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Methods of Aging and Muscle Flexing and Their Effects upon the Tenderness of Turkey Meat1
193
AVAILABILITY OF SOYBEAN O I L
availability to the chick of the oil in unextracted soybeans. ACKNOWLEDGMENT These studies were supported in p a r t by the National Soybean Processors Association, Chicago, Illinois. REFERENCES Carew, L. B., Jr., 1961. Studies of the effects of dietary vegetable oils on growth rate, energy intake, tissue composition and energy metabolism of chicks. Doctorate Thesis, Cornell University. Carew, L. B., Jr., F. W. Hill and M. C. Nesheim, 1961. The comparative value of heated ground
unextracted soybeans and heated dehulled soybean flakes as a source of soybean oil and energy for the chick. J. Am. Oil Chemists Soc. 38: 249253. Carew, L. B., Jr., and M. C. Nesheim, 1962. The effect of pelleting on the nutritional value of ground soybeans for the chick. Poultry Sci. 41: 161-168. Dam, R., R. M. Leach, T. S. Nelson, L. C. Norris and F. W. Hill, 1959. Studies of the effect of quantity and type of fat on chick growth. J. Nutrition, 68: 615-632. Renner, R., and F. W. Hill, 1960. Studies of the effect of heat treatment on the metabolizable energy value of soybeans and extracted soybean flakes for the chick. J. Nutrition, 70: 219-225.
Methods of Aging and Muscle Flexing and Their Effects upon the Tenderness of Turkey Meat1 T. L. G O O D W I N , W.
C. M I C K E L B E R R Y AND W. J.
STADELMAN
Purdue University, Lafayette, Indiana (Received for publication April 3, 1961)
" D E C E N T L Y several devices and pro-"•^-cedures have been introduced which modify ice slush chilling. With the introduction of each new piece of equipment, m a n y questions arise as to the effect on rate of chilling, percentage water u p t a k e , and consumer acceptability. M a n y factors contribute to the relative tenderness or lack of tenderness of t u r k e y meat. Present evidence indicates t h a t aging is the factor contributing most to the tenderness value. The rate of aging can be modified b y ante-mortem treatment, killing procedure, and cooling procedure. Tenderness is a rate process (Klose et al., 1959; Pool et al., 1959) and the rate of tenderization is definitely controlled by certain biochemical reactions (deFremery 1 Journal Paper No. 1726 of the Purdue Agricultural Experiment Station, Lafayette, Indiana.
and Pool, 1960). T h u s , it is of value to determine the effect of rate of mechanical cooling and muscle flexing on the tenderness of the final product. The purpose of this research was to ascertain whether or not there were a n y changes in development of tenderness as the result of four different methods of cooling turkeys.
EXPERIMENTAL METHODS AND MATERIALS Sixty fourteen-week-old Beltsville torn turkeys were used in the experiment. All birds used were 7 | to 8§ pounds live weight. Turkeys were slaughtered b y slashing the throat and were allowed to bleed for 90 seconds prior to scalding for 55 seconds at 140°F. Feathers were removed b y a free floating picker during a 50 second picking cycle. T h e turkeys were immediately eviscerated with a minimum
194
T. L. GOODWIN, W. C. MICKELBERRY AND W. J. STADELMAN
cut around the vent so that the skin around the thighs was not disturbed. Necks were removed by slitting the skin on the back side, severing the muscles and twisting the neck free, leaving the skin attached to the body with an opening at the junction of the neck and body. The turkeys were then washed, drained for one minute, and the warm eviscerated weight recorded. The time for processing was 6 to 8 minutes. After weighing, the turkeys were immediately subjected to one of the following four cooling treatments: (a) tap water at 56°F., (b) slush ice water with no agitation, (c) slush ice water with agitation supplied by a submersible pump, and (d) a revolving wire basket suspended and revolved in a slush ice bath. The legs were not tucked so that legs and wings were free for flexing during the tumbling. Cooling curves were determined on three birds for each cooling procedure using a Minneapolis-Honeywell recording potentiometer model 143X10-V-II-III4. A single thermocouple was placed in the left side of the breast at a depth of 1 | inches