This is an open access article distributed under the CC BY-NC-ND license (
Paired USDA Choice top sirloin butts (
The beef top sirloin steak is an important foodservice cut due to its demand by cost-concerned consumers. Yet, in comparison to steaks from the rib and loin, the top sirloin often fails in delivering consistent and satisfactory eating experiences to foodservice clientele, which is an important fact to consider since consumers view tenderness as the most important organoleptic characteristic of meat (
To combat shortcomings inherent to the sirloin, a variety of processes have traditionally been implemented to increase consumer acceptability. The benefits of using blade tenderization to enhance tenderness are known (
The objectives of this study were: 1) to determine if consumer satisfaction improves by blade tenderizing today’s more inherently tender beef, 2) to evaluate the use of freezing of top sirloin butts during the subprimal storage period to see if it will enhance tenderness of steaks, and 3) to assess whether a short aging period for top sirloin butts would produce steaks of the same quality when compared to those from top sirloin butts aged for the traditional extended periods.
Consumer panel procedures were approved by the Texas A&M Institutional Review Board for Use of Humans in Research (IRB2016–0227M).
Paired USDA Choice beef loin, top sirloin butt, semi center-cut, boneless subprimals (
After fabrication, subprimals were labeled, vacuum packaged individually, boxed, and shipped under refrigeration to a collaborating beef purveyor. Paired subprimals were divided equally among 3 trials: 1) blade tenderized (BT) vs. non-blade tenderized (NBT) treatments, 2) refrigeration vs. frozen aging, and 3) 14-d vs. 35-d refrigerated aging. For all trials, aging periods began the day of subprimal fabrication, which occurred 2 d postmortem.
Ten paired top sirloin butts (
Ten paired top sirloin butts (
Ten paired top sirloin butts (
After treatment application, a Grasselli (NSL 800, Albinea, Italy) slicer was used to generate 5 2.5-cm-thick portions from each subprimal by cutting dorsal to ventral (approximately perpendicular to the muscle fibers) with the third portion being from the middle of the subprimal. Portions were identified as 1, 2, 3, 4, and 5, cranial to caudal. Only portions 2 and 3 were used in this study. These portions were cut into thirds to produce 3 steaks (2.5-cm thick from the initial slicing), which were identified as Steaks A, B, and C from portion 2, and Steaks D, E, and F from portion 3. These steaks were hand-trimmed to produce steaks that weighed approximately 170 g. To reduce inherent location effects, steaks from the same anatomical location from each these portions were used for sensory and for WBS force evaluations, respectively. Steak A was used for Warner-Bratzler Shear (WBS) force, Steaks B, C, D, and E were used for consumer sensory panels, and Steak F was held in reserve.
Steaks were labeled and vacuum packaged individually with a rollstock machine (Multivac R150; Kansas City, MO) using Sealed Air, Food Care Division (Charlotte, NC) Item No. T7230B 3.0 mil top web with an Oxygen Transmission Rate (OTR) 4 [cc/m2 per d at 23°C, 0% R.H] and Item No. T7045B 4.5 mil bottom web with an OTR of 3 [cc/m2 per d t 23°C, 0% R.H]. Steaks then were boxed and placed into plastic insulated containers with refrigerated materials and transported to Texas A&M University (College Station, Texas). Upon arrival, steaks were stored under refrigerated conditions (∼ 0°C) until subsequent analyses; steaks for trial 3 were flash frozen (–40°C) after packaging, then stored frozen (∼ –23°C) and later thawed for testing.
Steaks for consumer sensory analysis and WBS force were cooked in the same manner. For Trials 1 and 2, cooking was completed within 3 d of the steaks arriving in College Station. For Trial 3, frozen steaks were thawed under refrigerated conditions (∼ 0°C) for 48 h before cooking. All steaks were cooked on a Star International commercial flat-top grill (Max Model 536TGF, St. Louis, MO). The grill was preheated to 176°C ± 2°C, with internal steak temperatures monitored using thermocouple readers (Model HH506A; Omega Engineering, Stanford, CT) and 0.02 cm diameter copper-constantan Type-T thermocouple wire (Omega Engineering) inserted into the geometric center of each steak. Steaks were cooked to 35°C, flipped, and cooked to a final endpoint temperature of 70°C. Raw out of package weight, initial internal temperature, grill temperature, final internal temperature, cook time, final cook weight, and cook loss were all collected on each steak (
Paired t-tests for weights, steak temperatures, cook loss, grill temperature, and cook duration of sensory and Warner-Bratzler shear force steaks from subprimals that were blade tenderized versus not blade tenderized
Treatment | n | Raw weight, g | Raw internal temperature, °C | Cooked weight, g | Cooked internal temperature, °C | Cook loss, % | Grill surface temperature, °C | Cook duration, min |
BT | 10 | 177.7 | 11.2 | 133.6 | 70.1 | 24.9 | 177.1 | 18.9 |
NBT | 10 | 171.2 | 10.9 | 129.8 | 70.1 | 24.1 | 177.1 | 18.9 |
SE | 1.43 | 0.08 | 1.76 | 0.07 | 0.59 | 0.35 | 0.75 | |
Prob > t | 0.9993 | 0.9980 | 0.0304 | 0.3860 | 0.8849 | 0.5393 | 0.5923 |
Treatment: BT = top sirloin butts were run once through a blade tenderizer before cutting into steaks; NBT = top sirloin butts were not blade tenderized before cutting into steaks.
