- Email: [email protected]
Quality of Roasts from Bulls and Steers of Early and Late Fattening Types
Can. Insf. Food Sci. Technol. J. Vol. 18, No.4, pp. 296-301, 1985
RESEARCH
Quality of Roasts from Bulls and Steers of Early and Late Fattening Types Elizabeth A. Gullett and Donna L. Rowe Department of Consumer Studies and
S.D.M. Jones Department of Animal and Poultry Science University of Guelph, Guelph, Ontario NlG 2Wl
Abstract
(1978) observed that meat from bulls was darker and leaner than that from steers. Riley et 01. (1983) and Winer et 01. (1981) reported that meat from bulls was more variable than meat from steers. The purpose of this study was to examine meat quality differences for bulls and steers of early and late fattening breeds fed to a constant finish. Meat quality was evaluated by sensory evaluation, cooking losses and chemical and physical measurements. The study was part of a larger study examining feedlot performance, carcass composition and efficiency of muscle gain in bulls and steers conducted by the Department of Animal and Poultry Science, at the University of Guelph.
This study determined meat quality differences for bulls and steers of early and late fattening breeds fed to a constant finish. Longissimus dorsi (LD) and Semitendinosus (ST) roasts cooked to 65°C were tested for percent moisture, fat, press fluid, cooking losses, shear values and sensory evaluation utilizing a completely random block design. A trained panel found steer LD roasts more tender than bull (P < 0.05); ST roasts were not significantly different. Early fattening LD and ST roasts were more tender than late fattening roasts (P < 0.05). Roasts from bull and late fattening breeds had more moisture, less fat and greater evaporation losses (P < 0.05).
Resume Cette etude a servi it determiner les differences dans la qualite de la viande provenant de taureaux et de bouvillons de races d'engraissement hatives et tardives nourris jusqu'it un fini uniforme. Des r6tis de Longissimus dorsi (LD) et de Semitendinosus (ST) cuits it 65°C fment analyses pour les teneurs en eau, en gras, en fluide expressible et en pertes it la cuisson, pour les indices de cisaillement et pour revaluation sensorielle utilisant un modele de blocs completement au hasard. Un comite d'experts trouva que les r6tis LD des bouvillons furent plus tendres que ceux des taureaux (P < 0.05); les r6tis ST ne furent pas significativement differents. Les r6tis LD et ST des races hatives fment plus tendres que ceux des races tardiyes (P < 0.05). Les rotis de taureaux et ceux des races tardives furent plus riches en eau, plus pauvres en gras et les pertes it l'evaporation furent plus elevees (P < 0.05).
Materials and Methods The data were collected from two trials which were conducted in 1980/81 and 198I/82 as described by Jones et 01. (1984). The British breed crosses were mainly sired by Hereford bulls with dams being Hereford or small rotational crossbred cows. The large animals were mainly sired by Simmental, Charolais, Maine-Anjou and Blonde D'Aquitaine bulls bred to large rotational crossbred cows. Animals were selected for slaughter once they achieved approximately 6 mrh of subcutaneous fat thickness between the II/12th ribs as determined ultrasonically (Jones et 01., 1984). For Part I Longissimus dorsi (LD) roasts were removed from the right side of the carcass which had aged 7 d, vacuum packaged and held frozen at -18. o C until time of testing. For Part II both Longissimus dorsi (LD) and Semitendinosus (ST) roasts were treated in the same way as LD roasts from Part I.
Introduction Interest in utilizing bull carcasses as meat has developed from reports that bulls grow more rapidly and efficiently and produce heavier leaner carcasses than steers (Seiderman et 01., 1982). The palatability of bull versus steer meat is less clear. Many studies have observed better sensory scores for steers for tenderness and juiciness (Forrest, 1975; Berry et 01.,1978; Winer et 01., 1981; Crouse et 01., 1983). Forrest (1975) also reported better flavour scores but Winer et 01. (1981) obtained superior flavour scores for bullock steaks. Gregory et 01. (1983) and Riley et 01. (1983) observed better tenderness scores for steers but not juiciness scores. Crouse et 01. (1983) and Berry et 01.
Cooking Procedures Four roasts, one from each treatment, were cooked on one day according to a completely random block design. The frozen roasts were thawed at refrigerator
Copyright c 1985 Canadian Institute of Food Science and Technology
296
thawed for 24 h. One sample was taken from the centre of the roast near the portion used for sensory evaluation (muscle) and another from the remainder of the roast (roast). Samples were freeze-dried for 72-96 h. Weight of each sample to the nearest gram was recorded before and after freeze-drying. Percent moisture was calculated based on the difference in weight. Percent fat was determined based on the chloroform-methanol technique of Atkinson et al. (1972). Freeze-dried samples were ground in a Waring blender for 10 s and a 1 to 2 g sample oven dried for fat analysis and results expressed as percent fat of the original sample (before freeze-drying). All tests were done in duplicate and averaged.
Table I. Anchor points for unstructured scales used for evaluation by sensory panel. Sensory parameter Anchor points l Softness Tenderness Initial juiciness Flavour Juiciness Residual tissue Overall acceptability
very very very very very very very
firm - very soft tough - very tender dry - very juicy mild - full meaty dry - very juicy much - very little undesirable - very desirable
'Scores increased toward the right anchor to a maximum of 15.
temperatures for 96 h before cooking, placed fat side up in an uncovered pan and cooked at 163°C to an internal temperature of 65°C as determined by a thermocouple located in the centre of the roast. Roasts were allowed to stand 2 h before slicing during which time the internal temperature rose to 69°C. Cooking losses were calculated as percent loss due to evaporation, drippings and total loss (evaporation plus drippings) determined on a weight basis.
Shear Values and Press Fluid Determination Shear values using the Ottawa Texture Measuring System and the Warner-Bratzler attachment, and press fluid were determined as outlined by Gullet et al. (1983).
Colour Measurement Samples from uncooked roasts 2 mm thick were wrapped in saran and backed by a white plate for colour measurement on a Hunter Color Difference Meter D 25-2 having a 5 cm aperture, and standardized with a white plate (L = 94.5, a = - 1.0, b = 1.9). Four readings per-sample were obtained by rotating the sample 90°C. L,-a,-b values for each sample were reported as the means of the four readings. In addition, hue was calculated as tan-'b/a and chroma as (a 2 + b 2)'I2.