in the pectoralis superficialis, If "to the right of the sternum and 2" to the rear of the furkula. This was securely anchored in place with twine and the turkey placed in its respective cooling treatment. Turkeys used in determination of the rate of cooling were not used in the evaluation for shear. These turkeys were allowed to remain in their respective treatments until the temperature of the breast was cooled to approximately the same temperature as the cooling medium. The turkeys remained in treatments b, c, and d for 2 hours. Immediately after chilling, the birds were allowed to drain for one minute and then weighed to determine the water uptake resulting from each cooling procedure. Those to be held longer were then placed in polyethylene bags and held in a refrigerated walk-in cooler
(34°F.) for the remainder of the aging time. The birds were weighed again immediately prior to cooking to determine the amount of water taken up during chilling which remained after 2, 6, 14, and 30 hours of draining time. The turkeys in tap water (treatment a) were held in the 56°F. water during the entire aging peroid. Aging times used were 2, 4, 8, 16, and 32 hours measured from the time the turkeys were placed in the cooling treatment. Before cooking, the wings were removed for use elsewhere and the weight of the wingless bird recorded. The turkeys were wrapped in a single thickness of 0.0015 inch aluminum foil and cooked in a 325°F. reel oven to an end temperature of 185°F., as measured one inch deep in the breast muscles. After cooking, the turkeys were cooled 24 hours in a 40°F. refrigerator and weighed to determine cooking and cooling loss. Following this, two 3 mm. slices, to a total depth of 6 mm., were removed from the external side of each pectoralis superficialis and the biceps femoris was removed from each thigh. A sample was obtained from each of these using the core cutting device developed by Dodge and Stadelman (1960). Shear was measured using a Kramer shear press. The birds on the tap water treatment (treatment a) were placed in a chill tank 48" X35"X32" of continuously flowing tap water. Turkeys chilled by slush ice (treatment b) were placed in a chill tank 30"X16"X17" and the tank filled with slush ice. The second means of agitation was obtained by placing the turkeys in a 30" X16"X17" chill tank with a submersible pump placed at one end (treatment c). The flow of water caused the birds to tumble while they were being chilled. A wire cage 31 inches by 32 inches with
195
TENDERNESS OF MEAT
the ends constructed of f inch plywood was suspended lengthwise into a 48"X35" X32" chilling tank. A 1J" pipe axle was extended through the center of the wire cage and securely clamped. A 12" V belt pulley was securely attached to one end of the axle. The cage was connected to a one H.P. electric motor through a series of reduction pulleys and rotated at approximately 13 RPM in the chill tank filled with ice and water (treatment d).
chilling. These two treatments resulted in a lower temperature and faster cooling than did tap water or slush ice. The average shear values necessary for the different muscles are listed in Table 1. When the data summarized in Table 1 were subjected to an analysis of variance (Table 2) no significant treatment effect was found. When the treatment effect was divided into the effect contributed by each method of chilling, it was of interest to note that differences in shear value between the rotary chill and the agitated slush ice approached significance at the 5 percent level. When considering the cooling time, only the linear effect was significant. The differences among parts (Layeri, Layer2 and thigh) were statistically significant (P<.05). The highly significant
RESULTS AND DISCUSSION
The rates of cooling during the first two hours post-mortem for the four treatments are shown in Figure 1. The agitated slush ice by submersible pump (treatment c) and the rotary chill wire cage (treatment d) resulted in nearly equal rates of 120,
60
50
40
Time (minutes) 30
x
20
s. \ .
\ Slush
Agitated > £ - 0 \ Slush Ice
"^ ~^
'"
Rotary Chill
30
40
50
60
70
Tap Water
80
90
100
Temperature (Degrees F)
FIG. 1. Rate of cooling, temperature in °F., average values for 3 turkeys for each curve.
