CHARACTERISTICS OF RESTRUCTURED BEEF STEAKS CONTAINING MECHANICALLY DEBONED MEAT 1 R. A. Field, A. Booren, S. A. Larsen and J. L. Kinnison University of Wyoming Agricultural Experiment Station, Laramie 82071 SUMMARY Restructured beef steaks containing 20% fat were manufactured with O, 5, 10, 15 or 20% mechanically deboned meat (MDM) from neck bones of steers (MDM =.8% calcium) or neck bones of cows (MDM =.5% calcium). Panel scores for flavor were not significantly different (P<.05) among formulations but steaks containing the most MDM had superior scores for juiciness. Grittiness was the only trait where differences in least-squares means for steaks containing MDM from neck bones of steers vs cows approached significance (P<.O5). Overall acceptance of the restructured beef steaks containing MDM was not significantly different from that of controls. Steaks containing 10% MDM had a softer more acceptable cooked outer surface than controls. Steaks containing 15 or 20% MDM had a softer outer surface than the controls but these steaks had mushier interiors. Steaks containing 5% MDM were similar to the controls (0% MDM) for all characteristics studied. Therefore, the addition of 5% MDM to restructured steaks can reduce costs without changing steak quality. MDM added to restructured steaks at the 10% level can improve quality and reduce costs at the same time. (Key Words: Mechanically Deboned Meat, Restructured Steaks, Palatability.) INTRODUCTION Restructured beef steaks can be made from less desirable cuts of meat and low quality carcasses which are usually used for ground beef thereby increasing the monetary return. One problem associated with restructured steaks prior to cooking is discoloration of the lean. Cooked restructured steaks are often ~Technical Journal Article 904, Department of Animal Science, University of Wyoming, Laramie. criticized because of a swollen and deformed appearance, a tough "hard-to-cut" surface and a poor texture. Research directed toward improving restructured meat has been conducted (Schwartz and Mandigo, 1974; Mandigo, 1975; Cross and Stanfield, 1976; Campbell et al., 1977). Nevertheless, consumer complaints regarding restructured meat are still common. Mechanically deboned meat (MDM) may be of value in improving quality of restructured steaks since it is high in heme pigments which produce a bright red color and low in strands of connective tissue which are detrimental to binding capacity. MDM improves the textural characteristics of bologna and ground beef patties (Field, 1976; Cross et al., 1977). The objective of our study was to determine what effect the addition of MDM would have on characteristics of restructured beef steaks. MATERIALS AND METHODS Treatment Formulation. Restructured beef steaks containing 20% fat were prepared from frozen cow meat, fresh Utility grade chucks, beef trimmings and MDM. The experimental design was a 2 x 5 factorial with two sources of MDM added at the 0, 5, 10, 15 or 20% levels. One lot of MDM was prepared using neck bones from Good and Choice grade steers and a second lot of MDM was prepared using neck bones from Canner and Cutter cows. Characteristics of each lot of MDM, determined as described by Field et al. (1976) are shown in table 1. The same Beehive deboner equipped with a cylinder with.46 mm holes was used for both lots of MDM. MDM was chilled to 1 C with dry ice within 10 min after deboning and then frozen for 5 days prior to use. All meat except the MDM was processed through the Urschel Comitrol 2100 equipped with a 3-K-030270-D head and a standard impeller (61682). Prior to blending MDM in, fat content was determined and adjusted with beef fat as necessary. A commercial seasoning con- 1289 JOURNAL OF ANIMAL SCIENCE, Vol. 45, No. 6 (1977)