Sensory Evaluation Roasts were sliced from the anterior end of the LD roasts and the posterior end for the ST roasts. Slices 1.2 cm thick adjacent to the thermocouple location were used for sensory samples. Eight trained panelists were presented with 1.2 cm cubes in covered plastic cups for evaluation using a 15 cm unstructured scale and appropriate anchor points (Table 1). Criteria for parameters evaluated were determined as outlined by Gullet et al. (1983). The affective parameter of overall acceptability was used to identify possibly unacceptable samples and not as a measure of difference in acceptability which would require a much larger untrained consumer panel. Four samples were evaluated at each sitting over a three week period. Samples were presented to the panelists in a random order and evaluation took place under red lighting to mask any color differences.
Statistical Analysis Sensory scores were obtained from the unstructured scale by measuring to the nearest 0.1 cm from the left. Scores were analyzed by analysis of variance using the completely random block design used for cooking, including two factors: animal type and castration. A split plot design was incorporated for determining panelist effect. Cooking losses, fat and moisture deter·· mination, shear values, press fluid and colour data were analyzed using analysis of variance. The Statistical Analysis Systems (SAS) were used to conduct analysis of variance (Helwig and Council, 1979).
Moisture and Fat Analysis The remainder of the cooked roasts was frozen until moisture and fat analysis, at which time the roasts were
Table 2. Mean sensory scores' for longissimus dorsi roasts from early and late fattening bulls and steers, Part I. Animal Type Early fattening
Sensory attribute Softness Tenderness Residual tissue Initial juiciness Juiciness Flavour Overall acceptance
Steer Score 9.1 2 9.0 8.4 7.9 8.2 8.4 8.2
Late fattening Bull
SO 3.0 3.2 3.5 3.2 3.1 2.7 3.2
Score 9.1 9.1 8.5 8.1 8.2 8.4 8.1
Steer SO 2.8 2.6 2.8 2.6 2.7 2.7 2.5
Score 8.3 8.1 7.7 7.2 7.5 7.8 7.3
Bull SO 3.0 2.9 2.7 2.8 2.8 2.6 2.8
Score 9.0 9.0 8.1 7.9 8.0 7.6 7.8
SO 3.5 3.3 3.2 3.0 3.1 3.0 3.0
Imean of 62 values score = 15
2 maximum
Can. Ins!. Food Sci. Technol. J. Vol. 18, No.4. 1985
Gullett et al. / 297
Table 3. Mean values l for cooking loss, moisture and fat content, press fluid and shear values for longissimus dorsi roasts from early and late fattening bulls and steers, Part I. Animal Type Early fattening
Late fattening
Steer Cooking losses Evaporation, 0J0 Drip, 070 Total, 0J0 Moisture, 0J0 Fat, 0J0 Press Fluid, 0J0 Shear value (Kg)
Bull
Steer
Bull
Mean
SO
Mean
SO
Mean
SO
Mean
SO
14.04 4.37 18.41 64.84 4.65 44.19 6.19
2.62 0.59 2.55 1.95 1.07 3.85 0.99
15.39 3.94 19.32 65.10 5.31 42.69 6.19
1.34 0.54 1.55 1.77 1.31 3.16 1.31
16.46 3.51 19.97 65.41 4.46 43.32 6.65
1.12 0.91 1.16 1.94 1.09 3.07 1.00
16.67 3.31 19.99 66.62 3.70 43.91 6.56
1.63 0.90 1.87 2.59 1.63 2.25 1.73
'means of 8 values
indicated that no significant differences were obtained for sensory evaluation scores for any of the parameters evaluated. Means and standard deviations for cooking losses, press fluid, shear values, colour measurements, fat and moisture content are shown in Table 3. No significant differences were obtained for analysis of variance for effect of castration. The only significant effect for type of animal was for evaporation loss (P < 0.05) and for drip (P < 0.05) loss. Evaporation losses for late fattening animals were greater than early fattening animals but early fattening animals exhibited greater drip losses (Table 4). Fat content for roasts from early fattening animals was higher than for those from late fattening animals (P < 0.05) accounting for the higher drip losses exhibited by roasts from the early fattening animals.
Table 4. Means! and standard deviations for cooking losses, fat and moisture content in roasts from early and late fattening animals, Part I. Animal Type Early fattening Cooking losses Evaporation, 0J0 Drip loss, 0J0 Total loss, 0J0 Fat, 0J0 Moisture, 0J0
Late fattening
Mean
SO
Mean
SO
14.71b 2 4.16a 18.87a 4.98a 64.97a
2.13 0.59 2.09 1.21 1.80
16.57a 3.4lb 19.98a 4.08b 66.02a
1.36 0.88 1.50 1.40 2.30
IMeans of 16 values 2Means not followed by the same letter are significantly different (P < 0.05)
Results and Discussion Part I
Part II LD roasts and ST roasts from 31 animals were evaluated in 1981/82. Mean panel scores for sensory evaluation of LD and ST roasts are shown in Table
This part of the study included eight animals in each of the four treatments and mean panel scores for LD roasts are presented in Table 2. Analysis of variance
Table 5. Mean I sensory scores for longissimus dorsi and semitendinosus roasts from early and late fattening bulls and steers, Part II. Animal Type Early fattening
Sensory attribute
Steer Score
Late fattening Bull
SO
Score
Softness Tenderness Residual tissue Initial juiciness Juiciness Flavour Overall acceptance
11.03 11.4 10.8 9.4 8.7 7.8 9.1
2.9 2.8 3.1 3.1 3.3 3.0 2.9
9.3 9.6 9.5 8.1 7.2 8.0 8.3
Softness Tenderness Residual tissue Initial juiciness Juiciness Flavour Overall acceptance
8.2 8.6 7.8 9.1 7.9 7.7 7.3
2.7 2.6 3.1 2.6 2.8 2.8 2.7
9.2 9.6 8.8 9.7 8.6 7.8 8.3
Steer SO
Score
Longissimus dorsi 2.8 9.4 2.5 9.7 2.9 9.5 2.6 9.2 2.8 8.4 2.4 7.7 8.7 2.4 Semitendinosus 7.1 2.4 2.6 7.7 2.9 6.7 2.5 8.9 2.7 7.6 7.5 3.0 2.4 6.1
Bull SO
Score
SO
3.2 2.9 3.5 2.9 2.9 2.7 3.2
8.6 8.5 8.1 9.8 8.7 7.5 7.8
2.7 3.1 3.4 2.6 3.1 2.6 2.8
3.1 3.1 3.2 2.6 2.6 3.1 3.1
7.6 8.2 7.3 7.9 7.2 7.4 6.9
3.2 3.1 3.3 2.7 2.7 3.0 3.1
!means of 63 values 2means of 55 values 3maximum score = 15
298 / Gullett et al.