Number of subprimals evaluated.
Paired t-tests for weights, steak temperatures, cook loss, grill temperature, and cook duration of sensory and Warner-Bratzler shear force steaks from subprimals that were refrigerated versus frozen during aging
Treatment | n | Raw weight, g | Raw internal temperature, °C | Cooked weight, g | Cooked internal temperature, °C | Cook loss, % | Grill surface temperature, °C | Cook duration, min |
Refrigerated | 10 | 179.9 | 12.0 | 137.0 | 70.2 | 23.8 | 177.2 | 20.3 |
Frozen | 10 | 170.0 | 12.4 | 128.7 | 70.0 | 24.4 | 176.8 | 17.6 |
SE | 3.14 | 0.16 | 2.73 | 0.08 | 0.59 | 0.33 | 0.60 | |
Prob > t | 0.0059 | 0.9678 | 0.0073 | 0.0436 | 0.8081 | 0.8525 | 0.9993 |
Treatment: Refrigerated = top sirloin butts were aged under refrigeration for 35 d before cutting into steaks; Frozen = top sirloin butts were aged under refrigeration for 14 d, frozen for 14 d, and then placed back in refrigeration for 7 d before cutting into steaks.
Number of subprimals evaluated.
Paired t-tests for weights, steak temperatures, cook loss, grill temperature, and cook duration of sensory and Warner-Bratzler shear force steaks from subprimals that were aged for 14- versus 35 d
Treatment | n | Raw weight, g | Raw internal temperature, °C | Cooked weight, g | Cooked internal temperature, °C | Cook loss, % | Grill surface temperature, °C | Cook duration, min |
14 d | 10 | 169.6 | 13.6 | 128.6 | 70.1 | 24.1 | 176.5 | 16.9 |
35 d | 10 | 166.0 | 13.2 | 124.9 | 70.1 | 24.8 | 176.6 | 17.1 |
SE | 4.60 | 0.35 | 3.40 | 0.04 | 0.92 | 0.24 | 0.66 | |
Prob > t | 0.7782 | 0.8637 | 0.8542 | 0.3484 | 0.2242 | 0.2700 | 0.2901 |
Treatment: 14 d = top sirloin butts were aged for 14 d under refrigeration before cutting into steaks; 35 d = top sirloin butts were aged for 35 d under refrigeration before cutting into steaks.
Number of subprimals evaluated.
Consumer panelists (
Demographic summary of consumer panelists (
Item | n | % | |||
Gender | |||||
Male | 131 | 55 | |||
Female | 109 | 45 | |||
Age | |||||
20 yr or younger | 15 | 6 | |||
21 - 25 yr | 75 | 31 | |||
26 - 35 yr | 60 | 25 | |||
36 - 45 yr | 22 | 9 | |||
46 - 55 yr | 27 | 11 | |||
56 - 65 yr | 24 | 10 | |||
66 yr and older | 17 | 7 | |||
Working status | |||||
Not employed | 20 | 8 | |||
Part-time | 39 | 15 | |||
Full-time | 103 | 40 | |||
Student | 93 | 37 | |||
Annual household income | |||||
$100,000 or more | 56 | 23 | |||
$75,000 - 99,999 | 30 | 13 | |||
$50,000 - 74,999 | 34 | 14 | |||
$25,001 - 49,999 | 39 | 16 | |||
Below $25,000 | 81 | 34 | |||
Dietary restrictions | |||||
No | 226 | 94 | |||
Yes | 14 | 6 | |||
Self/Immediate family works for a food company | |||||
No | 237 | 99 | |||
Yes | 3 | 1 | |||
Ethnic background | |||||
White | 198 | 83 | |||
Hispanic | 20 | 8 | |||
Asian or Pacific Islander | 9 | 4 | |||
Black | 8 | 3 | |||
Other | 4 | 2 |
No. of responses.