1290 FIELD ET AL. TABLE 1. COMPOSITION OF MECHANICALLY DEBONED MEAT USED IN RESTRUCTURED BEEF STEAKS a Source of MDM Moisture Protein Fat Ash Calcium Neck bones from: Good and choice steers b 64.9 18.1 13.5 3.0.8 Canner and cutter cows c 68.7 17.4 12.0 1.9.5 aall data expressed as a percentage of fresh weight. bmdm yielded 54.9% of the neck bone weight and was 18 C immediately after deboning. MDM was chilled to 1 C within 10 min after deboning. CMDM yielded 45.9% of the neck bone weight and was 11 C immediately after deboning. MDM was chilled to 1 C within 10 rain after deboning. taining 170 g of hydrolyzed vegetable protein and 142 g of salt per 45 kg of meat was added and the product was blended 8 min and made into 4.5 kg logs using a vacuum stuffer. Temperature of the meat logs out of the stuffer was 3 C. The logs were wrapped in polyvinyl chloride film, frozen at -31 C for 24 hr, and then transferred to a -4 C tempering cooler for 72 hours. The film was removed and the logs, approximately 50 cm in length, were pressed under 454 kg of pressure in a modified New York strip die and cut into 2.38 cm thick steaks weighing about 226 g each. The steaks were vacuum packaged, frozen at -40 C for 40 min and then stored at -31 C for approximately 3 months. Frozen steaks were placed 7.6 cm from the preheated element of an electric broiler and broiled 11 min on one side, turned over, and broiled 9 min on the other side. Internal temperature of the steaks when they were removed from the oven was approximately 57 C. Panel Evaluation. Eight panel members experienced in testing MDM as well as other meat were served hot sections from each steak on heated plates. The panel rated each steak for juiciness on an unstructured scale (horizontal line) which was labeled extremely juicy on one end of the line and extremely dry on the other end. The same type of unstructured scale, labeled no detectable grit on one end and extreme grittiness on the other, was used for scoring grittiness. Scores were converted to numerical values with the aid of a 9 cm ruler with the distance between 0 and 1 cm being scored as 1, between 1 and 2 cm being scored as 2, et cetera. Lowest numbers (0 to 1) were assigned to the ends of the scales labeled no detectable grit or extremely juicy. Flavor and overall satisfaction were scored on a 9-point hedonic scale (1 = dislike extremely and 9 = like extremely). Panelists evaluated steaks containing 0, 5, 10, 15, or 20% MDM at each session for a total of 12 sessions. Steaks containing different sources of MDM (table 1) were evaluated at alternate sessions so that samples from each batch of MDM were served six times. Instron Measurements. Parameters for hardness of surface, mushiness of interior, elasticity of surface and thickness of the cooked steaks were measured objectively using a 1.11 cm diameter Magnus-Taylor puncture probe on cooked steaks tempered at 21 C and 65% relative humidity for 5 to 7 hours. Three replicate measurements were made in different areas near the center of each steak. Gauge length was set at 3 centimeters. By subtracting crossbead travel prior to contact with the steak surface from gauge length, the thickness of the steak could be determined. The amount of pressure for the probe to break the crusted surface of the steak on the side heated for 9 min was recorded as hardness of surface (figure 1). Elasticity was the distance traveled by the probe after contact with the steak surface before a break in the surface of the steak occurred. After the crusted surface of the steak was penetrated by the Magnus-Taylor puncture probe, a reduction in pressure was recorded as the probe continued to penetrate the interior of the steak (figure 1). The reduction in pressure was used as a measure of mushiness of the interior portion of the steak. Statistical Analyses. The data were analyzed by analysis of variance procedures (Harvey, 1960). Difference between sources of MDM as well as between steaks containing 0, 5, 10, 15 or 20% MDM were tested by Duncan's multiple