110
196
T. L. GOODWIN, W. C. MICKELBERRY AND W. J. STADELMAN
variation between replications suggests that some as yet unidentified factors are exerting an important effect on shear value. The significant interaction of cooling method X part and the highly significant interaction of cooling method X cooling time X part indicates that the cooling method is having a statistical effect on the shear value of the different parts. All interactions which contain variance contributed by replication were highly significant. This suggests that the unidentified factors are exerting their effects throughout the analysis. In Table 2 the figures in parenthesis in " F observed" column are values needed for 5 percent level of significance; in the df column, they are the approximate degrees of freedom, (Satterthwaite, 1946) for calculated mean square error term used to determine significance of these sources of variance. The appropriate interaction was used to test the main effects. The flexing of the wings and legs by tumbling during chilling resulted in a TABLE 1.—Mean shear force for each method of chilling at each aging time for three cuts of turkey meat {averages of 3 turkeys) Cooling method aging times (hours)
Tap water
Slush ice
Agitated Rotary slush chill
Outer 3 mm. layer of pectoralis superficialis 2 38.2 33.7 35.0 44.9 4 35.8 31.3 28.7 45.6 8 28.1 15.3 24.9 39.9 16 33.3 20.3 27.7 29.0 32 21.8 19.1 24.6 36.7 Inner Layer of pectoralis superficialis—3-61mm. deep 2 28.7 38.5 34.6 47.9 4 26.7 17.1 26.7 58.7 8 11.2 8.0 21.8 33.1 16 21.2 8.2 17.2 15.9 32 13.1 15.5 14.8 37.3 2 4 8 16 32
"Biceps femoris (thigh) 69.6 57.8 43.6 53.3 42.9 43.4 44.4 29.5 42.9 39.4 28.7 33.8 35.3 22.3 22.9
56.6 37.9 37.4 37.7 23.0
TABLE 2.—Outline of analysis of variance of data summarized in Table 1 Source
Df
Total 359 Cooling Method 3 Tap Water vs Ice Slush Ice vs Agitation Rotary Chill vs Sump Pump 4 Cooling Time Linear Residual 2 Parts 2 Replication 12 CMXCT Linear Residual 6 CMXP 6 CMXR 8 CTXP Linear Residual 8 CTXR 4 PXR 24 CM X CTXP Linear Residual 24 CMXCTXR 12 CMXPXR 16 CTXPXR 48 CMXCTXPXR 180 Residual
(12) 1 1
1
(13) 1 3 (7) 3 9
2 6
6 18
MS
F observed
711.76 79.97 943.04
3.96(4.75)
1,112.29 1,276.46 4,668.70 148.71 1,905.13 304.76 69.29 42.37 78.26 265.18 147.65 96.98 237.87 53.20 373.61 166.72 50.78 10.30 64.28 106.44 86.26 62.01 23.29 28.27
2.99
—
4.67(4.75) 2.63 9.62*
— 8.33* 10.78** — — — 3.07*
5.22** 1.56 3.84
— 13.22** 5.89** 1.79* — 2.27 3.76** 3.05** 2.19** —
" Significant at the 0.05 level of probability. ** Significant at the 0.01 level of probability.
retarding of the development of maximum tenderness, but did not significantly affect tenderness after a maximum aging time of 32 hours. Klose el al. (1960) observed that tumbling friers in slush ice had no important effect on the rate of tenderization during the short chilling periods used. One possible explanation for the toughening effect due to the tumbling action may be greater loss of adenosinetriphosphate. The flexing action during tumbling may cause a faster and greater loss of adenosinetriphosphate. With the increased loss of A.T.P., more actomyosin may be formed causing the muscle fibers to have a greater density. This increase in density would require greater shear force, thus indicating the muscle was tougher. Table 3 lists the percentage of water uptake immediately after chilling and then after draining. Rotary chill caused a considerable increase in the percentage of water uptake as compared with the other treatments. The values listed are considerably above previously reported water
197
TENDERNESS OF MEAT TABLE 3.—Mean percentage of water uptake for four methods of cooling (averages of 3 turkeys')
Method
Time in coolant (hours)
% gain of warm evis. wt. after chilling
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
2 2 2 2
5.8 8.6 37.3 8.5
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
4 2 2 2
7.2 5.8 31.6 7.5
2 2 2
3.5 16.6 3.2
19.2 15.4 26.6 15.9
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
8 2 2 2
8.5 6.3 35.1 11.4
6 6 6
1.7 9.0 4.9
21.6 18.6 25.3 25.0
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
16 2 2 2
8.2 6.1 38.9 8.0
14 14 14
2.2 7.7 4.1
19.5 17.4 22.6 21.5
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
32 2 2 2
13.3 4.5 35.5 9.5
30 30 30
1.0 11.9 2.9
23.4 16.4 21.0 18.5
Time drained
%gain warm evis. wt. after draining
% cooking loss* 24.6 17.5 31.8 19.3
Cooking loss calculated as percent of oven-ready weight.
