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Consumer attitudes towards beef and acceptability of enhanced beef
Meat Science 65 (2003) 721–729 www.elsevier.com/locate/meatsci
Consumer attitudes towards beef and acceptability of enhanced beef K. Robbinsa, J. Jensena, K.J. Ryana, C. Homco-Ryana, F.K. McKeithb, M.S. Brewera,* a
Department of Food Science and Human Nutrition, University of Illinois, 202 Agricultural Bioprocessing Laboratory, 1305 West Pennsylvania, Urbana, IL 61820, USA b Department of Animal Science, University of Illinois, Urbana, IL, USA Received 2 July 2002; received in revised form 30 September 2002; accepted 30 September 2002
Abstract The objective of this study was to evaluate consumer quality characteristics of enhanced steaks and roasts derived from cattle supplemented with vitamin E during finishing, and to assess the attitudes of these consumers towards beef. Twelve steers were fed either a control (E ) diet or a diet supplemented with dl-alpha tocopheryl acetate (E+). Paired strip loins and rounds were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% sodium tripolyphosphate in the final product. Consumers (n=103) evaluated roasts and steaks for juiciness, tenderness, saltiness, and overall acceptability on a 9-point hedonic scale. Enhanced steaks and roasts were more acceptable than non-enhanced controls; E+ steaks were less acceptable than E steaks. A beef quality questionnaire revealed that color, price, visible fat and cut were the most important factors underlying beef steak purchase, while tenderness, flavor and juiciness were weighted most heavily with regard to eating satisfaction. # 2003 Elsevier Science Ltd. All rights reserved.
1. Introduction The beef industry strives to deliver consistent, high quality products for the consumer to purchase at the retail level. The 1990 National Beef Tenderness Survey (Morgan et al., 1991) revealed that beef was too variable in tenderness. In the 1999 National Beef Tenderness Survey (National Cattlemen’s Beef Association, 1999), it had fewer tenderness problems than it did in 1990 (Morgan et al., 1991), however, retail cuts from the round were still at the tough end of the tenderness scale. George, Tatum, Belk, and Smith (1999) reported that approximately 21% of top sirloin steaks and 13% of strip loin steaks purchased from supermarkets in eight major US cities had shear force values above 4 kg. In addition, 72% of the strip loin steaks were rated only ‘‘slightly tender’’ to ‘‘moderately tender.’’ Boleman et al. (1997) reported that consumers were willing to pay a premium for beef top loin steaks with known increased tenderness. When shear force categories were reduced from the 5.90–7.21 kg category to the 4.08–5.40 kg * Corresponding author. Tel.: +1-217-244-2867; fax: +1-217-3333585. E-mail address: [email protected] (M.S. Brewer).
category, or from the 4.08–5.40 kg category to the 2.27–3.58 kg category, a $1.10/kg price difference was placed between each category. Clearly, technologies that could increase tenderness have economic potential in the marketplace. Trained sensory panel evaluations have shown that beef steaks and pork chops are more juicy and tender when enhanced with a phosphate/salt-containing solution (Jensen, McKeith, & Brewer, 2002; Prestat, Jensen, McKeith, & Brewer, 2002; Robbins et al., 2002; Sheard, Nute, Richardson, Perry, & Taylor, 1999; Sutton, Brewer, & McKeith, 1997; Vote et al., 2000). Robbins et al. (2002), Vote et al. (2000) and Sutton et al. (1997) also found increases in saltiness with enhancement. Hoover et al. (1995) reported that injection of 200 mM calcium chloride (to 105% of initial weight) had significant effects on quality when restaurant consumers evaluated beef strip loins. In 2001, The National Cattlemen’s Beef Association (2001) found that a 2.2% calcium chloride marinade had no effect on consumer attributes of beef. Dhanda, Pegg, Janz, Aalhus, and Shand (2001) reported that consumer tenderness, juiciness, flavor and overall acceptability was higher for bison steaks injected to contain 0.3% sodium tripolyphosphate and 0.5% sodium chloride than for control
0309-1740/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0309-1740(02)00274-7
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steaks. However, Robbins et al. (2002) and Jensen et al. (2002) have reported that enhancement with a phosphate/salt solution has detrimental effects on color of beef and pork during retail display. It has been suggested that color instability may be a result of altered susceptibility to oxidation. Dietary vitamin E supplementation in beef cattle may improve beef quality by stabilizing it to oxidation. Lanari, Cassens, Schaefer, and Scheller (1994) reported that dietary vitamin E supplementation greatly increased lipid stability of frozen longissimus lumborum muscle. Lui, Scheller, Schaefer, Arp, and Williams (1994) also reported that lipid oxidation was slower in cooked gluteus medius from vitamin E-supplemented cattle than in that from control, unsupplemented cattle. Although enhancement and vitamin E supplementation may improve beef quality, it is important to understand what the consumer actually desires in beef quality. In a study involving European consumers, Glitsch (2000) reported that Italians rated the origin of the beef as the most important factor in evaluation of fresh meat quality prior to purchase, while Germans, Irish, and Swedes felt color was the dominant factor. Beef flavor, followed closely by tenderness, were most important to ‘‘eating quality.’’ The purpose of the present study was to evaluate the effects of enhancement and/or dietary vitamin E supplementation on consumer quality characteristics of beef, and to assess the attitudes of this consumer population towards fresh beef.
