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Yield of Turkey Parts in Relation to Turkey Roll Composition1
Yield of Turkey Parts in Relation to Turkey Roll Composition1 M. HAL TAYLOR2 AND JACK L. FEY 3 Kansas State University, Manhattan, Kansas 66504 (Received for publication July 14, 1966)
T
1 Contribution No. 629, Department of Poultry Science, Kansas Agricultural Experiment Station, Manhattan, Kansas 66504. 2 Poultry Science Department, University of Maryland, College Park, Maryland 20740. 'Poultry Science Department, University of Florida, Gainesville, Florida 32603.
of raw turkey roasts (U.S.D.A., 1964) does not specify exactly the natural proportions of turkey roasts, it does require that "products produced from more than one part be labeled as containing natural proportions of the named parts." The regulations also state that "only sufficient skin to completely wrap the product may be used, but there shall be no overlapping of the skin or that skin be used not in excess of 15 percent." Based on these points two experiments were conducted; the first to obtain further data on parts yield of ready-to-cook turkeys and to establish if there were differences in yield of parts between different strains. The second experiment was conducted to obtain information on the make-up of meat and skin in turkey rolls and to examine the limits for the amount of skin in turkey rolls made from natural proportions of whole ready-to-cook turkeys. MATERIAL AND METHODS
Turkeys for the first experiment of this study were selected from 12 strains entered and raised in the 1961 Kansas Central Random Sample Turkey Meat Production Test (U.S.D.A., 1961). Five males and five females were randomly selected from each strain. Hens 22 weeks of age and toms 26 weeks of age were commercially processed and chilled in slush-ice-water overnight, packaged in Cryovac bags, blast frozen at - 3 7 ° C . ( - 3 5 ° F . ) , and held at - 1 8 ° C . (0°F.) in public storage until used. The frozen turkeys were thawed in a walk-in cooler held 11.0-12.5°C. (52°-55°F.). After the hens were thawed for 28 hours and the toms for 48 hours, excess moisture
374
Downloaded from http://ps.oxfordjournals.org/ at University of Rhode Island on April 4, 2015
INTRODUCTION HE further processing of ready-tocook turkeys is rapidly expanding, resulting in the need for more specific information on the yield of parts. Since previous work has indicated that yield of parts may differ between strains, it is possible that processors may soon be selecting turkeys by strain for further processsing and whole bird merchandising. Another problem that exists in the further processing field is that roll composition is not definitely established. Therefore, formulae for predicting composition of turkey rolls of different sizes would be of considerable value to the industry as a whole. A review by Fry et al. (1962) indicated the wide variation in yield of parts reported in earlier papers was due to differences in procedure in cutting and in methods of calculating percentages. Fry et al. (1962) determined yield of parts from turkeys of different commercial strains and reported average breast yields of 32.5% for males and 30.8% for females. Thigh yields for males and females were 14.6% and 15.2%, respectively. However, these percentages were for boneless breast with skin, and thighs with skin and bone. Although Article 81.131 (c) of the government regulations governing the labeling
375
YIELD OF TURKEY PARTS
RESULTS AND DISCUSSION
The varieties and strains of turkeys utilized in the first study are presented in Table 1. The average absolute and relative
T A B L E 1.—Varieties and strains of turkeys test yield of parts Strain
no 1 3 5 7 9 11 12
*ggS
Strain
used to
E
88s
sampled b " * l n White sampled in * in Schmidt Kansas 2 Segars Kansas Kimber California 4 Wilford Kansas Nicholas strain Kansas 6 Keithly Kansas cross Meadowbrook Kentucky 8 Nicholas Kansas Browning Kansas 10 Wrolstad Kansas Rose-A-Linda Missouri — — — Waite's — — — Bronze
yields of the boneless breast, boneless thigh, and boneless skinless breasts and thighs are presented in Table 2. Average percentage yields of the other parts approximated those reported by Fry et al. (1962). The average percentages of yield between strains for boneless skinless breast ranged from 23.4 to 29.7 for the males, and from 22.8 to 28.9 for the females. Differences in percentage yields of breast indicated the amount of breast skin varied individually and by strains. The percentage for the skinless thighs ranged from 12.9 to 14.1 in the males, and from 13.3 to 14.8 in the females. This substantiates results published by Fry et al. (1962) showing that the average percentage of breast was highest in male turkeys and that females had a larger percentage of thigh meat. These data indicated that percent of skin on both breast and thighs was about the same for males and females. The mean weights of the skinless breasts and thighs of the males were 6.35 and 3.17 pounds, respectively, and for the females these values were 2.80 and 1.55 pounds. The percentages of the skinless breast and thigh of ready-to-cook turkey expressed as averages were 27.1 and 13.5 for the males and 25.4 and 14.2 for the females, respectively. Table 3. contains the analyses of variance of yield of skinless breast and thigh meat. The 12 strains differed significantly in both absolute and relative yields of skinless breast meat, while the skinless thigh yields did not differ in absolute weights.