absorption figures. The rapid loss indicates little or no chemical binding of the water. Most of the water uptake by turkeys in the rotary chill birds appeared to be merely trapped in areas under the skin. However, when one observes the percentage of water retained after 30 hours of draining, the rotary chill turkeys retained more water than any of the other treatments. This could indicate that with the great increase in water uptake some of this water may be bound to the protein or lipid in some manner. The cooked yield and the percentage cooking loss was determined in all cases. The weight loss was correlated with water uptake and retention after a drain period. The r value calculated was +0.59. The yield of cooked weight of birds based on percentage of fresh eviscerated weight was comparable for all cooling treatments. This is in general agreement with Klose
et al. (1960) and Bailey et al. (1948) who stated that final cooked yield as expressed as percentage of original eviscerated weight did not differ appreciably between ice-slush-chilled and air-chilled birds. SUMMARY Studies conducted on fryer-roaster turkeys cooled by four methods indicate that rapid cooling is not a solution to the search for a more rapid method of tenderization of turkey meat. The flexing of the wings and legs by tumbling during chilling resulted in a retarding of the development of maximum tenderness, but had no significant effect when the turkeys were aged the maximum time of 32 hours. The turkeys subjected to the rotary chill method of chilling had a greater percentage of water Uptake and retained more of the water after 32 hours than did the other treatments. Yield of cooked
198
T. L. GOODWIN, W. C. MICKELBERRY AND W. J. STADELMAN
weight was not appreciably affected by chilling procedure. The birds which had gained considerable weight during chilling had considerably higher shrinkage during cooking. ACKNOWLEDGEMENT This work was supported in part by a grant from the National Turkey Federation. Appreciation for this support is expressed. REFERENCES Bailey, R. L., G. F. Stewart and B. Lowe, 1948. Ice slush cooling of dressed poultry. Refrigerating Engineering, 55: 369-371. Dodge, J. W., and W. J. Stadelman, 1960. Studies on tenderness evaluation. Poultry Sci. 39: 184187.
deFremery, D., and F. Pool, 1960. Biochemistry of chicken muscle as related to rigor mortis and tenderization. Food Research, 25: 73-87. Klose, A. A., M. F. Pool, M. B. Wiele, H. L. Hanson and H. Lineweaver, 1959. Poultry tenderness I. Influence of processing on tenderness of turkeys. Food Technol. 13: 20-24. Klose, A. A., M. F. Pool, D. deFremery, A. A. Campbell and H. L. Hanson, 1960. Effect of laboratory scale agitated chilling of poultry on quality. Poultry Sci. 39: 1193-1198. Pool, M. F., D. deFremery, A. A. Campbell and A. A. Klose, 1959. Poultry tenderness II. Influence of processing on tenderness of chickens. Food Technol. 13: 25-29. Satterthwaite, F. E., 1946. An approximate distribution of estimates of variance components. Biometrics Bulletin of the Biometrics Section of the American Statistician Association, 2: 110— 114.
Sulfanilamide, Specific Gravity of Eggs and an Interaction 1 WALTER A. BECKER 2 AND GORDON E. BEARSE Washington State University, Western Washington Experiment Station, Puyallup (Received for publication April 3, 1961)
T
HE average thickness of the egg shell is reduced when sulfanilamide is added to a laying hen's diet (Scott et al., 1945). Because of this fact, it might be argued that it would be desirable to select for egg shell thickness under the adverse condition of having sulfanilamide in the feed. The rationale would be that a breeder would be selecting hens that would lay eggs with thick shells under adverse conditions, as well as under more favorable conditions. However, one has to guard against the possibility that the "best" hens selected for thick egg shell under the sulfanilamide regime might not have the thickest egg 1 Scientific Paper No. 2094, Washington Agricultural Experiment Station, Pullman. Project 1274. 2 Present Address: Washington State University, Pullman.