2. Materials and methods Paired beef rounds and strips from vitamin E-supplemented or unsupplemented cattle served as controls or were enhanced. Strip steak and round roast samples were evaluated by a consumer panel. Cook loss and shear force were also determined. Consumers voluntarily completed a beef attitude questionnaire following the beef sensory evaluation. 2.1. Animals and sample manufacture Twelve predominately Angus Hereford steers between 12 and 24 months of age were fed finishing diets at the Southern Illinois University Beef Research Unit, Carbondale, Ill. Animals were randomly assigned to either the vitamin E (E+) or no vitamin E (E ) treatment diets. Cattle assigned to the E+ treatment received diets formulated to provide at least 500 International Units (IU) of vitamin E, as dl-alpha tocopheryl acetate (Hoffman LaRoche, Basel, Switzerland) per day for the final 117 days of feeding. Fifteen days prior to harvest, supplementary vitamin E was withdrawn. Animals were harvested at the University of Illinois Meat
Science Laboratory abattoir. Carcasses were chilled (4 C, 24 h) then evaluated for USDA Quality grades (AMSA, 2001). The a-tocopherol content was determined on ground sirloin samples (13.8+2.7% fat) from each carcass by high performance liquid chromatography (Ralston Analytical, St. Louis, MO). Strip loins (IMPS 180; NAMP, 1997) and rounds (IMPS 169) were removed at 48 h postmortem. Cuts, labeled with animal identification and left/right side designation, were vacuum-packaged and held at 4 C. At 11 days’ postmortem, each of a cut pair was randomly assigned to the pumped (P) or control (C) treatment and pH was determined using a pH Star probe CPU (SSK Technology Inc., Cedar Rapids, IA). Enhanced loins and roasts were injected to 110% of raw weight to contain 0.4% sodium chloride and 0.4% sodium tripolyphosphate (sodium tripolyphosphate anhydrous, sodium polyphosphates, sodium hexametaphosphate, Rhodia Inc., Food Ingredients. Cranbury, NJ) on a finished weight basis. Pump solution (28 C, pH 7.90) was injected using a multiinjector system (Model N50, Wolf-tec, Inc., Kingston, NY). Following injection, cuts were placed into holding tubs, covered, and equilibrated at 4 C for 24 h. Inside round roasts and steaks were vacuum packaged (Multiva, AGW, Koch, Kansas City, MO), blast frozen ( 29 C) and held for 6 weeks. 2.2. Cooking methods Roasts and steaks were thawed at 4 C for a minimum of 48 h. Steaks were cooked to 70 C on a Farberware Open Hearth grill (Model 455N, Walter Kidde, Bronx, NY). Roasts were placed on baking racks and cooked in a convection oven (Model V15, South Bend Range Corporation, South Bend, IN) at 163 C to an internal temperature of 72 C. Internal temperature was monitored using copper-Constantin thermocouples (Type T, Omega Engineering, Stamford, CT) inserted into the geometric center and monitored with a Barnant scanning thermocouple thermometer (Model 692-8000, Barnant Co., Barrington, IL). 2.3. Consumer evaluation Potential panelists (n=112) were recruited from a database of consumers who have participated in previous sensory evaluation studies. Consumers were given appointments with 10 conducting evaluations during each 30-min session. Each consumer received four (E P, E+P, E C, E+C) steak samples (2.54 2.54 2.54 cm) followed by four (E P, E+P, E C, E+C) roast samples (2.54 2.54 2.54 cm) served individually in 30-ml plastic cups (Solo, Champaign, IL) labeled with three-digit random numbers. Sample presentation
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order was randomized from 10-member consumer group to group. Evaluation was accomplished using a 9-point hedonic scale. Following sample evaluation, consumers were asked to complete a questionnaire regarding their attitudes and expectations for beef (Fig. 1). Demographic data were also collected. Consumers were compensated for their time. 2.4. Warner–Bratzler shear One sample from each cut, from each treatment (enhancement vitamin E), from each animal (total=96 samples) was cooked as previously described. Cooked steaks and roasts were allowed to cool (25 C) for a minimum of 1 h. A slice (2.5 cm thick) was removed from the center of each roast. Four 1.3-cm cores were removed from each steak and from each roast slice parallel to the muscle fiber orientation. Shearing was accomplished with an Instron model 1122 Universal Testing Machine (Instron, Canton, MA) fitted with a Warner–Bratzler Shear attachment. The full scale load was 10 kg, while the chart drive and cross head speeds were 200 mm/min. The shear force values for the four cores were averaged for each sample. 2.5. Cook loss Raw and cooked weights of roasts and steaks were determined. Cook loss was calculated as: ([raw weight cooked weight]/raw weight) 100. 2.6. Statistical analysis Data were analyzed using a mixed model procedure (SAS, 2000) treating vitamin, enhancement treatment and their interaction as fixed effects. Vitamin treatment nested within animal was treated as a random effect. Means for significant (P < 0.05) effects were separated using probability of difference.