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was wiped from the exteriors and body cavities before the birds were cut into parts. The method of cutting up the turkeys followed the suggestion of the NCM-7 meat yields bulletin (Swanson et al., 1964) with the following exeptions: (1) the neck was skinless, (2) the breast was boneless and skinless, and (3) thighs were deboned and skinless. Parts were weighed to the nearest one-hundredth of a pound as soon as they were detached from the carcass. The yield for each part was calculated as the percentage of the ready-to-cook carcass, minus giblets. Hereafter, all breast and thigh meat will be considered boneless, unless otherwise specified. The second experiment consisted of 124 commercial Grade A Bronze toms, weighing 22-24 lbs. ready-to-cook. They were processed, Cryovac packed and blast frozen at - 3 7 ° C . ( - 3 5 ° F . ) . These birds were also held at - 1 8 ° C . (0°F.) in public storage until they were cut-up. After thawing 36 to 42 hours at approximately 21°C. (70°F.), each bird was skinned and deboned. The deboned, skinless breasts and thighs were separately weighed to the nearest one-hundredth of a pound and the skin weight was determined by difference between the sum of the breast and thigh weights and the completed roll weight. The 124 rolls were prepared by placing the anterior ends of the left and right breasts on the skin parallel to each other but in opposite directions. The skinless thighs were placed on top of the breasts, the skin overlapped, and the rolls hand stitched. Each roll contained the entire boneless breast and thigh muscles of the whole ready-tocook turkey, and only enough skin was utilized to enclose them completely.
376
M. H. TAYLOR AND J. L. FRY TABLE 2.—Average yields of boneless breast and boneless thigi hs from male and female turkeys of twelve different strains Ev. Wt.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
Breast Lbs.
Breast
24.87 23.14 25.94 23.33 25.01 22.50 23.19 23.19 22.66 16.87 25.43 25.20
7.93 7.60 8.19 7.87 8.68 7.05 7.40 7.59 6.83 5.80 8.30 7.93
31.9 32.8 31.6 33.7 34.7 31.3 31.9 32.3 30.1 34.4 32.6 31.5
Ave.
23.44
7.60
32.4
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
11.15 10.67 11.84 10.85 11.53 11.19 11.29 11.04 11.24 7.75 12.38 10.91
3.22 2.99 3.42 3.41 3.47 3.26 3.20 3.20 3.13 2.26 3.78 3.01
29.1 28.0 28.9 31.4 30.1 29.1 28.3 29.0 27.9 29.2 30.5 27.6
Ave.
10.99
3.20
29.1
%
Skinless Breast Lbs.
Skinless Breast
%
Thighs Lbs.
%
Skinless Thighs Lbs.