shells when fed a normal diet. An interaction effect, hens X diets, would indicate that such a condition exists. This paper describes some effects of adding sulfanilamide to the diet and presents evidence for an interaction effect involving the specific gravity of eggs. METHODS AND RESULTS Four hundred, 11-month-old, White Leghorn pullets derived from a flockmated F 2 generation of a three-way cross were housed at random in pens of 200 birds each. The all-mash ration shown in Table 1 was fed to one pen, while the treated pen received the same ration plus 0.03 percent sulfanilamide. Individual egg production was measured on a five-day week basis for four weeks, using trapnests. The following
AVAILABILITY OF SOYBEAN O I L
availability to the chick of the oil in unextracted soybeans. ACKNOWLEDGMENT These studies were supported in p a r t by the National Soybean Processors Association, Chicago, Illinois. REFERENCES Carew, L. B., Jr., 1961. Studies of the effects of dietary vegetable oils on growth rate, energy intake, tissue composition and energy metabolism of chicks. Doctorate Thesis, Cornell University. Carew, L. B., Jr., F. W. Hill and M. C. Nesheim, 1961. The comparative value of heated ground
unextracted soybeans and heated dehulled soybean flakes as a source of soybean oil and energy for the chick. J. Am. Oil Chemists Soc. 38: 249253. Carew, L. B., Jr., and M. C. Nesheim, 1962. The effect of pelleting on the nutritional value of ground soybeans for the chick. Poultry Sci. 41: 161-168. Dam, R., R. M. Leach, T. S. Nelson, L. C. Norris and F. W. Hill, 1959. Studies of the effect of quantity and type of fat on chick growth. J. Nutrition, 68: 615-632. Renner, R., and F. W. Hill, 1960. Studies of the effect of heat treatment on the metabolizable energy value of soybeans and extracted soybean flakes for the chick. J. Nutrition, 70: 219-225.
Methods of Aging and Muscle Flexing and Their Effects upon the Tenderness of Turkey Meat1 T. L. G O O D W I N , W.
C. M I C K E L B E R R Y AND W. J.
STADELMAN
Purdue University, Lafayette, Indiana (Received for publication April 3, 1961)
" D E C E N T L Y several devices and pro-"•^-cedures have been introduced which modify ice slush chilling. With the introduction of each new piece of equipment, m a n y questions arise as to the effect on rate of chilling, percentage water u p t a k e , and consumer acceptability. M a n y factors contribute to the relative tenderness or lack of tenderness of t u r k e y meat. Present evidence indicates t h a t aging is the factor contributing most to the tenderness value. The rate of aging can be modified b y ante-mortem treatment, killing procedure, and cooling procedure. Tenderness is a rate process (Klose et al., 1959; Pool et al., 1959) and the rate of tenderization is definitely controlled by certain biochemical reactions (deFremery 1 Journal Paper No. 1726 of the Purdue Agricultural Experiment Station, Lafayette, Indiana.
and Pool, 1960). T h u s , it is of value to determine the effect of rate of mechanical cooling and muscle flexing on the tenderness of the final product. The purpose of this research was to ascertain whether or not there were a n y changes in development of tenderness as the result of four different methods of cooling turkeys.
EXPERIMENTAL METHODS AND MATERIALS Sixty fourteen-week-old Beltsville torn turkeys were used in the experiment. All birds used were 7 | to 8§ pounds live weight. Turkeys were slaughtered b y slashing the throat and were allowed to bleed for 90 seconds prior to scalding for 55 seconds at 140°F. Feathers were removed b y a free floating picker during a 50 second picking cycle. T h e turkeys were immediately eviscerated with a minimum
194
T. L. GOODWIN, W. C. MICKELBERRY AND W. J. STADELMAN
cut around the vent so that the skin around the thighs was not disturbed. Necks were removed by slitting the skin on the back side, severing the muscles and twisting the neck free, leaving the skin attached to the body with an opening at the junction of the neck and body. The turkeys were then washed, drained for one minute, and the warm eviscerated weight recorded. The time for processing was 6 to 8 minutes. After weighing, the turkeys were immediately subjected to one of the following four cooling treatments: (a) tap water at 56°F., (b) slush ice water with no agitation, (c) slush ice water with agitation supplied by a submersible pump, and (d) a revolving wire basket suspended and revolved in a slush ice bath. The legs were not tucked so that legs and wings were