J. InSf. Can. Sci. Technol. Aliment. Vol. 18, No.4, 1985
cant differences were observed for juiciness in LD roasts. No significant differences in flavour were observed for either LD or ST roasts. Samples from early fattening animals were scored more acceptable than samples from late fattening animals (P < 0.05). However, this cannot be taken as a predictor of consumer acceptance because of the size and experience of the panel. Mean values for cooking losses, moisture and fat content, press fluid and shear values for LD and ST roasts are shown in Table 6. For evaporation losses LD and ST roasts from bulls and total losses for LD roasts were significantly greater (P < 0.01) than those from steers regardless of animal type. No significant differences in drip loss were observed. ST roasts from late fattening animals exhibited greater evaporation losses than those from early fattening animals (P < 0.05). LD and ST roasts from bulls contained more moisture and less fat than those from steers (P < 0.05). LD roasts from late fattening animals contained more roast moisture than those from early fattening animals. This was not reflected in press fluid values where ST roasts from early fattening animals had higher percent press fluid (P < 0.05). However, LD roasts from early fattening steers showed higher percent press fluid and LD roasts from late fattening bulls showed higher percent press fluid. This was in agreement with juiciness scores for the LD roasts. Samples from LD and ST roasts from late fattening animals
5. Analysis of variance showed that samples from LD roasts from steers were judged more tender than samples from bulls for softness, tenderness after 3 chews, and residual tissue (P < 0.05). No significant differences in the tenderness parameters for castration were observed for ST roasts. Samples from early fattening type animals were judged more tender for all three tenderness attributes than samples from late fattening type animals for both LD and ST roasts (P < 0.05). Since bulls required an average of 200 d on feed to reach the desired finish compared to 184 d for steers, and late fattening type steers required 215 d and bulls 242 d compared to 152 d for early fattening type steers and 160 d for bulls (Jones et al., 1984) maturity is probably a contributing factor to the differences in tenderness obtained here. The difference between days on feed for steers and bulls was not significant (P < 0.05) and this is reflected in the significant difference (P < 0.05) in tenderness obtained for the LD roasts but not for the ST roasts. Whereas the difference for days on feed was significant (P < 0.05) for animal fattening type and this was reflected in significant differences (P < 0.05) in tenderness for both LD and ST roasts. The effect of castration on juiciness differed between early and late fattening type animals for ST roasts. Samples from bulls were judged to be more juicy (P < 0.05) for early fattening type animals whereas samples from steers were judged more juicy for late fattening type animals (P < 0.05). No signifi-
Table 6. Mean I values for cooking loss, moisture and fat content, press fluid and shear values for longissimus dorsi and semitendinosus roasts from early and late fattening bulls and steers, Part II. Animal Type Early fattening
Cooking losses Evaporation, 0J0 Drip, 0J0 Total, 0J0 Moisture, 070 Roast Muscle only Fat, 0J0 Roast Muscle only Press fluid, 0J0 Shear value (Kg)
Late fattening Bull
Steer Mean
SD
8.21 2.42 10.62
1.80 0.67 2.30
10.31 2.39 12.71
52.77 67.01
4.18 4.66
22.84 5.57 52.66 5.69
4.94 5.45 2.73 1.35
Steer
Mean SD Longissimus dorsi roasts
Bull
Mean
SD
Mean
SD
2.23 0.89 2.64
9.07 2.51 11.57
1.02 1.29 2.19
10.07 2.81 12.90
1.46 0.56 1.45
56.56 68.80
6.84 2.38
56.27 67.61
3.64 1.88
60.47 68.33
3.75 I.l0
17.16 3.27 49.15 5.99
7.79 0.93 2.54 1.35
17.69 4.70 50.99 6.47
4.57 I.l5 4.40 1.46
12.69 3.63 52.59 7.47
4.84 1.17 2.78 2.21
Semitendinosus roasts Cooking losses Evaporation, 0J0 Drip, 0J0 Total, 0J0 Moisture, 0J0 Roast Muscle only Fat, 0J0 Roast Muscle only Press fluid, 0J0 Shear Value (Kg)
11.35 1.05 12.40
1.30 0.50 1.71
12.31 0.87 13.16
1.32 0.54 1.79
13.26 0.94 14.14
I.l7 0.48 1.58
15.79 1.51 17.30
0.84 0.44 1.07
64.91 67.10
2.22 2.14
67.40 69.15
0.95 0.88
65.09 67.23
1.81 1.31
66.93 67.94
1.85 1.74
6.01 4.81 54.50 6.80
2.48 3.20 2.50 0.90
3.73 3.52 56.27 6.29
0.86 0.88 3.47 I.l6
5.25 4.51 53.80 8.06
1.25 1.05 2.23 1.39
3.41 3.07 52.00 7.19
1.00 1.22 3.55 I.l3
Imeans of 8 values 2means of 7 values Can. Insi. Food Sci. Technol. J. Vol. 18. No.4, 1985
Gullett et al. / 299
Table 7. Mean l values for colour measurements of raw samples of longissimus dorsi and semitendinosus muscles from steers, and bulls of early and late fattening types, Part II. Animal Type Early fattening
Colour parameter
Steer
Late fattening Bull
Mean
SD
Hunter L Hunter aL Hunter bL Hue (tan -Ib/a) Chroma (a 2 + b 2)'12
34.7 15.7 9.6 31.6 18.4
2.5 2.4 0.9 2.9 2.4
Hunter L Hunter aL Hunter b L Hue (tan -Ib/a) Chroma (a 2 + b 2)'12
36.7 13.5 9.5 35.3 16.5
2.0 1.2
0.7 2.9 1.1
Steer
Mean SD Longissimus dorsi roasts 35.0 2.9 12.8 1.4 8.7 1.3 34.2 4.3 15.0 1.8 Semitendinosus roasts 38.8 2.5 15.0 1.4 0.7 9.5 32.6 3.1 17.8 1.2
Bull
Mean
SD
Mean
SD
34.3 15.2 8.8 30.3 17.6
3.2 2.9 0.9 3.6 2.9
32.4 15.1 8.1 28.4 16.8
2.6 1.4
35.6 14.5 9.4 33.3 17.3
2.1 1.9 0.5 4.0 1.6
35.6 16.1 9.4 30.2 18.7
1.1
4.0 1.2
3.7 1.1
I.5 3.8 1.4
'means of 8 values 2means of 7 values