Skinless Thighs
Thighs
%
Males (Toms) 26.6 6.61 27.9 6.46 27.3 7.07 29.4 6.98 29.7 7.42 26.9 6.05 24.8 5.76 26.9 6.23 23.4 5.30 28.8 4.85 27.8 7.07 25.3 6.38
3.85 3.35 3.98 3.50 3.71 3.45 3.56 3.43 3.56 2.54 3.91 3.85
15.5 14.5 15.3 15.0 14.8 15.3 15.4 14.8 15.7 15.1 15.4 15.3
3.34 2.98 3.63 3.16 3.18 3.14 3.11 3.27 3.02 2.29 3.48 3.40
13.4 12.9 13.6 13.3 12.9 14.0 13.4 14.1 13.3 13.6 13.8 13.5
27.1
3.56
15.2
3.17
13.5
Females (Hens) 2.54 22.8 2.59 24.3 2.93 24.8 3.00 27.7 2.98 25.9 2.83 25.5 2.92 25.9 2.78 25.2 2.76 24.2 2.01 25.9 3.58 28.9 2.62 24.0
1.78 1.73 1.84 1.69 1.86 1.78 1.82 1.78 1.76 1.23 1.95 1.71
16.0 16.2 15.5 15.6 16.1 15.9 16.1 16.1 15.7 15.9 15.8 15.7
1.65 1.58 1.57 1.48 1.64 1.37 1.59 1.57 1.60 1.10 1.83 1.60
14.8 14.5 13.3 13.6 14.2 14.3 13.8 14.2 14.2 14.2 14.8 14.3
1.74
15.9
1.55
14.2
6.35
2.80
There were highly significant differences between strains in relative weights (Table 4). The two sexes differed significantly in both absolute and relative weights of both kinds of meat. The interaction between strain and sex was significant in all analyses except that
25.4
of absolute thigh weights. Since in the other three instances this interaction was highly significant, it may be concluded that sex and strain interact in both absolute and relative weights of breast and thigh meat. The males were consistently heavier than the females in absolute weight of boneless,
TABLE 3.—Analyses of variance of yield of boneless, skinless breast and thigh meat
Source Between strains Between sexes Interaction Error Total
Thigh
Degrees of Freedom
Mean Squares
F Observed
Mean Squares
F Observed
11 1 11 96
2.66 378.53 .96 .11
24.18** 3,441.18** 8.73**
.60 73.59 .15 .34
1.76 216.44** .44
119
Significant at .01 level.
Breast
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Strain No.
377
YIELD OF TURKEY PARTS TABLE 4.—Analyses of variance of angles corresponding to percentages of boneless, skinless breast and thigh meat
Source
Thigh
Breast
Degrees of Freedom
Mean Squares
F Observed
11 1 11 96
10.61 34.15 2.99 0.60
17.68** 56.91** 4.98**
Between strains Between sexes Interaction Error
Mean Squares
F Observed
0.37 10.47 0.52 0.15
2.47** 69.80** 3.47**
119
Total
** Significant at .01 level.
(1) (2) (3) (4)
Yx = Y2 = Y3 = Y =
6.21 1.33 6.21 1.33
+ + + +
0.588 0.221 0.549 1.186
(x (x (x (x
-
10.26) 10.26) 10.26) 10.26)
where x, Yi, and Y2 were the weights in pounds of the roll, breast and skin, respectively, and where Y3 and Y4 were the angles corresponding to the percentage weights of breast and skin, respectively.
The regression coefficients for both breast and skin weights on roll weight were highly significant by t-test. A nonsignificant coefficient of regression was found for percentage breast weight on roll weight, but a significant coefficient was calculated in the case of percentage skin weights. Therefore, it seems feasible from a practical viewpoint to resort to the absolute rather than to the relative weights. Applying these regression equations it is possible to estimate the breast and skin component parts in a marketable turkey roll. From a practical viewpoint tables are more popular than equations; therefore, the fiducial limts of the byx's are presented in Table 5. for the absolute and relative skin and breast portions of the rolls. Accordingly, in Table 6 the fiducial limits for the absolute and relative skin and breast portions were estimated for the heaviest (11.29 lbs.) and the lightest (9.21 lbs.) roll weights in the sample studied. This esTABLE 5.—Fiducial limits for the coefficients of regression (byx)1 Dependent variable Y 1 Breast weight lbs. Angles corresponding to percent breast Skin weight lbs. Angles corresponding to percent skin l
X = roll weight in pounds.