free for flexing during the tumbling. Cooling curves were determined on three birds for each cooling procedure using a Minneapolis-Honeywell recording potentiometer model 143X10-V-II-III4. A single thermocouple was placed in the left side of the breast at a depth of 1 | inches in the pectoralis superficialis, If "to the right of the sternum and 2" to the rear of the furkula. This was securely anchored in place with twine and the turkey placed in its respective cooling treatment. Turkeys used in determination of the rate of cooling were not used in the evaluation for shear. These turkeys were allowed to remain in their respective treatments until the temperature of the breast was cooled to approximately the same temperature as the cooling medium. The turkeys remained in treatments b, c, and d for 2 hours. Immediately after chilling, the birds were allowed to drain for one minute and then weighed to determine the water uptake resulting from each cooling procedure. Those to be held longer were then placed in polyethylene bags and held in a refrigerated walk-in cooler
(34°F.) for the remainder of the aging time. The birds were weighed again immediately prior to cooking to determine the amount of water taken up during chilling which remained after 2, 6, 14, and 30 hours of draining time. The turkeys in tap water (treatment a) were held in the 56°F. water during the entire aging peroid. Aging times used were 2, 4, 8, 16, and 32 hours measured from the time the turkeys were placed in the cooling treatment. Before cooking, the wings were removed for use elsewhere and the weight of the wingless bird recorded. The turkeys were wrapped in a single thickness of 0.0015 inch aluminum foil and cooked in a 325°F. reel oven to an end temperature of 185°F., as measured one inch deep in the breast muscles. After cooking, the turkeys were cooled 24 hours in a 40°F. refrigerator and weighed to determine cooking and cooling loss. Following this, two 3 mm. slices, to a total depth of 6 mm., were removed from the external side of each pectoralis superficialis and the biceps femoris was removed from each thigh. A sample was obtained from each of these using the core cutting device developed by Dodge and Stadelman (1960). Shear was measured using a Kramer shear press. The birds on the tap water treatment (treatment a) were placed in a chill tank 48" X35"X32" of continuously flowing tap water. Turkeys chilled by slush ice (treatment b) were placed in a chill tank 30"X16"X17" and the tank filled with slush ice. The second means of agitation was obtained by placing the turkeys in a 30" X16"X17" chill tank with a submersible pump placed at one end (treatment c). The flow of water caused the birds to tumble while they were being chilled. A wire cage 31 inches by 32 inches with
195
TENDERNESS OF MEAT
the ends constructed of f inch plywood was suspended lengthwise into a 48"X35" X32" chilling tank. A 1J" pipe axle was extended through the center of the wire cage and securely clamped. A 12" V belt pulley was securely attached to one end of the axle. The cage was connected to a one H.P. electric motor through a series of reduction pulleys and rotated at approximately 13 RPM in the chill tank filled with ice and water (treatment d).
chilling. These two treatments resulted in a lower temperature and faster cooling than did tap water or slush ice. The average shear values necessary for the different muscles are listed in Table 1. When the data summarized in Table 1 were subjected to an analysis of variance (Table 2) no significant treatment effect was found. When the treatment effect was divided into the effect contributed by each method of chilling, it was of interest to note that differences in shear value between the rotary chill and the agitated slush ice approached significance at the 5 percent level. When considering the cooling time, only the linear effect was significant. The differences among parts (Layeri, Layer2 and thigh) were statistically significant (P<.05). The highly significant
RESULTS AND DISCUSSION
The rates of cooling during the first two hours post-mortem for the four treatments are shown in Figure 1. The agitated slush ice by submersible pump (treatment c) and the rotary chill wire cage (treatment d) resulted in nearly equal rates of 120,
60
50
40
Time (minutes) 30
x
20
s. \ .
\ Slush
Agitated > £ - 0 \ Slush Ice
"^ ~^
'"
Rotary Chill
30
40
50
60
70
Tap Water
80
90
100
Temperature (Degrees F)
FIG. 1. Rate of cooling, temperature in °F., average values for 3 turkeys for each curve.
