc. Roy. Soc. London Bl24, 136. 
Bendall, J. R., 1953. Further Observations on a Factor (The- 
"March-Factor") Effecting Relaxation of ATP - Shortened 
Muscle - Fibre Models, and the Effect of Ca and Mg ions 
upon it. Journ. of Phys. Vol. 121, Mo. 2, 232. 
119 . 
19 . 
20. 
21 . 
22. 
23. 
24. 
25 . 
26 . 
27. 
28 
29 
30, 
31 
Bendall, J, R., 1951. The Shortening of Rabbit Mscles k r - 
in@; Rigor Mortis: Adenosine Triphosphate and Creatine Phosphate and t o 
Muscular Contraction. Journ. of physiology Vol. 114, No. 1 
80 2, p. 71. 
Its Relation t o the Breakdown of 
Bendall, J. R. and C. L. Davey, 1957. Ammonia Liberation 
During Rigor Mortis and I t s Relation t o Changes i n the 
Adenine and Inosine Nucleotides of rabbit Muscle. Bio- 
chimica e t Blophysica Acta. Vol. 26 93. 
Bouton, P. E., A. Howard and R. A, Uwrie, 1957. Studies on Beef Quality. Part VI. EOfects on Weight Losses and 
Eating Quality of lhrtkr Pre-slaughter Treatments. Food 
I n V . Spec. Repto NO. 66. 
Bouton, P. E., A. Howard and R. A. Uwrie, 1958. Studies on Beef Quality. part V I I . The Influence of Certain Holding 
Conditions on Weight Losses and Eating Quality of Fresh and 
Frozen Beef Carcasses. Spec. Rept. No. 67. Food Inv. Bd. 
Bradley, H. C., 1938. Autolysis and Atrophy. Physiol. Revs. 18, 173, 
Brisbey, E. J., R. W. Bray, W. G. Hoekstra, P. H. Phi l l ips 
and R. H. Grummer, 1959. The Effect of Exhaustive mer- 
cise and High Sucrose Regimen on Certain Chemical and 
Physical Pork Barn M e c h Characteristics. 
18, 1, 173. 
J. Animal Sci. 
Callow, E. B., 1935. 
Callow, E. H. Rep. Food Invest. Bd., 31 (1939) Iudvigsen, J., 
Carcass a a l i t y of the Pig i n Relation 
t o Growth and Met. 
262 ber f ra f ors#gslaboratoret (Copenhagen) 1954 . 
Esnp. Journ. Exp. Agric. 2, 80, 
Callow, E. H., 1937. The ' ' U l t i m a t e pH" of Wscular Tissue. 
Dept. Sci. Ind. Res. Ann. Fkpt. Food Inv. Bd. (Brit.), 
pa 48. 
Cater, D. B. and Phill ips, A. F., Naturce, Lond., 1954, 174, 
121. 
Deatherage, F. E. and A. Harsh, 1951. Tenderization of 
Meat. U. S. Patent 2,544,681. 
Deatherage, F. E. and A. Harsham, 1947. Relation of Tender- Food Research 12, ness of Beef to Aging Time at 33-35' F. 
164-172. 
Deatherage, F. E. and W. Relman, 1946. 
Tenderness and Tenderization of Beef by the Tenderay 
Process. Food &search 11, 525-534. 
Measurement of Beef 
120 . 
32. Deatherage, F. E., 1956. Food Tech, Champaign 10:80 
33. Depocas, Florent, 1959. The Pool Size, Turnover Rate, and 
Oxidation Rate of Body Glucose i n Anesthetized Warm-and 
Cold-Acclimated Rats Rcposed t o a Warm Environment. 
Canadian Jour. of Biochemistry and Physiology, Vol. 37, NO, 2, p. 285. 
34. Deuticke, H. J., 1930. Changes i n the Colloidal Nature of 
m s c l e Proteins in Death and Fatigue. Arch. Ges. 
Physiol, (PflQgerts) 224, 1. 
35. Dvorak, Z., 1958. B1.eakdown of Adenine Nucleotides in Beef 
Nuscle Post Mortem and i ts Relation t o the Content of 
Ammonia. Experientia VOL XIV / 4, p b 133. 
36. Embden, G., and Habs, H., 1927. Chemical and Biological 
Changes of the msculature after Frequently Repeated 
Faradic Stimulation. Z. Physiol. Chem. 171, 16. 
37 . Engel' hardt , V . A., 1946. Adenosinetriphosphatase properties 
of wosin. Advances i n Enzymol. 6, 147. 