Lower Level
Upper Level
0.493
0.683
-0.740 0.108
1.172 0.334
0.280
2.092
Downloaded from http://ps.oxfordjournals.org/ at University of Rhode Island on April 4, 2015
skinless breast meat (Table 2). Yet the highly significant interaction between sex and strain for this trait (Table 3) reflect a wide variation in its sex difference. For example, in strain Number 5 sex difference was almost twice as much as that of strain No. 9 (4.44 vs. 2.54 lbs., respectively). In the second experiment, 124 rolls were made from whole ready-to-cook torn turkeys (average weight 22.37 lbs.). Each roll comprised all of the skinless breast and thigh meat of the ready-to-cook turkey and only enough skin to enclose the meat. In each roll the absolute and relative weights of each kind of meat were established. Percentage values were converted to degrees of an angle for computing regression equations. The average weight of the rolls was 10.26 pounds, containing 60.50% of breast meat (6.21 lbs.), 26.60% of thigh meat (2.73 lbs.), and 12.90% of skin (1.33 lbs.). Regression equations for breast and skin weights on roll weights were established as follows:
378
M. H. TAYLOR AND J. L. FRY TABLE 6.-—Fiducial
limits for skin and breast meat in turkey rolls made from natural proportions of whole torn turkeys
Lightest roll (9.21 lbs.) Min. Av. Max. Skin weight lbs. Percent skin Breast weight lbs. Percent breast
.98 10.40 5.49 58.52
1.10 11.43 5.59 59.62
X = 10.26 + 0.846 (Yi - 6.21) + 0.667 (Y2 - 2.73), where Y2 and Y2 are the boneless, skinless breast and thigh weights in pounds, respectively. SUMMARY Two experiments were designed to determine the yield of various parts of ready-tocook turkeys, and to find the relationship of these parts to the composition of turkey rolls. In the first experiment 120 turkeys, five of each sex from 12 different strains were cut up and the absolute and relative weights of their different parts established. The mean weight of the boneless, skinless breasts and thighs of the males were 6.3S and 3.12 pounds, respectively. For the females these values were 2.80 and 1.56 pounds. These parts represented 27.1% and 13.2% of the whole ready-to-cook turkey for the males, and 25.4% and 14.2% for the females. In the second experiment, 124 rolls were made from 124 male turkeys. Each roll comprised all the boneless, skinless breast meat, thigh meat and the sufficient skin to completely enclose the roll. In each roll the absolute and relative weights of each kind
1.44 13.20 6.72 59.25
1.56 14.31 6.82 61.59
1.67 15.46 6.91 62.66
of meat were estimated. The average roll weight of 10.26 pounds contained 60.50% of breast meat (6.21 lbs.), 26.60% thigh meat (2.73 lbs.), and 12.98% of skin (1.33 lbs.). Regression equations for breast and skin weights on roll weights were established. It was thus possible to estimate each of these two components in marketable turkey rolls. Regression coefficients for both breast and skin weights on roll weights were highly significant, (byx = 0.588 and 0.221 lbs., respectively). An insignificant coefficient of regression (0.549%) was found for percentage breast weight on roll weight, but a significant coefficient was established in the case of percentage skin weight (byx = 1.186%). These estimates provide adequate market specifications for composition of turkey rolls which are of interest to both processors and consumers. REFERENCES Fry, J. L., O. S. Rao and L. D. Rasplicka, 1962. Factors affecting the yield of turkey parts. Poultry Sci. 4 1 : 1299-1303. Swanson, M. H., C. W. Carlson and J. L. Fry, 1964. Factors affecting poultry meat yields. North Central Regional Research Publication No. 158. Station Bulletin 476, University of Minnesota. U.S. Department of Agriculture, 1961. Turkey performance tests, 1961. Agricultural Research Service, U.S.D.A., ARS. U.S. Department of Agriculture, 1964. Poultry Inspector's Handbook, 1964. Agriculture Marketing Service, Poultry Division, U.S.D.A., AMS.
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tablished ranges for the amount of breast, thigh and skin in turkey rolls. The following multiple regression equation combines both breast (Yi), and thigh (Y2) meat in the prediction of roll weight (X):
1.22 12.48 5.69 60.75
Heaviest roll (11.29 lbs.) Min. Av. Max.