3. Results and discussion All carcasses graded high select (Se+, n=3) or low choice (Ch , n=9) (AMSA, 2001). The a-tocopherol content of ground sirloin samples from vitamin E supplemented steers (8.26+1.55 mcg a-tocopherol/g) was significantly (P < 0.0001) higher than that from the control, unsupplemented steers (2.67+0.62 mcg/g) indicating that the dietary regimen did, in fact, increase tissue vitamin E effects. Pump levels achieved were 9.47 and 9.42% for the rounds and strips, respectively. A total of 103 consumers evaluated the beef roasts and steaks and completed the questionnaire. About half were male and half were female (data not shown). Slightly over half (56%) were under 30 years of age. About 32% had a
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net family income < $20,000; > 43% had two people in the household. About half of this consumer group were the primary food purchaser in the household. The majority (> 80%) of respondents were Caucasian. 3.1. Effects of enhancement Enhancement had a major effect on the sensory quality of steaks and roasts (Table 1). Enhanced steaks and roasts were significantly more tender and juicy than controls. These results support those of trained sensory panel evaluations of enhanced beef (Robbins et al., 2002). In the present study, beef flavor, saltiness and overall acceptability were higher in the enhanced steaks and roasts than in their control counterparts. Warner– Bratzler shear values confirm the consumer-evaluated tenderness increase in that enhanced roasts had lower shear values (Table 1). Hoover et al. (1995) reported that consumers preferred beef strip loins injected with 200 mM CaCl2 solution at 5% (wt./wt.) to controls. Dhanda et al. (2001) also reported higher consumer tenderness, juiciness, flavor and overall acceptability for enhanced bison steaks compared to controls. In the present study, enhancement had no effect (P < 0.05) on cook loss of either roasts or steaks (Table 1). Significant enhancement by vitamin interactions show that E /enhanced steaks had the lowest shear value and highest tenderness, juiciness and overall acceptability scores (Figs. 2 and 3). In contrast, E+/control steaks had the highest shear force and lowest tenderness, juiciness and overall acceptability scores. The E+/control roasts were also least juicy (Fig. 3). The predominant effect appears to be due to enhancement, because, regardless of vitamin E treatment, enhanced steaks and roasts were more juicy and tender, had higher overall acceptability scores and lower shear force values than non-enhanced cuts. 3.2. Effects of vitamin E Supplementation of vitamin E into the diets of finishing steers had no positive effects on sensory scores of either the steaks or roasts and had no effect on cook loss (Table 2). Robbins et al. (2002) reported no vitamin E effects on trained sensory panel evaluations. In the present study, consumers found that steaks from unsupplemented cattle were more salty and had higher beef flavor scores than the E+ steaks. These findings were unexpected and the reason for them is unclear. Lanari et al. (1994) reported that dietary vitamin E had a major impact on lipid stability of frozen longissus lumborum muscle such that TBARS were less than 20% of those from controls. In the present study, TBARS were not determined, however the panel indicated that roasts and steaks were ‘‘neither unacceptable nor acceptable’’ to ‘‘moderately acceptable’’ suggesting that no or few off-flavors or
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Fig. 1. Beef attitude questionnaire.
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Fig. 1. (continued).
odors were present. In addition, roasts and steaks were vacuum packaged before freezing which significantly increases lipid stability. Vitamin E did not improve the quality of either the roasts or steaks. 3.3. Quality differences in various demographic groups Gender had no effect on any of the quality characteristics evaluated. Tenderness and overall acceptability of
roasts differed among the various education categories of consumers (Table 3). Consumers with a high school education or a graduate education rated roasts as more tender and acceptable than did those with some college or a college degree. It may be that consumers quality expectations relative to perceived product cost are weighted differently among these educational groups. Purchaser status affected a number of quality characteristics of roasts as well (Table 4). Those who shared the purchasing responsibility for food for the household
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Table 1 Enhancement effects on consumer characteristics beef steaks and roastsa Characteristic
Enhanced
Control
P value
S.E.M.b
Steaks Tendernessc Juicinessc Beef flavor Saltiness Overall acceptabilityc Shear forcec % Cook loss
7.46 7.29 7.65a 7.02a 7.48 1.16 24.95
6.58 6.55 6.46 b 6.09 b 6.51 2.26 22.68
<0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 0.25
0.13 0.14 0.13 0.13 0.12 0.16 1.13
Roasts Tenderness Juiciness Beef flavor Saltiness Overall acceptability Shear force % Cook loss
6.18a 5.24a 6.71a 6.22a 6.16a 2.47b 35.30
5.05 4.72 5.85 5.55 5.27 3.24 36.66
b b b b b a
<0.0001 0.0096 <0.0001 0.0001 <0.0001 <0.0001 0.33
0.24 0.29 0.13 0.13 0.20 0.14 1.56
a
Means in the same row with like letters do not differ. Standard error of the means. c A significant enhancement vitamin E interaction existed for this characteristic. b
found roasts to be less juicy, beef flavored, salty and overall acceptable than did those who had the primary purchasing responsibility. However, those who were not the primary purchasers of food were a much smaller group (8.7%) than those who shared responsibility (38.8%) or who were primary purchasers of food (52.5%). If we consider only those who purchase or share in purchase responsibility, it may be that those who share the
Table 2 Dietary vitamin E supplementation effects on consumer characteristics of beef steaks and roastsa Characteristic
E+
E
P value
S.E.M.b
Steaks
Tendernessc Juicinessc Beef flavor Saltiness Overall acceptabilityc Shear force, kgc Cook loss, %
6.67 6.68 6.82b 6.34b 6.72 2.10 24.95
7.37 7.15 7.29a 6.76a 7.27 1.77 22.68
0.0066 0.0543 0.0495 0.0400 0.0104 0.18 0.27
0.15 0.16 0.15 0.13 0.13 0.16 1.13
Roasts
Tenderness Juiciness Beef flavor Saltiness Overall acceptability Shear force, kg Cook loss, %
5.46 4.89 6.12 5.76 5.54 3.12 36.48
5.77 5.07 6.44 6.01 5.90 2.59 35.48
0.4846 0.7495 0.1292 0.2427 0.3421 0.18 0.65
0.30 0.38 0.14 0.14 0.25 0.14 1.56
a
Means in the same row with like letters do not differ. Standard error of the means. c A significant enhancement vitamin E interaction existed for this characteristic. b
responsibility are less attentive to product characteristics. Household size had a significant effect on some characteristics of steaks (Table 5). In general, consumers with 54 people in the household found steaks to be more beefy flavored, salty and overall acceptable than did consumers from 2-person households. It may be that those consumers with fewer people in the household are less attentive, in general, to food quality characteristics.