110
196
T. L. GOODWIN, W. C. MICKELBERRY AND W. J. STADELMAN
variation between replications suggests that some as yet unidentified factors are exerting an important effect on shear value. The significant interaction of cooling method X part and the highly significant interaction of cooling method X cooling time X part indicates that the cooling method is having a statistical effect on the shear value of the different parts. All interactions which contain variance contributed by replication were highly significant. This suggests that the unidentified factors are exerting their effects throughout the analysis. In Table 2 the figures in parenthesis in " F observed" column are values needed for 5 percent level of significance; in the df column, they are the approximate degrees of freedom, (Satterthwaite, 1946) for calculated mean square error term used to determine significance of these sources of variance. The appropriate interaction was used to test the main effects. The flexing of the wings and legs by tumbling during chilling resulted in a TABLE 1.—Mean shear force for each method of chilling at each aging time for three cuts of turkey meat {averages of 3 turkeys) Cooling method aging times (hours)
Tap water
Slush ice
Agitated Rotary slush chill
Outer 3 mm. layer of pectoralis superficialis 2 38.2 33.7 35.0 44.9 4 35.8 31.3 28.7 45.6 8 28.1 15.3 24.9 39.9 16 33.3 20.3 27.7 29.0 32 21.8 19.1 24.6 36.7 Inner Layer of pectoralis superficialis—3-61mm. deep 2 28.7 38.5 34.6 47.9 4 26.7 17.1 26.7 58.7 8 11.2 8.0 21.8 33.1 16 21.2 8.2 17.2 15.9 32 13.1 15.5 14.8 37.3 2 4 8 16 32
"Biceps femoris (thigh) 69.6 57.8 43.6 53.3 42.9 43.4 44.4 29.5 42.9 39.4 28.7 33.8 35.3 22.3 22.9
56.6 37.9 37.4 37.7 23.0
TABLE 2.—Outline of analysis of variance of data summarized in Table 1 Source
Df
Total 359 Cooling Method 3 Tap Water vs Ice Slush Ice vs Agitation Rotary Chill vs Sump Pump 4 Cooling Time Linear Residual 2 Parts 2 Replication 12 CMXCT Linear Residual 6 CMXP 6 CMXR 8 CTXP Linear Residual 8 CTXR 4 PXR 24 CM X CTXP Linear Residual 24 CMXCTXR 12 CMXPXR 16 CTXPXR 48 CMXCTXPXR 180 Residual
(12) 1 1
1
(13) 1 3 (7) 3 9
2 6
6 18
MS
F observed
711.76 79.97 943.04
3.96(4.75)
1,112.29 1,276.46 4,668.70 148.71 1,905.13 304.76 69.29 42.37 78.26 265.18 147.65 96.98 237.87 53.20 373.61 166.72 50.78 10.30 64.28 106.44 86.26 62.01 23.29 28.27
2.99
—
4.67(4.75) 2.63 9.62*
— 8.33* 10.78** — — — 3.07*
5.22** 1.56 3.84
— 13.22** 5.89** 1.79* — 2.27 3.76** 3.05** 2.19** —
" Significant at the 0.05 level of probability. ** Significant at the 0.01 level of probability.
retarding of the development of maximum tenderness, but did not significantly affect tenderness after a maximum aging time of 32 hours. Klose el al. (1960) observed that tumbling friers in slush ice had no important effect on the rate of tenderization during the short chilling periods used. One possible explanation for the toughening effect due to the tumbling action may be greater loss of adenosinetriphosphate. The flexing action during tumbling may cause a faster and greater loss of adenosinetriphosphate. With the increased loss of A.T.P., more actomyosin may be formed causing the muscle fibers to have a greater density. This increase in density would require greater shear force, thus indicating the muscle was tougher. Table 3 lists the percentage of water uptake immediately after chilling and then after draining. Rotary chill caused a considerable increase in the percentage of water uptake as compared with the other treatments. The values listed are considerably above previously reported water
197
TENDERNESS OF MEAT TABLE 3.—Mean percentage of water uptake for four methods of cooling (averages of 3 turkeys')
Method
Time in coolant (hours)
% gain of warm evis. wt. after chilling
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
2 2 2 2
5.8 8.6 37.3 8.5
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
4 2 2 2
7.2 5.8 31.6 7.5
2 2 2
3.5 16.6 3.2
19.2 15.4 26.6 15.9
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
8 2 2 2
8.5 6.3 35.1 11.4
6 6 6
1.7 9.0 4.9
21.6 18.6 25.3 25.0
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
16 2 2 2
8.2 6.1 38.9 8.0
14 14 14
2.2 7.7 4.1
19.5 17.4 22.6 21.5
Tap Water Slush Ice Rotary Chill Slush Ice with Agitation
32 2 2 2
13.3 4.5 35.5 9.5
30 30 30
1.0 11.9 2.9
23.4 16.4 21.0 18.5
Time drained
%gain warm evis. wt. after draining
% cooking loss* 24.6 17.5 31.8 19.3
Cooking loss calculated as percent of oven-ready weight.