T
1 Contribution No. 629, Department of Poultry Science, Kansas Agricultural Experiment Station, Manhattan, Kansas 66504. 2 Poultry Science Department, University of Maryland, College Park, Maryland 20740. 'Poultry Science Department, University of Florida, Gainesville, Florida 32603.
of raw turkey roasts (U.S.D.A., 1964) does not specify exactly the natural proportions of turkey roasts, it does require that "products produced from more than one part be labeled as containing natural proportions of the named parts." The regulations also state that "only sufficient skin to completely wrap the product may be used, but there shall be no overlapping of the skin or that skin be used not in excess of 15 percent." Based on these points two experiments were conducted; the first to obtain further data on parts yield of ready-to-cook turkeys and to establish if there were differences in yield of parts between different strains. The second experiment was conducted to obtain information on the make-up of meat and skin in turkey rolls and to examine the limits for the amount of skin in turkey rolls made from natural proportions of whole ready-to-cook turkeys. MATERIAL AND METHODS
Turkeys for the first experiment of this study were selected from 12 strains entered and raised in the 1961 Kansas Central Random Sample Turkey Meat Production Test (U.S.D.A., 1961). Five males and five females were randomly selected from each strain. Hens 22 weeks of age and toms 26 weeks of age were commercially processed and chilled in slush-ice-water overnight, packaged in Cryovac bags, blast frozen at - 3 7 ° C . ( - 3 5 ° F . ) , and held at - 1 8 ° C . (0°F.) in public storage until used. The frozen turkeys were thawed in a walk-in cooler held 11.0-12.5°C. (52°-55°F.). After the hens were thawed for 28 hours and the toms for 48 hours, excess moisture
374
Downloaded from http://ps.oxfordjournals.org/ at University of Rhode Island on April 4, 2015
INTRODUCTION HE further processing of ready-tocook turkeys is rapidly expanding, resulting in the need for more specific information on the yield of parts. Since previous work has indicated that yield of parts may differ between strains, it is possible that processors may soon be selecting turkeys by strain for further processsing and whole bird merchandising. Another problem that exists in the further processing field is that roll composition is not definitely established. Therefore, formulae for predicting composition of turkey rolls of different sizes would be of considerable value to the industry as a whole. A review by Fry et al. (1962) indicated the wide variation in yield of parts reported in earlier papers was due to differences in procedure in cutting and in methods of calculating percentages. Fry et al. (1962) determined yield of parts from turkeys of different commercial strains and reported average breast yields of 32.5% for males and 30.8% for females. Thigh yields for males and females were 14.6% and 15.2%, respectively. However, these percentages were for boneless breast with skin, and thighs with skin and bone. Although Article 81.131 (c) of the government regulations governing the labeling
375
YIELD OF TURKEY PARTS
RESULTS AND DISCUSSION
The varieties and strains of turkeys utilized in the first study are presented in Table 1. The average absolute and relative
T A B L E 1.—Varieties and strains of turkeys test yield of parts Strain
no 1 3 5 7 9 11 12
*ggS
Strain
used to
E
88s
sampled b " * l n White sampled in * in Schmidt Kansas 2 Segars Kansas Kimber California 4 Wilford Kansas Nicholas strain Kansas 6 Keithly Kansas cross Meadowbrook Kentucky 8 Nicholas Kansas Browning Kansas 10 Wrolstad Kansas Rose-A-Linda Missouri — — — Waite's — — — Bronze
yields of the boneless breast, boneless thigh, and boneless skinless breasts and thighs are presented in Table 2. Average percentage yields of the other parts approximated those reported by Fry et al. (1962). The average percentages of yield between strains for boneless skinless breast ranged from 23.4 to 29.7 for the males, and from 22.8 to 28.9 for the females. Differences in percentage yields of breast indicated the amount of breast skin varied individually and by strains. The percentage for the skinless thighs ranged from 12.9 to 14.1 in the males, and from 13.3 to 14.8 in the females. This substantiates results published by Fry et al. (1962) showing that the average percentage of breast was highest in male turkeys and that females had a larger percentage of thigh meat. These data indicated that percent of skin on both breast and thighs was about the same for males and females. The mean weights of the skinless breasts and thighs of the males were 6.35 and 3.17 pounds, respectively, and for the females these values were 2.80 and 1.55 pounds. The percentages of the skinless breast and thigh of ready-to-cook turkey expressed as averages were 27.1 and 13.5 for the males and 25.4 and 14.2 for the females, respectively. Table 3. contains the analyses of variance of yield of skinless breast and thigh meat. The 12 strains differed significantly in both absolute and relative yields of skinless breast meat, while the skinless thigh yields did not differ in absolute weights.