Fig. 2. Enhancement by vitamin E effects on shear force of steaks.
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Fig. 3. Enhancement by vitamin E effects on consumer sensory evaluation of steaks.
3.4. Consumer attitudes Based on responses to the beef attitude questionnaire, consumers felt that an optimal steak should be somewhat marbled (mean=8.7; 15=high) and moderately bright red (5.9; 15=dark red). They were somewhat concerned about added ingredients (8.1; 15=highly concerned) (data not shown). In terms of consumption characteristics, consumers reported that an optimal steak should be very tender (12.6) and juicy (12.8), and have intense beef flavor (12.1); amount of liquid on the plate was less of a concern (8.0). On a 10-point scale, with more points assigned to factors of greater importance, consumers felt that, when making purchasing decisions for fresh prepackaged steaks, the cut (mean=7.6), color (7.5), visible fat (7.1), price (6.9), and amount of liquid in the package (6.6) were the most important factors to consider (data not shown). Glitsch (2000) reported that color was among the most important factors when European consumers Table 3 Consumer educational level effects on quality characteristics of roasts derived from cattle receiving vitamin E supplementationa High Some College Graduate P value school college graduate school Tenderness 5.26a Overall acceptability 6.40a a
4.92ab 4.30b 5.38b 5.23b
5.30a 6.03ab
Means in the same row with like letters do not differ.
0.02 0.01
considered purchasing fresh meat. Carpenter, Cornforth, and Whittier (2001) also reported that the red color of beef was preferred and what consumers look for when purchasing beef. Brewer, Zhu, and McKeith (2001) reported that purchase intent of fresh pork chops paralleled lean appearance and acceptability. Consumers Table 4 Purchaser status effects on consumer sensory characteristics of roasts derived from cattle receiving vitamin E supplementationa Primary Share Not P value purchaser purchasing primary of food responsibility purchaser Tenderness Juiciness Beef flavor Saltiness Overall acceptability a
5.94a 5.27a 6.59a 6.11a 6.08a
5.67ab 4.41b 5.86b 5.44b 5.18b
5.16b 5.78a 6.42a 6.47a 5.92a
0.001 <0.001 0.001 0.001 0.001
Means in the same row with like letters do not differ.
Table 5 Household size status effects on consumer sensory characteristics of steaks derived from cattle receiving vitamin E supplementationa
Beef flavor Saltiness Overall acceptability a
1 person
2 people
3 people
54 people
P value
6.87b 6.76ab 6.97ab
6.87b 6.28b 6.81b
7.22ab 6.60ab 7.18ab
7.57a 6.92a 7.32a
0.0025 0.0265 0.05
Means in the same row with like letters do not differ.
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expressed a higher degree of purchase intent for leaner pork, but found that more marbled pork produced greater eating satisfaction when consumed in a laboratory setting. Added visible fat was a consumer concern in that study as well. In the present study, the servings/ package (5.1), a sale or promotion (5.8) and added ingredients (5.8) were of secondary concern; the store (4.4) and the brand (3.2) had less impact on consumer decision to purchase steaks. Tenderness, juiciness and flavor (12.6, 12.8, and 12.1, respectively, on a 15-point scale) contributed the most to satisfaction when consuming steaks. These results agree with those of Glitsch (2000) who found tenderness and flavor to be the most important factors in ‘‘eating quality’’ of Europeans. In the present study, beef flavor, degree of doneness and total satisfaction with the product were also given more weight in consumers’ expected satisfaction. The National Cattlemen’s Beef Association (2001) also found flavor to be the key factor driving customer satisfaction. Based on their perception of an ‘‘ideal’’ steak, consumers were asked to assign 0–100 points to their average experienced satisfaction with prepackaged steaks purchased at the supermarket. The sample population in this study gave a score of 69.1 for average purchasing satisfaction and 65.5 for average eating satisfaction (data not shown). The average purchasing and eating satisfaction based on consumer perception of an ‘‘ideal’’ beef steak suggests that the beef industry could still make improvements to increase consumer satisfaction. The 2001 Beef Customer Satisfaction study (National Cattlemen’s Beef Association, 2001) suggests that satisfaction ratings could be increased by selecting top choice and select cuts and by more closely monitoring degree of doneness for various steaks. In the current study, the important factors were tenderness and juiciness, both of which are related to quality grade and degree of doneness. Enhancement increased both tenderness and juiciness. In addition, Prestat et al. (2002) and Jensen et al. (2002) reported that enhancement ‘‘protects’’ pork from the ravages of overcooking. Overall, enhancement may allow lower quality grades and higher degrees of doneness to be tolerable without sacrificing consumer satisfaction.
4. Summary Enhancement significantly increased the consumer acceptability of beef steaks and roasts. However, dietary vitamin E supplementation had no effect on consumer characteristics of either. Consumers reported that color, visible fat, price and cut were the most important factors they considered when purchasing. Tenderness, flavor and juiciness, significantly increased by enhancement, were found to be the most important factors with
respect to consumers eating satisfaction. Although some concern was expressed regarding added ingredients in beef steaks, enhancement has the potential to effectively increase tenderness and juiciness of beef roasts and steaks.