38. Engel'hardt, V, A., Ljubimova, M. N., and Meitina, R. A., 
Chemistry and Mechctnics of the Nuscle Studied on 1941. 
bbosin Threads. Compt. rend. acad. sci. W.R.S.S. 30, 644. 
39. Engel'hardt, W. A. and Ljubimova, M. N., 1939. Nature, 
Lnndon 144,669, 
40. Erd8s, T., 1943. Stud. Inst. Med. Chem. Univ. of Szeged, 
3,51 
41. Hall, J. L., Utschar, E. E., and Mackintosh, D. L., 1944. 
Characteristics of Dark-Cutting Beef. 
liminary Investigation. 
Bul. 58, F'art N. 
Survey and Pre- Kansas Agr. Expe. Sta., Tech. 
42. Ramm, Reiner, 1959, Biochemistry of Meat Hydration. 11th 
Annual Res.Cod. of American Meat Ins t i tu te Foundation. 
43. Hemingway, A., and Collins, D. A,, 1932, High and Low 
Frequency E l e c t r i c d Resistance Changes i n Dying Voluntary 
Nuscle of Rabbits. Am. J. Physiol. 99, 338. 
44, Henry, M., Romani, J. D., and Joubent, L., 1958. Rev. Path. 
Gen. Phys. Clin,, No. 696, 355. 
45. H i l l , A. V., 1938. Proc. Roy. Soc. B, 124, 114. 
46. Hoet, J. P. and Marks, H, P., 1926. Proc. Roy. Soc. B, 100, 
72 . 
121 . 
47. 
48. 
49. 
50 . 
51 
52 . 
53. 
54. 
55. 
56 . 
57 . 
58. 
59 . 
60 
61 . 
Hoagland, R., McBryde, C. N., and Powiclr, W. C., 1917. 
Changes in Fresh k e f W i n g Cold Storage Above Freezing. 
U. S. Dept. of Agr. &la 433. 
Roward, A. and R. A. Zawrie, 1956. Part; 11. Physiological 
and Biochemical Effects of Various Pre-Slaughter Treatments. 
Food Inv. Spec. Rept. No. 63. 
Howard, A. and R. A. fawrie, 1957. Further Observations on 
Biochemical and Physiological Responses t o Pre-Slaughter 
Treatments. Food Inv. Spec. Rept. No. 65. 
Husaini, S. A., Deatherage, F. E., I,. E. Khnkle and H. N. 
Draudt, 1950. Studies on Meat I. Biochemistry of Beef as 
Related t o Tenderness. Nod Tech., 4, 313-316. 
Husaini, S. A., Deathemge, F. E., L. E. mnkle, 1950. 
Studies on Meat 11. 
a c t o r s t o Changes i n Tenderness. 
Observation on Relation of Biochemical 
Food Tech., 4, 366-369. 
Ingram, M. and G. C. Ingreun, 1955. The Gmwth of Bacteria on 
Horse Muscle i n Relation t o the Changes After Death Leading 
t o Rigor Mortis. J. Sci. Food and Agric. 6, p. 602. 
Jokl, E., 133. The Carbohydrate Exchange During mscular 
Exercise i n the Warm-Blooded Organism. Arch. ges. Physiol. 
( d g e r t s ) 232, 687. 
Untersuchungen Gber das Protoplasm und die 
Contractili-&t . Engelmann, k i p z i g . Kbne, W., 1864. 
Lawrie, R. A. Some Observations on Factors Affecting Myoglo- 
bin Concentrations i n Wscle. Journ. of Agric. Sci. Vol. 
40, Part 4. 
Lswrle, R, A. J. Agric. Sci., 1950. 40 356. 
Iawrie, R. A., 1953. Effect of Enforced Exercise on 
Myoglobin Concentration i n Muscle. Nature, Vol. 171, p. 
1069 
Iawrie, R. A., 1953. The Onset of Rigor Mortis i n Various 
Wscles of the Draught Horse. Journ. of Physiology, Vol. 
121, No. 2, p. 275. 
Lawrie, R. A., 1955. Fksidual Glycogen at High Ultimate pH 
i n Horse Muscle. 
Lawr-ie, R. A., 1953. The Relation of Energy-rich Phosphate 
i n Vuscle t o l@’oglobln and t o Cytochrome-oxidase Activity. 
Biochem. Journ., Vol. 55, N0.2 p. 305. 
Lawrie, R. A,, Biochem. J. 1953. 55, 305. 
122 . 
62. Lawrie, R. A,, 1958. Physiological Stress i n Relat ion t o 
Dark-Cutting Beef. J. Sci. Food Agric. - 9, 11, 721. 