Downloaded from http://ps.oxfordjournals.org/ at University of Rhode Island on April 4, 2015
was wiped from the exteriors and body cavities before the birds were cut into parts. The method of cutting up the turkeys followed the suggestion of the NCM-7 meat yields bulletin (Swanson et al., 1964) with the following exeptions: (1) the neck was skinless, (2) the breast was boneless and skinless, and (3) thighs were deboned and skinless. Parts were weighed to the nearest one-hundredth of a pound as soon as they were detached from the carcass. The yield for each part was calculated as the percentage of the ready-to-cook carcass, minus giblets. Hereafter, all breast and thigh meat will be considered boneless, unless otherwise specified. The second experiment consisted of 124 commercial Grade A Bronze toms, weighing 22-24 lbs. ready-to-cook. They were processed, Cryovac packed and blast frozen at - 3 7 ° C . ( - 3 5 ° F . ) . These birds were also held at - 1 8 ° C . (0°F.) in public storage until they were cut-up. After thawing 36 to 42 hours at approximately 21°C. (70°F.), each bird was skinned and deboned. The deboned, skinless breasts and thighs were separately weighed to the nearest one-hundredth of a pound and the skin weight was determined by difference between the sum of the breast and thigh weights and the completed roll weight. The 124 rolls were prepared by placing the anterior ends of the left and right breasts on the skin parallel to each other but in opposite directions. The skinless thighs were placed on top of the breasts, the skin overlapped, and the rolls hand stitched. Each roll contained the entire boneless breast and thigh muscles of the whole ready-tocook turkey, and only enough skin was utilized to enclose them completely.
376
M. H. TAYLOR AND J. L. FRY TABLE 2.—Average yields of boneless breast and boneless thigi hs from male and female turkeys of twelve different strains Ev. Wt.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
Breast Lbs.
Breast
24.87 23.14 25.94 23.33 25.01 22.50 23.19 23.19 22.66 16.87 25.43 25.20
7.93 7.60 8.19 7.87 8.68 7.05 7.40 7.59 6.83 5.80 8.30 7.93
31.9 32.8 31.6 33.7 34.7 31.3 31.9 32.3 30.1 34.4 32.6 31.5
Ave.
23.44
7.60
32.4
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
11.15 10.67 11.84 10.85 11.53 11.19 11.29 11.04 11.24 7.75 12.38 10.91
3.22 2.99 3.42 3.41 3.47 3.26 3.20 3.20 3.13 2.26 3.78 3.01
29.1 28.0 28.9 31.4 30.1 29.1 28.3 29.0 27.9 29.2 30.5 27.6
Ave.
10.99
3.20
29.1
%
Skinless Breast Lbs.
Skinless Breast
%
Thighs Lbs.
%
Skinless Thighs Lbs.