Consumer panelists’ consumption patterns (
Item | n | % | ||
Meat consumption | ||||
Yes | 240 | 100 | ||
Type of meat consumed | ||||
Beef | 240 | 100 | ||
Chicken | 239 | 99 | ||
Fish | 209 | 87 | ||
Pork | 231 | 96 | ||
Frequency of beef consumption | ||||
Daily | 19 | 8 | ||
5 or more times per wk | 50 | 21 | ||
3 or more times per wk | 114 | 48 | ||
Once per wk/weekly | 49 | 20 | ||
Once every 2 weeks | 6 | 2 | ||
Less than once every 2 wk | 2 | 1 | ||
Frequency of beef consumed at home per wk | ||||
0 | 12 | 5 | ||
1 | 55 | 23 | ||
2 | 80 | 34 | ||
3 | 56 | 24 | ||
4 | 24 | 10 | ||
5 | 3 | 1 | ||
5+ | 8 | 3 | ||
Frequency of beef consumed at restaurant per wk | ||||
0 | 9 | 4 | ||
1 | 102 | 43 | ||
2 | 70 | 29 | ||
3 | 31 | 13 | ||
4 | 15 | 6 | ||
5 | 5 | 2 | ||
5+ | 7 | 3 | ||
Preferred degree of doneness | ||||
Rare | 8 | 3 | ||
Medium rare | 79 | 32 | ||
Medium | 5 | 2 | ||
Medium well | 106 | 43 | ||
Well done | 51 | 20 | ||
Type of beef purchased | ||||
Aged | 26 | 9 | ||
Grass-fed | 29 | 10 | ||
Organic | 18 | 6 | ||
Traditional | 213 | 75 |
No. of responses.
Panelists were provided with Nabisco Unsalted Tops Premium Saltine Crackers (Kraft Foods Global, Inc., East Hanover, NJ) and double-distilled, deionized water to use as palate cleansers between each sample. Serving order was randomized for each group to eliminate first-order bias. Samples were served through individual breadbox-style sensory booths equipped with red theater lighting to prevent panelist bias for degree of doneness. Panelists evaluated samples using 9-point scales (1 = dislike extremely; 9 = like extremely) for overall liking, flavor liking, tenderness liking, and juiciness liking.
Following the cooler storage period, steaks were allowed to equilibrate to room temperature before being trimmed of visible connective tissue to expose muscle fiber orientation. Using a hand-held coring device, six 1.3-cm cores were removed from each
Microsoft Excel (Microsoft Corporation, Redmond, WA) was used to calculate frequencies for consumer panelists’ demographics. Trial data were analyzed separately with paired
Paired
Paired t-tests for sensory panel ratings and Warner-Bratzler shear force values for steaks from subprimals that were blade tenderized versus not blade tenderized
Treatment | n | Sensory panel ratings | Warner-Bratzler shear force, N | |||
Overall like/dislike | Tenderness like/dislike | Flavor like/dislike | Juiciness like/dislike | |||
BT | 10 | 6.7 | 6.7 | 6.7 | 6.4 | 26.4 |
NBT | 10 | 6.3 | 6.0 | 6.5 | 6.1 | 28.2 |
SE | 0.14 | 0.15 | 0.08 | 0.20 | 2.29 | |
Prob > t | 0.0293 | 0.0011 | 0.0198 | 0.1138 | 0.4395 |
Treatment: BT = top sirloin butts were run once through a blade tenderizer before cutting into steaks; NBT = top sirloin butts were not blade tenderized before cutting into steaks.
Number of subprimals per treatment.
Sensory panel ratings: 9 = like extremely; 1 = dislike extremely.