63. Lawrie, R. A,, 1958. Abnormally Low Ultimate pH in Pig 
Muscle. Nature, Vol. 182, pp. 807-808. 
64. Lundsgaard, E,, 1930b. Studies on Muscle Contraction Without 
Lactic acid Production. Biochem. 2, 217, 162. 
65. Iwdsgaard, E., 1931, The Energetics of Anaerobic Muscle 
Contraction. Biochem. Z. 233, 322. 
66, Mackintosh, J, A o j SOtOh, J e BOmS, M. Ma Robe?ASj J . j 
Prouty, C. C. and Ensluinger, Ma E., 1942. The Relation of 
Ultra-violet LQht and Temperature During Aging of Quality 
Beef. Wash. Agr. Expt. Sta. Bul, 422, 26. 
67, bbdsen, J. 1943-44. Investigations on the Keeping Quality 
of Pork from Animals which have been Fed Feed Containing 
Sugar. 
Centr., 1944 , I, 1939) Nord. Jordbnagsforskning 1943, 5-6, 340 (Chem. 
68. Marsh, B. B o j 1954. Rigor Mortis i n Beef. J. Sci. Food 
69. Marsh, B. B., 1952. The effects of ATP on the Fibre Volume 
Agric. - 5, 70, 
of a M~~scle Homogenate. Biochim. Biophys. A c t a . 9, 247, 
70. Marsh, B, B.3 1958. Rigor Mortis and Thaw Rigor in Lamb. J. Sci. Food Agric., 2, 417. 
71. Marsh, B. B. and J. F. Thompson, 1957. Thaw Rigor and the 
Delta State of Muscle. Biochim. Biopliis. Acta. e 24, 427. 
72. Marsh, B. B., 1952. Observations on Rigor Mortis i n Whale 
Wscle. Biochem e t Biophys. Acta. 9, 127. 
73. Marsh, B. B . j 1953. Shortening and Ektensibility i n Rigor 
Mortis. Biochem e t Biophys. Acta. l2, 478. 
74. McCarthy, J. F., and King, C. G a j 1942, Chemical Changes 
Accompanying Tenderization of Beef. Food Research 7, 295. 
75. Moran, T., 1935. Post-Mortem and Refrigeration Changes in 
Meat. J. SOC. Chem. Ind. 54, 14s. 
76. Moran, T., and Smith, E. C., 1929, Post-Mortem Changes in 
Animal Tissues. 
Dept. Sci. Ind. Res. Food Invest. Board (Brit.) Spec. 
Rept. No, 36. 
The Conditioning o r Ripening of Beef. 
77. b r a n , To, and Smith, E. C., 1929, Post-Mortem Changes i n 
Animal Tissues. 
Food Invest. Bd. Special Rept. No. 36, H. M. Stationery 
Office, London. 
The Conditioning o r Ripening of Beef. 
123 
78. 
79. 
80. 
81 
82 
83. 
84. 
85 
86 
87 
88 
89 . 
90 . 
91. 
Needham, D. El., 1942 . The Adenosinetriphosphatase Activity 
of Myosin Preparations. Biochem. J. 36, 113. 
Ogilvy, W. S. and Ayres, J. C., 195la. Post-Mortem Changes 
i n Stored Mats. 11. The Effect of Atmospheres Containing 
Carbon Dioxide in Prolonging the Storage Life of Cut-up 
Chicken. Food Tech. 5, 97. 
Perry, S. V., 1951. The Adenosinetriphosphatase Activity of 
W o f i l b r i l s Isolated from Skeletal Nuscle. Biochem. J. 48, 
257-265 . 
Perry, S. V., 1950. Studies on the Rigor Resulting f r o m the 
Thawing of Frozen Frog Sartorius Muscle, J. Gen. Physiol. 
33, 563. 
Procter, H. A., and Best, C. H., 1932. Changes i n Muscle 
Glycogen Accmpanying Physical Training. Am. J. Physiol. 
100, 506. 
Prudent, Inez, 1947. The Collagen and Elast in Content of 
Four Beef Ebscles Aged Varying Periods of Time. 
Dissertation, Iowa State College, Ames, Iowa. Ph.D. 
Ramsbottom and Strandine, (1949). I n i t i a l Physical and 
Chemical Changes i n Beef as Related t o Tenderness. J, 
Animsl SCi. 8, 398, 410. 
Rowan, A. N., 1940, The Elec t r ica l Resistance of Muscle. 