Skinless Thighs
Thighs
%
Males (Toms) 26.6 6.61 27.9 6.46 27.3 7.07 29.4 6.98 29.7 7.42 26.9 6.05 24.8 5.76 26.9 6.23 23.4 5.30 28.8 4.85 27.8 7.07 25.3 6.38
3.85 3.35 3.98 3.50 3.71 3.45 3.56 3.43 3.56 2.54 3.91 3.85
15.5 14.5 15.3 15.0 14.8 15.3 15.4 14.8 15.7 15.1 15.4 15.3
3.34 2.98 3.63 3.16 3.18 3.14 3.11 3.27 3.02 2.29 3.48 3.40
13.4 12.9 13.6 13.3 12.9 14.0 13.4 14.1 13.3 13.6 13.8 13.5
27.1
3.56
15.2
3.17
13.5
Females (Hens) 2.54 22.8 2.59 24.3 2.93 24.8 3.00 27.7 2.98 25.9 2.83 25.5 2.92 25.9 2.78 25.2 2.76 24.2 2.01 25.9 3.58 28.9 2.62 24.0
1.78 1.73 1.84 1.69 1.86 1.78 1.82 1.78 1.76 1.23 1.95 1.71
16.0 16.2 15.5 15.6 16.1 15.9 16.1 16.1 15.7 15.9 15.8 15.7
1.65 1.58 1.57 1.48 1.64 1.37 1.59 1.57 1.60 1.10 1.83 1.60
14.8 14.5 13.3 13.6 14.2 14.3 13.8 14.2 14.2 14.2 14.8 14.3
1.74
15.9
1.55
14.2
6.35
2.80
There were highly significant differences between strains in relative weights (Table 4). The two sexes differed significantly in both absolute and relative weights of both kinds of meat. The interaction between strain and sex was significant in all analyses except that
25.4
of absolute thigh weights. Since in the other three instances this interaction was highly significant, it may be concluded that sex and strain interact in both absolute and relative weights of breast and thigh meat. The males were consistently heavier than the females in absolute weight of boneless,
TABLE 3.—Analyses of variance of yield of boneless, skinless breast and thigh meat
Source Between strains Between sexes Interaction Error Total
Thigh
Degrees of Freedom
Mean Squares
F Observed
Mean Squares
F Observed
11 1 11 96
2.66 378.53 .96 .11
24.18** 3,441.18** 8.73**
.60 73.59 .15 .34
1.76 216.44** .44
119
Significant at .01 level.
Breast
Downloaded from http://ps.oxfordjournals.org/ at University of Rhode Island on April 4, 2015
Strain No.
377
YIELD OF TURKEY PARTS TABLE 4.—Analyses of variance of angles corresponding to percentages of boneless, skinless breast and thigh meat
Source
Thigh
Breast
Degrees of Freedom
Mean Squares
F Observed
11 1 11 96
10.61 34.15 2.99 0.60
17.68** 56.91** 4.98**
Between strains Between sexes Interaction Error
Mean Squares
F Observed
0.37 10.47 0.52 0.15
2.47** 69.80** 3.47**
119
Total
** Significant at .01 level.
(1) (2) (3) (4)
Yx = Y2 = Y3 = Y =
6.21 1.33 6.21 1.33
+ + + +
0.588 0.221 0.549 1.186
(x (x (x (x
-
10.26) 10.26) 10.26) 10.26)
where x, Yi, and Y2 were the weights in pounds of the roll, breast and skin, respectively, and where Y3 and Y4 were the angles corresponding to the percentage weights of breast and skin, respectively.
The regression coefficients for both breast and skin weights on roll weight were highly significant by t-test. A nonsignificant coefficient of regression was found for percentage breast weight on roll weight, but a significant coefficient was calculated in the case of percentage skin weights. Therefore, it seems feasible from a practical viewpoint to resort to the absolute rather than to the relative weights. Applying these regression equations it is possible to estimate the breast and skin component parts in a marketable turkey roll. From a practical viewpoint tables are more popular than equations; therefore, the fiducial limts of the byx's are presented in Table 5. for the absolute and relative skin and breast portions of the rolls. Accordingly, in Table 6 the fiducial limits for the absolute and relative skin and breast portions were estimated for the heaviest (11.29 lbs.) and the lightest (9.21 lbs.) roll weights in the sample studied. This esTABLE 5.—Fiducial limits for the coefficients of regression (byx)1 Dependent variable Y 1 Breast weight lbs. Angles corresponding to percent breast Skin weight lbs. Angles corresponding to percent skin l
X = roll weight in pounds.