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Consumer attitudes towards beef and acceptability of enhanced beef K. Robbinsa, J. Jensena, K.J. Ryana, C. Homco-Ryana, F.K. McKeithb, M.S. Brewera,* a
Department of Food Science and Human Nutrition, University of Illinois, 202 Agricultural Bioprocessing Laboratory, 1305 West Pennsylvania, Urbana, IL 61820, USA b Department of Animal Science, University of Illinois, Urbana, IL, USA Received 2 July 2002; received in revised form 30 September 2002; accepted 30 September 2002
Abstract The objective of this study was to evaluate consumer quality characteristics of enhanced steaks and roasts derived from cattle supplemented with vitamin E during finishing, and to assess the attitudes of these consumers towards beef. Twelve steers were fed either a control (E ) diet or a diet supplemented with dl-alpha tocopheryl acetate (E+). Paired strip loins and rounds were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% sodium tripolyphosphate in the final product. Consumers (n=103) evaluated roasts and steaks for juiciness, tenderness, saltiness, and overall acceptability on a 9-point hedonic scale. Enhanced steaks and roasts were more acceptable than non-enhanced controls; E+ steaks were less acceptable than E steaks. A beef quality questionnaire revealed that color, price, visible fat and cut were the most important factors underlying beef steak purchase, while tenderness, flavor and juiciness were weighted most heavily with regard to eating satisfaction. # 2003 Elsevier Science Ltd. All rights reserved.
1. Introduction The beef industry strives to deliver consistent, high quality products for the consumer to purchase at the retail level. The 1990 National Beef Tenderness Survey (Morgan et al., 1991) revealed that beef was too variable in tenderness. In the 1999 National Beef Tenderness Survey (National Cattlemen’s Beef Association, 1999), it had fewer tenderness problems than it did in 1990 (Morgan et al., 1991), however, retail cuts from the round were still at the tough end of the tenderness scale. George, Tatum, Belk, and Smith (1999) reported that approximately 21% of top sirloin steaks and 13% of strip loin steaks purchased from supermarkets in eight major US cities had shear force values above 4 kg. In addition, 72% of the strip loin steaks were rated only ‘‘slightly tender’’ to ‘‘moderately tender.’’ Boleman et al. (1997) reported that consumers were willing to pay a premium for beef top loin steaks with known increased tenderness. When shear force categories were reduced from the 5.90–7.21 kg category to the 4.08–5.40 kg * Corresponding author. Tel.: +1-217-244-2867; fax: +1-217-3333585. E-mail address: [email protected] (M.S. Brewer).
category, or from the 4.08–5.40 kg category to the 2.27–3.58 kg category, a $1.10/kg price difference was placed between each category. Clearly, technologies that could increase tenderness have economic potential in the marketplace. Trained sensory panel evaluations have shown that beef steaks and pork chops are more juicy and tender when enhanced with a phosphate/salt-containing solution (Jensen, McKeith, & Brewer, 2002; Prestat, Jensen, McKeith, & Brewer, 2002; Robbins et al., 2002; Sheard, Nute, Richardson, Perry, & Taylor, 1999; Sutton, Brewer, & McKeith, 1997; Vote et al., 2000). Robbins et al. (2002), Vote et al. (2000) and Sutton et al. (1997) also found increases in saltiness with enhancement. Hoover et al. (1995) reported that injection of 200 mM calcium chloride (to 105% of initial weight) had significant effects on quality when restaurant consumers evaluated beef strip loins. In 2001, The National Cattlemen’s Beef Association (2001) found that a 2.2% calcium chloride marinade had no effect on consumer attributes of beef. Dhanda, Pegg, Janz, Aalhus, and Shand (2001) reported that consumer tenderness, juiciness, flavor and overall acceptability was higher for bison steaks injected to contain 0.3% sodium tripolyphosphate and 0.5% sodium chloride than for control
0309-1740/03/$ - see front matter # 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0309-1740(02)00274-7
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steaks. However, Robbins et al. (2002) and Jensen et al. (2002) have reported that enhancement with a phosphate/salt solution has detrimental effects on color of beef and pork during retail display. It has been suggested that color instability may be a result of altered susceptibility to oxidation. Dietary vitamin E supplementation in beef cattle may improve beef quality by stabilizing it to oxidation. Lanari, Cassens, Schaefer, and Scheller (1994) reported that dietary vitamin E supplementation greatly increased lipid stability of frozen longissimus lumborum muscle. Lui, Scheller, Schaefer, Arp, and Williams (1994) also reported that lipid oxidation was slower in cooked gluteus medius from vitamin E-supplemented cattle than in that from control, unsupplemented cattle. Although enhancement and vitamin E supplementation may improve beef quality, it is important to understand what the consumer actually desires in beef quality. In a study involving European consumers, Glitsch (2000) reported that Italians rated the origin of the beef as the most important factor in evaluation of fresh meat quality prior to purchase, while Germans, Irish, and Swedes felt color was the dominant factor. Beef flavor, followed closely by tenderness, were most important to ‘‘eating quality.’’ The purpose of the present study was to evaluate the effects of enhancement and/or dietary vitamin E supplementation on consumer quality characteristics of beef, and to assess the attitudes of this consumer population towards fresh beef.