Dissertation, Uhiv. of Cambridge (Abstr. Index L i t . Food 
Invest. 13, 4, 1942), 
Ronzoni, E., 1931. Phosphate Changes i n Chloroform Rigor 
with and without Production of Lactic Acid. Pmc. Soc. 
Expt. Bioi. &de 28, 712, 
Sair, L., and Cook, W. H., 1938. Relation of pH t o Drip 
Rnxnation i n Meat. Canad. J. Research 16D, 225. 
Schoon, J. G., and Ooms, A., 1933. Acidity of Muscle in Normal and Diseased Animals. Tijdschr. Mergeneesk. 
60, 393. 
Sharp, J. G., 1935. Post-Mortem Breakdown of Glycogen and 
Accwnulation of Iactic Acid i n Fish N s c l e a t Low Temper- 
atures. Biochem. J. - 29, 850. 
Sharp, J. G. and G. Howard Smith, 1952. The Changes 
Occurring in Whale Meat During Storage i n the Frozen 
State. J. Sci. Food and Agric. 2, 4, 379. 
Sharp, J. G. and B. B, Marsh, 1953. Whalemeat: Production 
and Preservation. Food Lnvestigation. Sp. Rept. No. 58, 
pa 12. 
124. 
92. 3caife, J. F., 1955. Variation of U l t i m a t e pH within Pig 
Muscles. J. Sci. Food and Agric. 6, August, 1955. p. 467. 
93. Smorodentser, I. A. and Nikolaeva, N. V., 1936. Modification 
of Cathepsin Curing Autolysis of Wscular Tissue. 
rend. acad. sc i . U.S.S.R., N. S,, 3, 375. Compt. 
94. Steiner, G. 193%. The Post-Modern Changes i n Beef m s c l e at 
Various Temperatures. Arch. Hyg. 121, 193. 
95. Schipiloff, C., 1882. Zbl, med. Wiss. 20, 291. 
96. Szent-Gybrgyi, A., 1945. Acta. Physiol. Scand. 9, Suppl. 
No. 25. 
97. von dir th , O., 1919. The Colloid Chemistry of Bbscle and Its 
Relation t o Contraction and Rigor. Ergeb. Physiol. 1 7 , 363. 
98. Webster, H. L., 1953. The Deamination and Dephosphorylation 
of Adenine Nucleotides i n Wscle. 
degree, Univ. of Cambridge) . (Dissertation Ph.D. 
99. Wierbicpd, E., L. E. Kunkle, Cahill, V. R. and Deatherage, F. E., 1954. Relation of Tenderness t o Protein Alterations 
During Post ElorternAging. Food Tech. 8:506. 
100. Wierbicki, E., L. E. Kunkle and F. E. Deatherage, 1957. 
Changes i n the Water-Holding Capacity and Cationic Shifts 
During the Heating, Freezing and Thawing of Meat as 
Revealed by a Simple Centrifugal Method f o r Measuring 
Shrinkage. Food Tech. 11:69. 
101. Wierbicki, E,, and F. E. Batherage, 1954. J. Agric. Food 
Chem. 2:875. 
102. Winegarden, M. W., B. Lowe, 3. Kastelic, E. A. Kline, A, R, 
Plage and P. S. Shearer, 1952. Physical Changes of Con- 
nective Tissue of Beef During Heating. Food Res. 17, 172- 
84 . 
103. Vismer-Pederson, J., 1959, Some Obsenrations on the Quality 
of Cured Bacon i n Relation t o Ante-Nortem Treatment I - 111. 
Acta. Agr, Scand. IX, 1-69. 
MR, PEARSON: Thank you, Ernie. I see our time is up. Our Chair- 
man has informed me we can hold forth a while longer, so we are going ahead 
with our panel discussion at t h i s time. Originally I asked Dr, J. L. Hall, 
t o handle the Panel discussion, but due t o his health, he was unable t o at- 
tend t h i s year, and he asked I take o v e r t h i s par t icu lar part; of the pro- 
gram. We have four d i f fe ren t people on our panel this afternoon, Joe 
Kastelic, University of I l l i no i s ; our f r iend h a t h e m e , you have heard 
once; Hans Lillevfk, Michigan State University; Dr. Lil levik has been in- 
terested i n many problems i n proteins during the past winter, and he has had 
much t o do with the handling of t h i s subject. 
Am.e~Lcan Ins t i t u t e Foundation. 
four o r f ive minutes t o point out sone applications they can see from our 
di6CUSSiOn tNs afternoon. 1'11 cal l on Joe first. 
Then, we have D. M. Doty, 
I am going t o ask each of these men t o take