exhibited larger shear values (P < 0.05) which agrees with panel scores for tenderness. Larger shear values (P < 0.05) were obtained from ST roasts from steers than bulls but no significant difference was observed for LD roasts. These data indicate that roasts from early and late fattening animals differ in quality characteristics. Roasts from late fattening animals showed greater cooking losses, contained a higher moisture content and more press fluid than roasts from early fattening animals. Similarly roasts from bulls exhibited higher evaporation and total cooking losses and higher moisture content and percent press fluid for ST roasts. Cooking loss through evaporation appears to be associated with a high moisture content but does not necessarily produce a less juicy final product. Mean values for colour measurements are shown in Table 7. Hunter a L and chroma values obtained for LD roast samples exhibited a castration by animal type interaction (P < 0.05). This interaction resulted from castration effects being obtained for early fattening animal types but not for late fattening animal types. Samples from bulls from early fattening types exhibited lower Hunter aL values (P < 0.05) and this was reflected in lower chroma (P < 0.01) for these samples. Calculation of hue values showed a significant effect for animal type but not for castration. Samples from early fattening animals were less red than samples from late fattening animals (P < 0.05). No animal type by castration interaction was obtained for samples from ST roasts. Hunter L values (P < 0.05), Hunter aL values (P < 0.05), and chroma (P < 0.05) were all affected by animal type. Samples from late fattening animal types were darker and exhibited higher aL values which were reflected in higher values for chroma. Hunter aL values (P < 0.01), chroma (P < 0.01) and hue (P <0.05) were affected by castration. Hunter a L values were lower for steers than for bulls and this was reflected in lower values for chroma. However, values obtained for hue indicated that sam300 / Gullett et al.
pIes from steers were more red than those from bulls. The presence of fat within the Longissimus dorsi muscle would affect the colour measurement and could account for the different results for the two muscles. The leaner Semitendinosus muscles were more sensitive to colour effects being affected by both castration and animal type. Samples from steers were more red but less intense than those from bulls, whereas samples from late fattening animal types were darker and more intense but did not differ in hue from samples obtained from early fattening animal types. These colour differences could affect consumer acceptance of the raw meat at time of purchase, for example, meat from bulls of late fattening animals might be rejected on a colour basis. The greater number of significant differences obtained in Part II than in Part I may be influenced by the fact that the late fattening type animals in Part II were on feed longer (steers 43 d longer and bulls 60 d longer) and thus were more mature than the animals slaughtered in Part I. This work supports the work of others in that LD roasts from bulls were judged less tender than those from steers (Crouse et al., 1983; Gregory et al., 1983; Rileyetal., 1983; Wineretal., 1981; Berry et al., 1978; and Forrest, 1975). This work differed in that the animals in this study were compared at the same level of finish (subcutaneous fat) rather than being slaughtered at a constant age or constant weight. However, the fact that ST roasts did not differ for tenderness and that both ST and LD roasts did not differ in flavour and were not consistent for juiciness warrants further examination of utilizing bull meat. Examination of the standard deviations presented in Tables 2, 3, 5 and 6 do not support the observations of Riley et al. (1983) and Winer et al. (1981) that bull meat is more variable than steer. This study suggests that tender cuts of bull meat such as the LD roasts may be less tender than similar cuts of steer meat. Meat from late fattening type J. Inst. Can. Sci. Technol. Aliment. Vol. 18. No.4, 1985
animals was less tender than meat from early fattening type animals and this difference may be a reflection of the greater maturity of the late fattening type animals. Whether these differences are great enough to influence consumer acceptability is questionable and further study is warranted.
References Atkinson, T., Fowler, V.R., Garton, G.A., Lough, A.K. 1972. A rapid method for the accurate determination of lipid in animal tissues. Analyst 97:562. Berry, B., Joseph, A.L., Wagner, S.B., Jennings, T.G., Matsushima, J.K., Brinks, J.S., Carpenter, J.A., Jr. and Fagerlin, P.T. 1978. Carcass palatability and retail characteristics of steers and short scrotum bulls. J. Anima!. Sci. 47:601. Crouse, J.D., Seideman, S.C. and Cross, H.R. 1983. The effects of carcass electrical stimulation and cooler temperature on the quality and palatability of bull and steer beef. J. Anim·. Sci. 56:81. Forrest, R.J. 1975. Effects of castration, sire and hormone treatments on the quality of rib roasts from Holstein-Friesan males. Can. J. Anim. Sci. 55:287. Gregory, K.E., Seideman, S.C. and Ford, J.J. 1983. Effects of late castration, zeranol and breed group on composition and palatability characteristics of longissimus muscle of bovine males. 1. Anim. Sci. 56:781.
Can. lnst. Food Sci. Technol. J. Vol. 18. No.4, 1985
Gullett, E.A., Jones, S.D.M. and Hines, R.J. 1983. Palatability of longissimus dorsi roasts of young and mature cows. Can. Inst. Food Sci. Techno!. J. 16:19. Helwig, J.T. and Council, K.A. 1970. SAS Users' Guide. SAS Institute Inc., Raleigh, N.C. Jones, S.D.M., Burgess, T.D., Wilton, J.W. and Watson, C.H. 1984. Feedlot performance, carcass composition and efficiency of muscle gain in bulls and steers of different mature size slaughtered at similar levels of fatness. Can. J. Anim. Sci. 64:621 Riley, R.R., Savell, J.W., Murphey, C.E., Smith, G.C., Stiffler, D.M. and Cross, H.R. 1983. Palatability of beef from steer and young bull carcasses as influenced by electric stimulation, subcutaneous fat thickness and marbling. J. Anim. Sci. 56:592. Seideman, S.C., Cross, H.R., Oltjen, R.R. and Scanbacker, B.D. 1982. Utilization of the intact male for red meat production: a review. J. Anim. Sci. 55:826. Winer, L.K., David, P.J., Bailey, C.M., Rend, M., Ringkob, T.P. and Stevenson, M. 1981. Palatability characteristics of the longissimus muscle of young bulls representing divergent beef breeds and crosses. J. Anim. Sci. 53:387.