2. Materials and methods Paired beef rounds and strips from vitamin E-supplemented or unsupplemented cattle served as controls or were enhanced. Strip steak and round roast samples were evaluated by a consumer panel. Cook loss and shear force were also determined. Consumers voluntarily completed a beef attitude questionnaire following the beef sensory evaluation. 2.1. Animals and sample manufacture Twelve predominately Angus Hereford steers between 12 and 24 months of age were fed finishing diets at the Southern Illinois University Beef Research Unit, Carbondale, Ill. Animals were randomly assigned to either the vitamin E (E+) or no vitamin E (E ) treatment diets. Cattle assigned to the E+ treatment received diets formulated to provide at least 500 International Units (IU) of vitamin E, as dl-alpha tocopheryl acetate (Hoffman LaRoche, Basel, Switzerland) per day for the final 117 days of feeding. Fifteen days prior to harvest, supplementary vitamin E was withdrawn. Animals were harvested at the University of Illinois Meat
Science Laboratory abattoir. Carcasses were chilled (4 C, 24 h) then evaluated for USDA Quality grades (AMSA, 2001). The a-tocopherol content was determined on ground sirloin samples (13.8+2.7% fat) from each carcass by high performance liquid chromatography (Ralston Analytical, St. Louis, MO). Strip loins (IMPS 180; NAMP, 1997) and rounds (IMPS 169) were removed at 48 h postmortem. Cuts, labeled with animal identification and left/right side designation, were vacuum-packaged and held at 4 C. At 11 days’ postmortem, each of a cut pair was randomly assigned to the pumped (P) or control (C) treatment and pH was determined using a pH Star probe CPU (SSK Technology Inc., Cedar Rapids, IA). Enhanced loins and roasts were injected to 110% of raw weight to contain 0.4% sodium chloride and 0.4% sodium tripolyphosphate (sodium tripolyphosphate anhydrous, sodium polyphosphates, sodium hexametaphosphate, Rhodia Inc., Food Ingredients. Cranbury, NJ) on a finished weight basis. Pump solution (28 C, pH 7.90) was injected using a multiinjector system (Model N50, Wolf-tec, Inc., Kingston, NY). Following injection, cuts were placed into holding tubs, covered, and equilibrated at 4 C for 24 h. Inside round roasts and steaks were vacuum packaged (Multiva, AGW, Koch, Kansas City, MO), blast frozen ( 29 C) and held for 6 weeks. 2.2. Cooking methods Roasts and steaks were thawed at 4 C for a minimum of 48 h. Steaks were cooked to 70 C on a Farberware Open Hearth grill (Model 455N, Walter Kidde, Bronx, NY). Roasts were placed on baking racks and cooked in a convection oven (Model V15, South Bend Range Corporation, South Bend, IN) at 163 C to an internal temperature of 72 C. Internal temperature was monitored using copper-Constantin thermocouples (Type T, Omega Engineering, Stamford, CT) inserted into the geometric center and monitored with a Barnant scanning thermocouple thermometer (Model 692-8000, Barnant Co., Barrington, IL). 2.3. Consumer evaluation Potential panelists (n=112) were recruited from a database of consumers who have participated in previous sensory evaluation studies. Consumers were given appointments with 10 conducting evaluations during each 30-min session. Each consumer received four (E P, E+P, E C, E+C) steak samples (2.54 2.54 2.54 cm) followed by four (E P, E+P, E C, E+C) roast samples (2.54 2.54 2.54 cm) served individually in 30-ml plastic cups (Solo, Champaign, IL) labeled with three-digit random numbers. Sample presentation
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order was randomized from 10-member consumer group to group. Evaluation was accomplished using a 9-point hedonic scale. Following sample evaluation, consumers were asked to complete a questionnaire regarding their attitudes and expectations for beef (Fig. 1). Demographic data were also collected. Consumers were compensated for their time. 2.4. Warner–Bratzler shear One sample from each cut, from each treatment (enhancement vitamin E), from each animal (total=96 samples) was cooked as previously described. Cooked steaks and roasts were allowed to cool (25 C) for a minimum of 1 h. A slice (2.5 cm thick) was removed from the center of each roast. Four 1.3-cm cores were removed from each steak and from each roast slice parallel to the muscle fiber orientation. Shearing was accomplished with an Instron model 1122 Universal Testing Machine (Instron, Canton, MA) fitted with a Warner–Bratzler Shear attachment. The full scale load was 10 kg, while the chart drive and cross head speeds were 200 mm/min. The shear force values for the four cores were averaged for each sample. 2.5. Cook loss Raw and cooked weights of roasts and steaks were determined. Cook loss was calculated as: ([raw weight cooked weight]/raw weight) 100. 2.6. Statistical analysis Data were analyzed using a mixed model procedure (SAS, 2000) treating vitamin, enhancement treatment and their interaction as fixed effects. Vitamin treatment nested within animal was treated as a random effect. Means for significant (P < 0.05) effects were separated using probability of difference.