Lower Level
Upper Level
0.493
0.683
-0.740 0.108
1.172 0.334
0.280
2.092
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skinless breast meat (Table 2). Yet the highly significant interaction between sex and strain for this trait (Table 3) reflect a wide variation in its sex difference. For example, in strain Number 5 sex difference was almost twice as much as that of strain No. 9 (4.44 vs. 2.54 lbs., respectively). In the second experiment, 124 rolls were made from whole ready-to-cook torn turkeys (average weight 22.37 lbs.). Each roll comprised all of the skinless breast and thigh meat of the ready-to-cook turkey and only enough skin to enclose the meat. In each roll the absolute and relative weights of each kind of meat were established. Percentage values were converted to degrees of an angle for computing regression equations. The average weight of the rolls was 10.26 pounds, containing 60.50% of breast meat (6.21 lbs.), 26.60% of thigh meat (2.73 lbs.), and 12.90% of skin (1.33 lbs.). Regression equations for breast and skin weights on roll weights were established as follows:
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M. H. TAYLOR AND J. L. FRY TABLE 6.-—Fiducial
limits for skin and breast meat in turkey rolls made from natural proportions of whole torn turkeys
Lightest roll (9.21 lbs.) Min. Av. Max. Skin weight lbs. Percent skin Breast weight lbs. Percent breast
.98 10.40 5.49 58.52
1.10 11.43 5.59 59.62
X = 10.26 + 0.846 (Yi - 6.21) + 0.667 (Y2 - 2.73), where Y2 and Y2 are the boneless, skinless breast and thigh weights in pounds, respectively. SUMMARY Two experiments were designed to determine the yield of various parts of ready-tocook turkeys, and to find the relationship of these parts to the composition of turkey rolls. In the first experiment 120 turkeys, five of each sex from 12 different strains were cut up and the absolute and relative weights of their different parts established. The mean weight of the boneless, skinless breasts and thighs of the males were 6.3S and 3.12 pounds, respectively. For the females these values were 2.80 and 1.56 pounds. These parts represented 27.1% and 13.2% of the whole ready-to-cook turkey for the males, and 25.4% and 14.2% for the females. In the second experiment, 124 rolls were made from 124 male turkeys. Each roll comprised all the boneless, skinless breast meat, thigh meat and the sufficient skin to completely enclose the roll. In each roll the absolute and relative weights of each kind
1.44 13.20 6.72 59.25
1.56 14.31 6.82 61.59
1.67 15.46 6.91 62.66
of meat were estimated. The average roll weight of 10.26 pounds contained 60.50% of breast meat (6.21 lbs.), 26.60% thigh meat (2.73 lbs.), and 12.98% of skin (1.33 lbs.). Regression equations for breast and skin weights on roll weights were established. It was thus possible to estimate each of these two components in marketable turkey rolls. Regression coefficients for both breast and skin weights on roll weights were highly significant, (byx = 0.588 and 0.221 lbs., respectively). An insignificant coefficient of regression (0.549%) was found for percentage breast weight on roll weight, but a significant coefficient was established in the case of percentage skin weight (byx = 1.186%). These estimates provide adequate market specifications for composition of turkey rolls which are of interest to both processors and consumers. REFERENCES Fry, J. L., O. S. Rao and L. D. Rasplicka, 1962. Factors affecting the yield of turkey parts. Poultry Sci. 4 1 : 1299-1303. Swanson, M. H., C. W. Carlson and J. L. Fry, 1964. Factors affecting poultry meat yields. North Central Regional Research Publication No. 158. Station Bulletin 476, University of Minnesota. U.S. Department of Agriculture, 1961. Turkey performance tests, 1961. Agricultural Research Service, U.S.D.A., ARS. U.S. Department of Agriculture, 1964. Poultry Inspector's Handbook, 1964. Agriculture Marketing Service, Poultry Division, U.S.D.A., AMS.
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tablished ranges for the amount of breast, thigh and skin in turkey rolls. The following multiple regression equation combines both breast (Yi), and thigh (Y2) meat in the prediction of roll weight (X):
1.22 12.48 5.69 60.75
Heaviest roll (11.29 lbs.) Min. Av. Max.