Accepted July 17, 1985
Gullett et al. / 301
RESEARCH
Quality of Roasts from Bulls and Steers of Early and Late Fattening Types Elizabeth A. Gullett and Donna L. Rowe Department of Consumer Studies and
S.D.M. Jones Department of Animal and Poultry Science University of Guelph, Guelph, Ontario NlG 2Wl
Abstract
(1978) observed that meat from bulls was darker and leaner than that from steers. Riley et 01. (1983) and Winer et 01. (1981) reported that meat from bulls was more variable than meat from steers. The purpose of this study was to examine meat quality differences for bulls and steers of early and late fattening breeds fed to a constant finish. Meat quality was evaluated by sensory evaluation, cooking losses and chemical and physical measurements. The study was part of a larger study examining feedlot performance, carcass composition and efficiency of muscle gain in bulls and steers conducted by the Department of Animal and Poultry Science, at the University of Guelph.
This study determined meat quality differences for bulls and steers of early and late fattening breeds fed to a constant finish. Longissimus dorsi (LD) and Semitendinosus (ST) roasts cooked to 65°C were tested for percent moisture, fat, press fluid, cooking losses, shear values and sensory evaluation utilizing a completely random block design. A trained panel found steer LD roasts more tender than bull (P < 0.05); ST roasts were not significantly different. Early fattening LD and ST roasts were more tender than late fattening roasts (P < 0.05). Roasts from bull and late fattening breeds had more moisture, less fat and greater evaporation losses (P < 0.05).
Resume Cette etude a servi it determiner les differences dans la qualite de la viande provenant de taureaux et de bouvillons de races d'engraissement hatives et tardives nourris jusqu'it un fini uniforme. Des r6tis de Longissimus dorsi (LD) et de Semitendinosus (ST) cuits it 65°C fment analyses pour les teneurs en eau, en gras, en fluide expressible et en pertes it la cuisson, pour les indices de cisaillement et pour revaluation sensorielle utilisant un modele de blocs completement au hasard. Un comite d'experts trouva que les r6tis LD des bouvillons furent plus tendres que ceux des taureaux (P < 0.05); les r6tis ST ne furent pas significativement differents. Les r6tis LD et ST des races hatives fment plus tendres que ceux des races tardiyes (P < 0.05). Les rotis de taureaux et ceux des races tardives furent plus riches en eau, plus pauvres en gras et les pertes it l'evaporation furent plus elevees (P < 0.05).
Materials and Methods The data were collected from two trials which were conducted in 1980/81 and 198I/82 as described by Jones et 01. (1984). The British breed crosses were mainly sired by Hereford bulls with dams being Hereford or small rotational crossbred cows. The large animals were mainly sired by Simmental, Charolais, Maine-Anjou and Blonde D'Aquitaine bulls bred to large rotational crossbred cows. Animals were selected for slaughter once they achieved approximately 6 mrh of subcutaneous fat thickness between the II/12th ribs as determined ultrasonically (Jones et 01., 1984). For Part I Longissimus dorsi (LD) roasts were removed from the right side of the carcass which had aged 7 d, vacuum packaged and held frozen at -18. o C until time of testing. For Part II both Longissimus dorsi (LD) and Semitendinosus (ST) roasts were treated in the same way as LD roasts from Part I.
Introduction Interest in utilizing bull carcasses as meat has developed from reports that bulls grow more rapidly and efficiently and produce heavier leaner carcasses than steers (Seiderman et 01., 1982). The palatability of bull versus steer meat is less clear. Many studies have observed better sensory scores for steers for tenderness and juiciness (Forrest, 1975; Berry et 01.,1978; Winer et 01., 1981; Crouse et 01., 1983). Forrest (1975) also reported better flavour scores but Winer et 01. (1981) obtained superior flavour scores for bullock steaks. Gregory et 01. (1983) and Riley et 01. (1983) observed better tenderness scores for steers but not juiciness scores. Crouse et 01. (1983) and Berry et 01.
Cooking Procedures Four roasts, one from each treatment, were cooked on one day according to a completely random block design. The frozen roasts were thawed at refrigerator
Copyright c 1985 Canadian Institute of Food Science and Technology
296
thawed for 24 h. One sample was taken from the centre of the roast near the portion used for sensory evaluation (muscle) and another from the remainder of the roast (roast). Samples were freeze-dried for 72-96 h. Weight of each sample to the nearest gram was recorded before and after freeze-drying. Percent moisture was calculated based on the difference in weight. Percent fat was determined based on the chloroform-methanol technique of Atkinson et al. (1972). Freeze-dried samples were ground in a Waring blender for 10 s and a 1 to 2 g sample oven dried for fat analysis and results expressed as percent fat of the original sample (before freeze-drying). All tests were done in duplicate and averaged.
Table I. Anchor points for unstructured scales used for evaluation by sensory panel. Sensory parameter Anchor points l Softness Tenderness Initial juiciness Flavour Juiciness Residual tissue Overall acceptability
very very very very very very very
firm - very soft tough - very tender dry - very juicy mild - full meaty dry - very juicy much - very little undesirable - very desirable
'Scores increased toward the right anchor to a maximum of 15.
temperatures for 96 h before cooking, placed fat side up in an uncovered pan and cooked at 163°C to an internal temperature of 65°C as determined by a thermocouple located in the centre of the roast. Roasts were allowed to stand 2 h before slicing during which time the internal temperature rose to 69°C. Cooking losses were calculated as percent loss due to evaporation, drippings and total loss (evaporation plus drippings) determined on a weight basis.
Shear Values and Press Fluid Determination Shear values using the Ottawa Texture Measuring System and the Warner-Bratzler attachment, and press fluid were determined as outlined by Gullet et al. (1983).
Colour Measurement Samples from uncooked roasts 2 mm thick were wrapped in saran and backed by a white plate for colour measurement on a Hunter Color Difference Meter D 25-2 having a 5 cm aperture, and standardized with a white plate (L = 94.5, a = - 1.0, b = 1.9). Four readings per-sample were obtained by rotating the sample 90°C. L,-a,-b values for each sample were reported as the means of the four readings. In addition, hue was calculated as tan-'b/a and chroma as (a 2 + b 2)'I2.