3. Results and discussion All carcasses graded high select (Se+, n=3) or low choice (Ch , n=9) (AMSA, 2001). The a-tocopherol content of ground sirloin samples from vitamin E supplemented steers (8.26+1.55 mcg a-tocopherol/g) was significantly (P < 0.0001) higher than that from the control, unsupplemented steers (2.67+0.62 mcg/g) indicating that the dietary regimen did, in fact, increase tissue vitamin E effects. Pump levels achieved were 9.47 and 9.42% for the rounds and strips, respectively. A total of 103 consumers evaluated the beef roasts and steaks and completed the questionnaire. About half were male and half were female (data not shown). Slightly over half (56%) were under 30 years of age. About 32% had a
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net family income < $20,000; > 43% had two people in the household. About half of this consumer group were the primary food purchaser in the household. The majority (> 80%) of respondents were Caucasian. 3.1. Effects of enhancement Enhancement had a major effect on the sensory quality of steaks and roasts (Table 1). Enhanced steaks and roasts were significantly more tender and juicy than controls. These results support those of trained sensory panel evaluations of enhanced beef (Robbins et al., 2002). In the present study, beef flavor, saltiness and overall acceptability were higher in the enhanced steaks and roasts than in their control counterparts. Warner– Bratzler shear values confirm the consumer-evaluated tenderness increase in that enhanced roasts had lower shear values (Table 1). Hoover et al. (1995) reported that consumers preferred beef strip loins injected with 200 mM CaCl2 solution at 5% (wt./wt.) to controls. Dhanda et al. (2001) also reported higher consumer tenderness, juiciness, flavor and overall acceptability for enhanced bison steaks compared to controls. In the present study, enhancement had no effect (P < 0.05) on cook loss of either roasts or steaks (Table 1). Significant enhancement by vitamin interactions show that E /enhanced steaks had the lowest shear value and highest tenderness, juiciness and overall acceptability scores (Figs. 2 and 3). In contrast, E+/control steaks had the highest shear force and lowest tenderness, juiciness and overall acceptability scores. The E+/control roasts were also least juicy (Fig. 3). The predominant effect appears to be due to enhancement, because, regardless of vitamin E treatment, enhanced steaks and roasts were more juicy and tender, had higher overall acceptability scores and lower shear force values than non-enhanced cuts. 3.2. Effects of vitamin E Supplementation of vitamin E into the diets of finishing steers had no positive effects on sensory scores of either the steaks or roasts and had no effect on cook loss (Table 2). Robbins et al. (2002) reported no vitamin E effects on trained sensory panel evaluations. In the present study, consumers found that steaks from unsupplemented cattle were more salty and had higher beef flavor scores than the E+ steaks. These findings were unexpected and the reason for them is unclear. Lanari et al. (1994) reported that dietary vitamin E had a major impact on lipid stability of frozen longissus lumborum muscle such that TBARS were less than 20% of those from controls. In the present study, TBARS were not determined, however the panel indicated that roasts and steaks were ‘‘neither unacceptable nor acceptable’’ to ‘‘moderately acceptable’’ suggesting that no or few off-flavors or
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Fig. 1. Beef attitude questionnaire.
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Fig. 1. (continued).
odors were present. In addition, roasts and steaks were vacuum packaged before freezing which significantly increases lipid stability. Vitamin E did not improve the quality of either the roasts or steaks. 3.3. Quality differences in various demographic groups Gender had no effect on any of the quality characteristics evaluated. Tenderness and overall acceptability of
roasts differed among the various education categories of consumers (Table 3). Consumers with a high school education or a graduate education rated roasts as more tender and acceptable than did those with some college or a college degree. It may be that consumers quality expectations relative to perceived product cost are weighted differently among these educational groups. Purchaser status affected a number of quality characteristics of roasts as well (Table 4). Those who shared the purchasing responsibility for food for the household
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Table 1 Enhancement effects on consumer characteristics beef steaks and roastsa Characteristic
Enhanced
Control
P value
S.E.M.b
Steaks Tendernessc Juicinessc Beef flavor Saltiness Overall acceptabilityc Shear forcec % Cook loss
7.46 7.29 7.65a 7.02a 7.48 1.16 24.95
6.58 6.55 6.46 b 6.09 b 6.51 2.26 22.68
<0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 0.25
0.13 0.14 0.13 0.13 0.12 0.16 1.13
Roasts Tenderness Juiciness Beef flavor Saltiness Overall acceptability Shear force % Cook loss
6.18a 5.24a 6.71a 6.22a 6.16a 2.47b 35.30
5.05 4.72 5.85 5.55 5.27 3.24 36.66
b b b b b a
<0.0001 0.0096 <0.0001 0.0001 <0.0001 <0.0001 0.33
0.24 0.29 0.13 0.13 0.20 0.14 1.56
a
Means in the same row with like letters do not differ. Standard error of the means. c A significant enhancement vitamin E interaction existed for this characteristic. b
found roasts to be less juicy, beef flavored, salty and overall acceptable than did those who had the primary purchasing responsibility. However, those who were not the primary purchasers of food were a much smaller group (8.7%) than those who shared responsibility (38.8%) or who were primary purchasers of food (52.5%). If we consider only those who purchase or share in purchase responsibility, it may be that those who share the
Table 2 Dietary vitamin E supplementation effects on consumer characteristics of beef steaks and roastsa Characteristic
E+
E
P value
S.E.M.b
Steaks
Tendernessc Juicinessc Beef flavor Saltiness Overall acceptabilityc Shear force, kgc Cook loss, %
6.67 6.68 6.82b 6.34b 6.72 2.10 24.95
7.37 7.15 7.29a 6.76a 7.27 1.77 22.68
0.0066 0.0543 0.0495 0.0400 0.0104 0.18 0.27
0.15 0.16 0.15 0.13 0.13 0.16 1.13
Roasts
Tenderness Juiciness Beef flavor Saltiness Overall acceptability Shear force, kg Cook loss, %
5.46 4.89 6.12 5.76 5.54 3.12 36.48
5.77 5.07 6.44 6.01 5.90 2.59 35.48
0.4846 0.7495 0.1292 0.2427 0.3421 0.18 0.65
0.30 0.38 0.14 0.14 0.25 0.14 1.56
a
Means in the same row with like letters do not differ. Standard error of the means. c A significant enhancement vitamin E interaction existed for this characteristic. b
responsibility are less attentive to product characteristics. Household size had a significant effect on some characteristics of steaks (Table 5). In general, consumers with 54 people in the household found steaks to be more beefy flavored, salty and overall acceptable than did consumers from 2-person households. It may be that those consumers with fewer people in the household are less attentive, in general, to food quality characteristics.