RESTRUCTURED STEAKS CONTAINING MDM 1291 LG Q: (3 4 / HICKNESS f~asticity I ] 0 5 I0 15 DISTANCE, rnrn Figure 1. Typical force-distance curve for Maguus- Taylor puncture probe readings on restructured beef steaks. Thickness was the distance traveled before contact with the steak surface minus the three cm gauge length setting; elasticity (mm) was the distance over which the sample was under compression before the peak height was reached; hardness of surface (kg) was the height of the peak; mushiness of interior was the reduction in pressure (g) after the peak. range test (Duncan, 1955). No significant (P<.05) interactions between source of MDM and level of MDM in the steaks were found. RESULTS AND DISCUSSION Characteristics of restructured beef steaks are shown in table 2. No significant differences (P<.05) in weight of the frozen steaks from different formulations were present. In addition, moisture, fat and protein percentages for frozen steaks from the different formualtions were similar (data not shown in tabular form). Panel scores for flavor were not significantly different (P<.05) among formulations but steaks containing the most MDM had superior scores for juiciness (table 2). The finding for juiciness substantiates work of Cross et al. (1977) with ground beef patties containing 0 to 30% MDM. They showed that as the percentage of added MDM increased, panel ratings for juiciness increased. Grittiness scores for steaks containing dif- ferent levels of MDM were not significantly different (P<.05). Nevertheless, there was a tendency for steaks containing higher amounts of MDM to have more undesirable scores for this trait. Grittiness was the only trait where differences in least-squares means for steaks containing MDM from neck bones of Good and Choice steers approached a significant (P<.05) difference when compared to steaks containing MDM from neck bones of Canner and Cutter cows. Therefore, comparisons between steaks from different lots of MDM are not shown in tabular form. Slightly more undesirable grittiness scores in steaks containing MDM from Good to Choice grade steers is related to the higher calcium content (.8 vs.5%) when compared to MDM from neck bones of Canner and Cutter cows (table 1). From a grittiness standpoint, the amount and size of bone in MDM must be considered when determining proportion of MDM that should be added to restructured steaks. Overall acceptance of the restructured beef steaks was not significantly different. The slightly more acceptable juiciness scores and slightly less acceptable grittiness scores with increasing amounts of MDM in the steaks apparently offset each other. Cross et al. (1977) observed that ratings for overall acceptability of patties containing 5, 10, 15 or 20% MDM were greater than for control patties (0% MDM). Color is one factor relating to overall acceptability of the steaks which was not scored in our study because the brighter red, more attractive color of the restructured frozen steaks containing MDM was obvious. In addition, a slightly richer brown surface and a slightly rarer interior in cooked steaks containing increasing amounts of MDM was noted. These color differences were masked by lighting during evaluation to prevent bias on the part of panel members. Instron measurements using the Magnus- Taylor puncture probe showed a significant decrease in hardness of surface with the addition of 10, 15 or 20% MDM (table 2). The "hard-to-cut" surface which often results in steaks being torn apart is one of the most objectionable characteristics of cooked restructured beef steaks. Addition of MDM to restructured steaks at the 10% level is sufficient to decrease hardness which should result in increased consumer acceptance. A further check on characteristics of the surface of the broiled steak was a measure of elasticity. The
1292 FIELD ET AL. TABLE 2. LEAST-SQUARES MEANS AND STANDARD ERRORS FOR CHARACTERISTICS OF RESTRUCTURED BEEF STEAKS Percentage MDM added Trait Control 5 10 15 20 SE Individual frozen steak wt, g 224.8 a 224.4 a 228.0 a 228.2 a 226.9 a 3.06 Panel ratings Flavor d 7.10 a 6.93 a 6.98 a 6.85 a 7.17 a.14 Juiciness e 3.72 a 3.51 a 3.85 a 3.32a, b 2.62 b.27 Grittiness f 1.46 a 1.45 a 1.74 a 1.64 a 1.87 a.16 Overall d 6.85 a 6.82 a 6.70 a 6.85 a 7.18 a.17 Instron values Hardness of surface, kgg 4.10 a 4.30 a 3.48 b 3.29 b 3.50 b.16 Elasticity of surface, m.m h 13.08 a 12.25a, b 11.67 b,c 10.83 c 11.66 c.45 Mushiness of interior, gl 198.4 a 184.7 a 256.8a, b 372.1b, c 429.1 c 51.68 Steak thickness, cm 2.62 a 2.61 a 2.64 a 2.62 a 2.67 a.21 Cooked meat yield, % 72.25 a 69.67 a 71.83 a 72.00 a 