Connective tissue is a dominant factor affecting meat tenderness, with
Combined with the location on the carcass causing a relative lack of stretching, fiber type helps to explain why the top sirloin traditionally records shorter sarcomere lengths compared to other cuts in the loin (
There were no differences in sensory panel ratings (
Paired t-tests for sensory panel ratings and Warner-Bratzler shear force values for steaks from subprimals that were refrigerated versus frozen during aging
Treatment | n | Sensory panel ratings | Warner-Bratzler shear force, N | |||
Overall like/dislike | Tenderness like/dislike | Flavor like/dislike | Juiciness like/dislike | |||
Refrigerated | 10 | 6.3 | 6.0 | 6.4 | 5.8 | 26.7 |
Frozen | 10 | 6.1 | 5.8 | 6.2 | 6.1 | 30.7 |
SE | 0.14 | 0.21 | 0.11 | 0.26 | 1.97 | |
Prob > t | 0.0946 | 0.3017 | 0.1005 | 0.2870 | 0.0733 |
Treatment: Refrigerated = top sirloin butts were aged under refrigeration for 35 d before cutting into steaks; Frozen = top sirloin butts were aged under refrigeration for 14 d, frozen for 14 d, and then placed back in refrigeration for 7 d before cutting into steaks.
Number of subprimals per treatment.
Sensory panel ratings: 9 = like extremely; 1 = dislike extremely.
The use of freezing as a method to enhance tenderness and extend shelf life has long been a topic of interest in industry. It is known that freezing meat is advantageous in that it preserves product longer than fresh storage; however, freezing also increases drip loss and causes ultrastructural changes in the muscle fiber (
Research conducted observing the effects of freezing on a variety of muscles on meat quality has produced varying results in relation to tenderness (
When considering the impact of freezing on consumer perception,
In the current study, it was not known if freezing and thawing of the top sirloin subprimal would provide the same tenderness benefits as those seen with individual steaks (
Across the industry, use of extended aging periods has been historically used as a method to enhance tenderness by altering the myofibrillar structure postmortem.Yet, previous research has shown that combining practices could potentially be more beneficial than relying on aging alone. This is likely due to the further alteration of tenderness factors such as connective tissue and sarcomere length through additional practices such as blade tenderization or carcass suspension.
Paired t-tests for sensory panel ratings and Warner-Bratzler shear force values for steaks from subprimals that were aged for 14 versus 35 d
Treatment | n | Sensory panel ratings | Warner-Bratzler shear force, N | |||
Overall like/dislike | Tenderness like/dislike | Flavor like/dislike | Juiciness like/dislike | |||
14 d | 10 | 6.0 | 5.6 | 6.3 | 5.6 | 30.7 |
35 d | 10 | 6.1 | 6.0 | 6.1 | 5.9 | 27.5 |
SE | 0.25 | 0.29 | 0.20 | 0.28 | 1.81 | |
Prob > t | 0.6321 | 0.1868 | 0.3795 | 0.2948 | 0.1215 |
Treatment: 14 d = top sirloin butts were aged for 14 d under refrigeration before cutting into steaks; 35 d = top sirloin butts were aged for 35 d under refrigeration before cutting into steaks.
Number of subprimals per treatment.
Sensory panel ratings: 9 = like extremely; 1 = dislike extremely.
Extended aging periods work to disrupt the integrity of the myofibrils through proteolysis (
It is clear from the present study that up to 35 d of aging does not result in improved palatability or WBS force values of the top sirloin when compared to those subprimals aged for 14 d. Because the top sirloin does not respond to aging like other rib and loin cuts, our knowledge of the aging practices used by most purveyors is that they employ extended-aging times as a way to ensure tenderness. Based on these findings, there is no benefit to extending the aging periods for the top sirloin, thus providing the industry with potential evidence to decrease storage times and expedite shipping to increase product availability.
Today’s inherently tender beef has been a benefit to the industry, and because of this, traditional practices of postmortem aging, blade tenderization, and freezing needed to be revisited to ensure that their benefits are still worthwhile. This study showed that longer aging periods (e.g., up to 35 d) are not needed for top sirloin butts, as shorter aging periods (e.g., 14 d) produced steaks of comparable sensory and WBS force characteristics. These findings allow purveyors flexibility in utilizing shorter product storage periods without sacrificing meat tenderness or quality.
Our work showed no objective or subjective differences in comparing beef aged under refrigerated versus frozen conditions. Freezing and thawing of top sirloin butts compared to only aging them under refrigeration achieved similar and interchangeable palatability characteristics between steaks. These findings offer purveyors, retail, and foodservice establishments options in how top sirloin butts are handled before cutting into steaks, alleviating the concern of detrimental consumer perceptions due to freezing.
Finally, blade tenderization did improve sensory panel ratings for overall and tenderness liking compared to the non-blade tenderized controls. Although WBS force values were similar between treatments, improvements in sensory panel ratings with blade tenderization show that this common method of enhancing tenderness is still beneficial for the top sirloin steak.