Sensory Evaluation Roasts were sliced from the anterior end of the LD roasts and the posterior end for the ST roasts. Slices 1.2 cm thick adjacent to the thermocouple location were used for sensory samples. Eight trained panelists were presented with 1.2 cm cubes in covered plastic cups for evaluation using a 15 cm unstructured scale and appropriate anchor points (Table 1). Criteria for parameters evaluated were determined as outlined by Gullet et al. (1983). The affective parameter of overall acceptability was used to identify possibly unacceptable samples and not as a measure of difference in acceptability which would require a much larger untrained consumer panel. Four samples were evaluated at each sitting over a three week period. Samples were presented to the panelists in a random order and evaluation took place under red lighting to mask any color differences.
Statistical Analysis Sensory scores were obtained from the unstructured scale by measuring to the nearest 0.1 cm from the left. Scores were analyzed by analysis of variance using the completely random block design used for cooking, including two factors: animal type and castration. A split plot design was incorporated for determining panelist effect. Cooking losses, fat and moisture deter·· mination, shear values, press fluid and colour data were analyzed using analysis of variance. The Statistical Analysis Systems (SAS) were used to conduct analysis of variance (Helwig and Council, 1979).
Moisture and Fat Analysis The remainder of the cooked roasts was frozen until moisture and fat analysis, at which time the roasts were
Table 2. Mean sensory scores' for longissimus dorsi roasts from early and late fattening bulls and steers, Part I. Animal Type Early fattening
Sensory attribute Softness Tenderness Residual tissue Initial juiciness Juiciness Flavour Overall acceptance
Steer Score 9.1 2 9.0 8.4 7.9 8.2 8.4 8.2
Late fattening Bull
SO 3.0 3.2 3.5 3.2 3.1 2.7 3.2
Score 9.1 9.1 8.5 8.1 8.2 8.4 8.1
Steer SO 2.8 2.6 2.8 2.6 2.7 2.7 2.5
Score 8.3 8.1 7.7 7.2 7.5 7.8 7.3
Bull SO 3.0 2.9 2.7 2.8 2.8 2.6 2.8
Score 9.0 9.0 8.1 7.9 8.0 7.6 7.8
SO 3.5 3.3 3.2 3.0 3.1 3.0 3.0
Imean of 62 values score = 15
2 maximum
Can. Ins!. Food Sci. Technol. J. Vol. 18, No.4. 1985
Gullett et al. / 297
Table 3. Mean values l for cooking loss, moisture and fat content, press fluid and shear values for longissimus dorsi roasts from early and late fattening bulls and steers, Part I. Animal Type Early fattening
Late fattening
Steer Cooking losses Evaporation, 0J0 Drip, 070 Total, 0J0 Moisture, 0J0 Fat, 0J0 Press Fluid, 0J0 Shear value (Kg)
Bull
Steer
Bull
Mean
SO
Mean
SO
Mean
SO
Mean
SO
14.04 4.37 18.41 64.84 4.65 44.19 6.19
2.62 0.59 2.55 1.95 1.07 3.85 0.99
15.39 3.94 19.32 65.10 5.31 42.69 6.19
1.34 0.54 1.55 1.77 1.31 3.16 1.31
16.46 3.51 19.97 65.41 4.46 43.32 6.65
1.12 0.91 1.16 1.94 1.09 3.07 1.00
16.67 3.31 19.99 66.62 3.70 43.91 6.56
1.63 0.90 1.87 2.59 1.63 2.25 1.73
'means of 8 values
indicated that no significant differences were obtained for sensory evaluation scores for any of the parameters evaluated. Means and standard deviations for cooking losses, press fluid, shear values, colour measurements, fat and moisture content are shown in Table 3. No significant differences were obtained for analysis of variance for effect of castration. The only significant effect for type of animal was for evaporation loss (P < 0.05) and for drip (P < 0.05) loss. Evaporation losses for late fattening animals were greater than early fattening animals but early fattening animals exhibited greater drip losses (Table 4). Fat content for roasts from early fattening animals was higher than for those from late fattening animals (P < 0.05) accounting for the higher drip losses exhibited by roasts from the early fattening animals.
Table 4. Means! and standard deviations for cooking losses, fat and moisture content in roasts from early and late fattening animals, Part I. Animal Type Early fattening Cooking losses Evaporation, 0J0 Drip loss, 0J0 Total loss, 0J0 Fat, 0J0 Moisture, 0J0
Late fattening
Mean
SO
Mean
SO
14.71b 2 4.16a 18.87a 4.98a 64.97a
2.13 0.59 2.09 1.21 1.80
16.57a 3.4lb 19.98a 4.08b 66.02a
1.36 0.88 1.50 1.40 2.30
IMeans of 16 values 2Means not followed by the same letter are significantly different (P < 0.05)
Results and Discussion Part I
Part II LD roasts and ST roasts from 31 animals were evaluated in 1981/82. Mean panel scores for sensory evaluation of LD and ST roasts are shown in Table
This part of the study included eight animals in each of the four treatments and mean panel scores for LD roasts are presented in Table 2. Analysis of variance
Table 5. Mean I sensory scores for longissimus dorsi and semitendinosus roasts from early and late fattening bulls and steers, Part II. Animal Type Early fattening
Sensory attribute
Steer Score
Late fattening Bull
SO
Score
Softness Tenderness Residual tissue Initial juiciness Juiciness Flavour Overall acceptance
11.03 11.4 10.8 9.4 8.7 7.8 9.1
2.9 2.8 3.1 3.1 3.3 3.0 2.9
9.3 9.6 9.5 8.1 7.2 8.0 8.3
Softness Tenderness Residual tissue Initial juiciness Juiciness Flavour Overall acceptance
8.2 8.6 7.8 9.1 7.9 7.7 7.3
2.7 2.6 3.1 2.6 2.8 2.8 2.7
9.2 9.6 8.8 9.7 8.6 7.8 8.3
Steer SO
Score
Longissimus dorsi 2.8 9.4 2.5 9.7 2.9 9.5 2.6 9.2 2.8 8.4 2.4 7.7 8.7 2.4 Semitendinosus 7.1 2.4 2.6 7.7 2.9 6.7 2.5 8.9 2.7 7.6 7.5 3.0 2.4 6.1
Bull SO
Score
SO
3.2 2.9 3.5 2.9 2.9 2.7 3.2
8.6 8.5 8.1 9.8 8.7 7.5 7.8
2.7 3.1 3.4 2.6 3.1 2.6 2.8
3.1 3.1 3.2 2.6 2.6 3.1 3.1
7.6 8.2 7.3 7.9 7.2 7.4 6.9
3.2 3.1 3.3 2.7 2.7 3.0 3.1
!means of 63 values 2means of 55 values 3maximum score = 15
298 / Gullett et al.