70.92 a.73 a'b'cmeans on the same line bearing different letters differ significantly (P<.05). dbased upon a 1 to 9 hedonic scale with 9 being like extremely. evalues from a 1 to 9 overlay placed on an unstructured scale with 1 being extremely juicy and 9 being extremely dry. fvalues from a 1 to 9 overlay placed on an unstructured scale with 1 being no detectable grittiness and 9 being extreme grittiness. gmeasured the ease with which the probe broke the surface of the steak. hthe distance traveled by the probe after contact with the steak surface before a break in the surface of the steak occurred. tmeasured by the reduction in pressure on the probe after the surface was broken. Greater reduction in pressure was associated with a mushier interior. distance the probe traveled before a break in the steak surface occurred was significantly shorter for steaks containing 10% MDM when compared to the control steaks. Steaks containing 10, 15 or 20% MDM were not significantly different from each other for this characteristic. According to Cross et al. (1977) one of the major objections to ground beef patties with 15% or more MDM added was that they were too mushy. The reduction in pressure as the probe broke the crusted surface and continued to penetrate the interior of the steak was recorded as mushiness of the interior portion. No significant differences in mushiness of steaks containing 0, 5, or 10% MDM were found but those containing 15 or 20% MDM had a mushier interior. This objective measure of mushiness correlates well with consumer responses recorded by Cross et al. (1977). Thickness of the control steaks (0% MDM) increased from 2.38 to 2.62 cm during cooking. An increase in thickness during cooking is undesirable because of the swollen and deformed appearance of the steaks. Campbell et al. (1977) reported a similar amount of swelling during cooking for 2.54 cm thick restructured pork steaks. The addition of MDM to restructured beef steaks did not reduce the thickness of the cooked steaks (table 2). Likewise, cooked meat yield, which ranged from 69.67 to 72.25% of the fresh weight, did not change significantly with the addition of MDM. Cross et al. (1977) also reported that levels of MDM and cooking losses were not consistently associated. Field (1976) stated that smokehouse shrinkages of processed meat containing MDM is similar to that of control samples. These data suggest that MDM added at the 10% level can improve the quality of restructured beef steaks because cooked steaks containing 10% MDM have a softer more acceptable outer surface than controls. Steaks containing 5% MDM were similar to the controls (0% MDM) for all traits studied. Therefore, the
RESTRUCTURED STEAKS CONTAINING MDM 1293 addition of 5% MDM to restructured steaks could reduce costs without changing the quality. Restructured steaks containing 15 or 20% MDM had a softer outer surface than the controls but there was a tendency for these steaks to have mushier interiors. LITERATURE CITED Campbell, J. R., K. L. Neer and R. W. Mandigo. 1977. Effects of portion thickness and cooking temperature on the dimensional properties and composition of restructured pork. J. Food Sci. 42:179. Cross, H. R., J. Stroud, Z. L. Carpenter, A. W. Kotula, T. W. Nolan and G. C. Smith. 1977. Utilization of mechanically deboned meat in ground beef. J. Food Sci. 42: (In press). Cross, H. R. and M. L. Stanfield. 1976. Consumer evaluation of restructured beef steaks. J. Food Sci. 41:1257. Duncan, D. B. 1955. Multiple range and multiple F tests. Biometrics 11 : 1. Field, R. A. 1976. Mechanically deboned red meat. Food Technol. 30:(9)38. Field, R. A., W. G. Kruggei and M. L. Riley. 1976. Characteristics of mechanically deboned meat, hand separated meat and bone residue from bones destined for rendering. J. Anita. Sci. 43:755. Harvey, W. R. 1960. Least-squares analysis of data with unequal subclass numbers. USDA, ARS 20--8. Mandigo, R. W. 1975. Restructured meat. Proc. 11th Ann. Meat. Ind. Res. Conf., Chicago, IL. p. 43. Schwartz, W. C. and R. W. Mandigo. 1974. The effect of salt and tripolyphosphate on restructured pork. J. Anita. Sci. 39:973.