Fig. 2. Enhancement by vitamin E effects on shear force of steaks.
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Fig. 3. Enhancement by vitamin E effects on consumer sensory evaluation of steaks.
3.4. Consumer attitudes Based on responses to the beef attitude questionnaire, consumers felt that an optimal steak should be somewhat marbled (mean=8.7; 15=high) and moderately bright red (5.9; 15=dark red). They were somewhat concerned about added ingredients (8.1; 15=highly concerned) (data not shown). In terms of consumption characteristics, consumers reported that an optimal steak should be very tender (12.6) and juicy (12.8), and have intense beef flavor (12.1); amount of liquid on the plate was less of a concern (8.0). On a 10-point scale, with more points assigned to factors of greater importance, consumers felt that, when making purchasing decisions for fresh prepackaged steaks, the cut (mean=7.6), color (7.5), visible fat (7.1), price (6.9), and amount of liquid in the package (6.6) were the most important factors to consider (data not shown). Glitsch (2000) reported that color was among the most important factors when European consumers Table 3 Consumer educational level effects on quality characteristics of roasts derived from cattle receiving vitamin E supplementationa High Some College Graduate P value school college graduate school Tenderness 5.26a Overall acceptability 6.40a a
4.92ab 4.30b 5.38b 5.23b
5.30a 6.03ab
Means in the same row with like letters do not differ.
0.02 0.01
considered purchasing fresh meat. Carpenter, Cornforth, and Whittier (2001) also reported that the red color of beef was preferred and what consumers look for when purchasing beef. Brewer, Zhu, and McKeith (2001) reported that purchase intent of fresh pork chops paralleled lean appearance and acceptability. Consumers Table 4 Purchaser status effects on consumer sensory characteristics of roasts derived from cattle receiving vitamin E supplementationa Primary Share Not P value purchaser purchasing primary of food responsibility purchaser Tenderness Juiciness Beef flavor Saltiness Overall acceptability a
5.94a 5.27a 6.59a 6.11a 6.08a
5.67ab 4.41b 5.86b 5.44b 5.18b
5.16b 5.78a 6.42a 6.47a 5.92a
0.001 <0.001 0.001 0.001 0.001
Means in the same row with like letters do not differ.
Table 5 Household size status effects on consumer sensory characteristics of steaks derived from cattle receiving vitamin E supplementationa
Beef flavor Saltiness Overall acceptability a
1 person
2 people
3 people
54 people
P value
6.87b 6.76ab 6.97ab
6.87b 6.28b 6.81b
7.22ab 6.60ab 7.18ab
7.57a 6.92a 7.32a
0.0025 0.0265 0.05
Means in the same row with like letters do not differ.
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expressed a higher degree of purchase intent for leaner pork, but found that more marbled pork produced greater eating satisfaction when consumed in a laboratory setting. Added visible fat was a consumer concern in that study as well. In the present study, the servings/ package (5.1), a sale or promotion (5.8) and added ingredients (5.8) were of secondary concern; the store (4.4) and the brand (3.2) had less impact on consumer decision to purchase steaks. Tenderness, juiciness and flavor (12.6, 12.8, and 12.1, respectively, on a 15-point scale) contributed the most to satisfaction when consuming steaks. These results agree with those of Glitsch (2000) who found tenderness and flavor to be the most important factors in ‘‘eating quality’’ of Europeans. In the present study, beef flavor, degree of doneness and total satisfaction with the product were also given more weight in consumers’ expected satisfaction. The National Cattlemen’s Beef Association (2001) also found flavor to be the key factor driving customer satisfaction. Based on their perception of an ‘‘ideal’’ steak, consumers were asked to assign 0–100 points to their average experienced satisfaction with prepackaged steaks purchased at the supermarket. The sample population in this study gave a score of 69.1 for average purchasing satisfaction and 65.5 for average eating satisfaction (data not shown). The average purchasing and eating satisfaction based on consumer perception of an ‘‘ideal’’ beef steak suggests that the beef industry could still make improvements to increase consumer satisfaction. The 2001 Beef Customer Satisfaction study (National Cattlemen’s Beef Association, 2001) suggests that satisfaction ratings could be increased by selecting top choice and select cuts and by more closely monitoring degree of doneness for various steaks. In the current study, the important factors were tenderness and juiciness, both of which are related to quality grade and degree of doneness. Enhancement increased both tenderness and juiciness. In addition, Prestat et al. (2002) and Jensen et al. (2002) reported that enhancement ‘‘protects’’ pork from the ravages of overcooking. Overall, enhancement may allow lower quality grades and higher degrees of doneness to be tolerable without sacrificing consumer satisfaction.
4. Summary Enhancement significantly increased the consumer acceptability of beef steaks and roasts. However, dietary vitamin E supplementation had no effect on consumer characteristics of either. Consumers reported that color, visible fat, price and cut were the most important factors they considered when purchasing. Tenderness, flavor and juiciness, significantly increased by enhancement, were found to be the most important factors with
respect to consumers eating satisfaction. Although some concern was expressed regarding added ingredients in beef steaks, enhancement has the potential to effectively increase tenderness and juiciness of beef roasts and steaks.
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