absorption figures. The rapid loss indicates little or no chemical binding of the water. Most of the water uptake by turkeys in the rotary chill birds appeared to be merely trapped in areas under the skin. However, when one observes the percentage of water retained after 30 hours of draining, the rotary chill turkeys retained more water than any of the other treatments. This could indicate that with the great increase in water uptake some of this water may be bound to the protein or lipid in some manner. The cooked yield and the percentage cooking loss was determined in all cases. The weight loss was correlated with water uptake and retention after a drain period. The r value calculated was +0.59. The yield of cooked weight of birds based on percentage of fresh eviscerated weight was comparable for all cooling treatments. This is in general agreement with Klose
et al. (1960) and Bailey et al. (1948) who stated that final cooked yield as expressed as percentage of original eviscerated weight did not differ appreciably between ice-slush-chilled and air-chilled birds. SUMMARY Studies conducted on fryer-roaster turkeys cooled by four methods indicate that rapid cooling is not a solution to the search for a more rapid method of tenderization of turkey meat. The flexing of the wings and legs by tumbling during chilling resulted in a retarding of the development of maximum tenderness, but had no significant effect when the turkeys were aged the maximum time of 32 hours. The turkeys subjected to the rotary chill method of chilling had a greater percentage of water Uptake and retained more of the water after 32 hours than did the other treatments. Yield of cooked
198
T. L. GOODWIN, W. C. MICKELBERRY AND W. J. STADELMAN
weight was not appreciably affected by chilling procedure. The birds which had gained considerable weight during chilling had considerably higher shrinkage during cooking. ACKNOWLEDGEMENT This work was supported in part by a grant from the National Turkey Federation. Appreciation for this support is expressed. REFERENCES Bailey, R. L., G. F. Stewart and B. Lowe, 1948. Ice slush cooling of dressed poultry. Refrigerating Engineering, 55: 369-371. Dodge, J. W., and W. J. Stadelman, 1960. Studies on tenderness evaluation. Poultry Sci. 39: 184187.
deFremery, D., and F. Pool, 1960. Biochemistry of chicken muscle as related to rigor mortis and tenderization. Food Research, 25: 73-87. Klose, A. A., M. F. Pool, M. B. Wiele, H. L. Hanson and H. Lineweaver, 1959. Poultry tenderness I. Influence of processing on tenderness of turkeys. Food Technol. 13: 20-24. Klose, A. A., M. F. Pool, D. deFremery, A. A. Campbell and H. L. Hanson, 1960. Effect of laboratory scale agitated chilling of poultry on quality. Poultry Sci. 39: 1193-1198. Pool, M. F., D. deFremery, A. A. Campbell and A. A. Klose, 1959. Poultry tenderness II. Influence of processing on tenderness of chickens. Food Technol. 13: 25-29. Satterthwaite, F. E., 1946. An approximate distribution of estimates of variance components. Biometrics Bulletin of the Biometrics Section of the American Statistician Association, 2: 110— 114.
Sulfanilamide, Specific Gravity of Eggs and an Interaction 1 WALTER A. BECKER 2 AND GORDON E. BEARSE Washington State University, Western Washington Experiment Station, Puyallup (Received for publication April 3, 1961)
T
HE average thickness of the egg shell is reduced when sulfanilamide is added to a laying hen's diet (Scott et al., 1945). Because of this fact, it might be argued that it would be desirable to select for egg shell thickness under the adverse condition of having sulfanilamide in the feed. The rationale would be that a breeder would be selecting hens that would lay eggs with thick shells under adverse conditions, as well as under more favorable conditions. However, one has to guard against the possibility that the "best" hens selected for thick egg shell under the sulfanilamide regime might not have the thickest egg 1 Scientific Paper No. 2094, Washington Agricultural Experiment Station, Pullman. Project 1274. 2 Present Address: Washington State University, Pullman.
shells when fed a normal diet. An interaction effect, hens X diets, would indicate that such a condition exists. This paper describes some effects of adding sulfanilamide to the diet and presents evidence for an interaction effect involving the specific gravity of eggs. METHODS AND RESULTS Four hundred, 11-month-old, White Leghorn pullets derived from a flockmated F 2 generation of a three-way cross were housed at random in pens of 200 birds each. The all-mash ration shown in Table 1 was fed to one pen, while the treated pen received the same ration plus 0.03 percent sulfanilamide. Individual egg production was measured on a five-day week basis for four weeks, using trapnests. The following