J. InSf. Can. Sci. Technol. Aliment. Vol. 18, No.4, 1985
cant differences were observed for juiciness in LD roasts. No significant differences in flavour were observed for either LD or ST roasts. Samples from early fattening animals were scored more acceptable than samples from late fattening animals (P < 0.05). However, this cannot be taken as a predictor of consumer acceptance because of the size and experience of the panel. Mean values for cooking losses, moisture and fat content, press fluid and shear values for LD and ST roasts are shown in Table 6. For evaporation losses LD and ST roasts from bulls and total losses for LD roasts were significantly greater (P < 0.01) than those from steers regardless of animal type. No significant differences in drip loss were observed. ST roasts from late fattening animals exhibited greater evaporation losses than those from early fattening animals (P < 0.05). LD and ST roasts from bulls contained more moisture and less fat than those from steers (P < 0.05). LD roasts from late fattening animals contained more roast moisture than those from early fattening animals. This was not reflected in press fluid values where ST roasts from early fattening animals had higher percent press fluid (P < 0.05). However, LD roasts from early fattening steers showed higher percent press fluid and LD roasts from late fattening bulls showed higher percent press fluid. This was in agreement with juiciness scores for the LD roasts. Samples from LD and ST roasts from late fattening animals
5. Analysis of variance showed that samples from LD roasts from steers were judged more tender than samples from bulls for softness, tenderness after 3 chews, and residual tissue (P < 0.05). No significant differences in the tenderness parameters for castration were observed for ST roasts. Samples from early fattening type animals were judged more tender for all three tenderness attributes than samples from late fattening type animals for both LD and ST roasts (P < 0.05). Since bulls required an average of 200 d on feed to reach the desired finish compared to 184 d for steers, and late fattening type steers required 215 d and bulls 242 d compared to 152 d for early fattening type steers and 160 d for bulls (Jones et al., 1984) maturity is probably a contributing factor to the differences in tenderness obtained here. The difference between days on feed for steers and bulls was not significant (P < 0.05) and this is reflected in the significant difference (P < 0.05) in tenderness obtained for the LD roasts but not for the ST roasts. Whereas the difference for days on feed was significant (P < 0.05) for animal fattening type and this was reflected in significant differences (P < 0.05) in tenderness for both LD and ST roasts. The effect of castration on juiciness differed between early and late fattening type animals for ST roasts. Samples from bulls were judged to be more juicy (P < 0.05) for early fattening type animals whereas samples from steers were judged more juicy for late fattening type animals (P < 0.05). No signifi-
Table 6. Mean I values for cooking loss, moisture and fat content, press fluid and shear values for longissimus dorsi and semitendinosus roasts from early and late fattening bulls and steers, Part II. Animal Type Early fattening
Cooking losses Evaporation, 0J0 Drip, 0J0 Total, 0J0 Moisture, 070 Roast Muscle only Fat, 0J0 Roast Muscle only Press fluid, 0J0 Shear value (Kg)
Late fattening Bull
Steer Mean
SD
8.21 2.42 10.62
1.80 0.67 2.30
10.31 2.39 12.71
52.77 67.01
4.18 4.66
22.84 5.57 52.66 5.69
4.94 5.45 2.73 1.35
Steer
Mean SD Longissimus dorsi roasts
Bull
Mean
SD
Mean
SD
2.23 0.89 2.64
9.07 2.51 11.57
1.02 1.29 2.19
10.07 2.81 12.90
1.46 0.56 1.45
56.56 68.80
6.84 2.38
56.27 67.61
3.64 1.88
60.47 68.33
3.75 I.l0
17.16 3.27 49.15 5.99
7.79 0.93 2.54 1.35
17.69 4.70 50.99 6.47
4.57 I.l5 4.40 1.46
12.69 3.63 52.59 7.47
4.84 1.17 2.78 2.21
Semitendinosus roasts Cooking losses Evaporation, 0J0 Drip, 0J0 Total, 0J0 Moisture, 0J0 Roast Muscle only Fat, 0J0 Roast Muscle only Press fluid, 0J0 Shear Value (Kg)
11.35 1.05 12.40
1.30 0.50 1.71
12.31 0.87 13.16
1.32 0.54 1.79
13.26 0.94 14.14
I.l7 0.48 1.58
15.79 1.51 17.30
0.84 0.44 1.07
64.91 67.10
2.22 2.14
67.40 69.15
0.95 0.88
65.09 67.23
1.81 1.31
66.93 67.94
1.85 1.74
6.01 4.81 54.50 6.80
2.48 3.20 2.50 0.90
3.73 3.52 56.27 6.29
0.86 0.88 3.47 I.l6
5.25 4.51 53.80 8.06
1.25 1.05 2.23 1.39
3.41 3.07 52.00 7.19
1.00 1.22 3.55 I.l3
Imeans of 8 values 2means of 7 values Can. Insi. Food Sci. Technol. J. Vol. 18. No.4, 1985
Gullett et al. / 299
Table 7. Mean l values for colour measurements of raw samples of longissimus dorsi and semitendinosus muscles from steers, and bulls of early and late fattening types, Part II. Animal Type Early fattening
Colour parameter
Steer
Late fattening Bull
Mean
SD
Hunter L Hunter aL Hunter bL Hue (tan -Ib/a) Chroma (a 2 + b 2)'12
34.7 15.7 9.6 31.6 18.4
2.5 2.4 0.9 2.9 2.4
Hunter L Hunter aL Hunter b L Hue (tan -Ib/a) Chroma (a 2 + b 2)'12
36.7 13.5 9.5 35.3 16.5
2.0 1.2
0.7 2.9 1.1
Steer
Mean SD Longissimus dorsi roasts 35.0 2.9 12.8 1.4 8.7 1.3 34.2 4.3 15.0 1.8 Semitendinosus roasts 38.8 2.5 15.0 1.4 0.7 9.5 32.6 3.1 17.8 1.2
Bull
Mean
SD
Mean
SD
34.3 15.2 8.8 30.3 17.6
3.2 2.9 0.9 3.6 2.9
32.4 15.1 8.1 28.4 16.8
2.6 1.4
35.6 14.5 9.4 33.3 17.3
2.1 1.9 0.5 4.0 1.6
35.6 16.1 9.4 30.2 18.7
1.1
4.0 1.2
3.7 1.1
I.5 3.8 1.4
'means of 8 values 2means of 7 values
exhibited larger shear values (P < 0.05) which agrees with panel scores for tenderness. Larger shear values (P < 0.05) were obtained from ST roasts from steers than bulls but no significant difference was observed for LD roasts. These data indicate that roasts from early and late fattening animals differ in quality characteristics. Roasts from late fattening animals showed greater cooking losses, contained a higher moisture content and more press fluid than roasts from early fattening animals. Similarly roasts from bulls exhibited higher evaporation and total cooking losses and higher moisture content and percent press fluid for ST roasts. Cooking loss through evaporation appears to be associated with a high moisture content but does not necessarily produce a less juicy final product. Mean values for colour measurements are shown in Table 7. Hunter a L and chroma values obtained for LD roast samples exhibited a castration by animal type interaction (P < 0.05). This interaction resulted from castration effects being obtained for early fattening animal types but not for late fattening animal types. Samples from bulls from early fattening types exhibited lower Hunter aL values (P < 0.05) and this was reflected in lower chroma (P < 0.01) for these samples. Calculation of hue values showed a significant effect for animal type but not for castration. Samples from early fattening animals were less red than samples from late fattening animals (P < 0.05). No animal type by castration interaction was obtained for samples from ST roasts. Hunter L values (P < 0.05), Hunter aL values (P < 0.05), and chroma (P < 0.05) were all affected by animal type. Samples from late fattening animal types were darker and exhibited higher aL values which were reflected in higher values for chroma. Hunter aL values (P < 0.01), chroma (P < 0.01) and hue (P <0.05) were affected by castration. Hunter a L values were lower for steers than for bulls and this was reflected in lower values for chroma. However, values obtained for hue indicated that sam300 / Gullett et al.
pIes from steers were more red than those from bulls. The presence of fat within the Longissimus dorsi muscle would affect the colour measurement and could account for the different results for the two muscles. The leaner Semitendinosus muscles were more sensitive to colour effects being affected by both castration and animal type. Samples from steers were more red but less intense than those from bulls, whereas samples from late fattening animal types were darker and more intense but did not differ in hue from samples obtained from early fattening animal types. These colour differences could affect consumer acceptance of the raw meat at time of purchase, for example, meat from bulls of late fattening animals might be rejected on a colour basis. The greater number of significant differences obtained in Part II than in Part I may be influenced by the fact that the late fattening type animals in Part II were on feed longer (steers 43 d longer and bulls 60 d longer) and thus were more mature than the animals slaughtered in Part I. This work supports the work of others in that LD roasts from bulls were judged less tender than those from steers (Crouse et al., 1983; Gregory et al., 1983; Rileyetal., 1983; Wineretal., 1981; Berry et al., 1978; and Forrest, 1975). This work differed in that the animals in this study were compared at the same level of finish (subcutaneous fat) rather than being slaughtered at a constant age or constant weight. However, the fact that ST roasts did not differ for tenderness and that both ST and LD roasts did not differ in flavour and were not consistent for juiciness warrants further examination of utilizing bull meat. Examination of the standard deviations presented in Tables 2, 3, 5 and 6 do not support the observations of Riley et al. (1983) and Winer et al. (1981) that bull meat is more variable than steer. This study suggests that tender cuts of bull meat such as the LD roasts may be less tender than similar cuts of steer meat. Meat from late fattening type J. Inst. Can. Sci. Technol. Aliment. Vol. 18. No.4, 1985
animals was less tender than meat from early fattening type animals and this difference may be a reflection of the greater maturity of the late fattening type animals. Whether these differences are great enough to influence consumer acceptability is questionable and further study is warranted.
References Atkinson, T., Fowler, V.R., Garton, G.A., Lough, A.K. 1972. A rapid method for the accurate determination of lipid in animal tissues. Analyst 97:562. Berry, B., Joseph, A.L., Wagner, S.B., Jennings, T.G., Matsushima, J.K., Brinks, J.S., Carpenter, J.A., Jr. and Fagerlin, P.T. 1978. Carcass palatability and retail characteristics of steers and short scrotum bulls. J. Anima!. Sci. 47:601. Crouse, J.D., Seideman, S.C. and Cross, H.R. 1983. The effects of carcass electrical stimulation and cooler temperature on the quality and palatability of bull and steer beef. J. Anim·. Sci. 56:81. Forrest, R.J. 1975. Effects of castration, sire and hormone treatments on the quality of rib roasts from Holstein-Friesan males. Can. J. Anim. Sci. 55:287. Gregory, K.E., Seideman, S.C. and Ford, J.J. 1983. Effects of late castration, zeranol and breed group on composition and palatability characteristics of longissimus muscle of bovine males. 1. Anim. Sci. 56:781.
Can. lnst. Food Sci. Technol. J. Vol. 18. No.4, 1985
Gullett, E.A., Jones, S.D.M. and Hines, R.J. 1983. Palatability of longissimus dorsi roasts of young and mature cows. Can. Inst. Food Sci. Techno!. J. 16:19. Helwig, J.T. and Council, K.A. 1970. SAS Users' Guide. SAS Institute Inc., Raleigh, N.C. Jones, S.D.M., Burgess, T.D., Wilton, J.W. and Watson, C.H. 1984. Feedlot performance, carcass composition and efficiency of muscle gain in bulls and steers of different mature size slaughtered at similar levels of fatness. Can. J. Anim. Sci. 64:621 Riley, R.R., Savell, J.W., Murphey, C.E., Smith, G.C., Stiffler, D.M. and Cross, H.R. 1983. Palatability of beef from steer and young bull carcasses as influenced by electric stimulation, subcutaneous fat thickness and marbling. J. Anim. Sci. 56:592. Seideman, S.C., Cross, H.R., Oltjen, R.R. and Scanbacker, B.D. 1982. Utilization of the intact male for red meat production: a review. J. Anim. Sci. 55:826. Winer, L.K., David, P.J., Bailey, C.M., Rend, M., Ringkob, T.P. and Stevenson, M. 1981. Palatability characteristics of the longissimus muscle of young bulls representing divergent beef breeds and crosses. J. Anim. Sci. 53:387.
Accepted July 17, 1985
Gullett et al. / 301