Evaluation of Beef Palatability Following Extended Storage at Low Temperature

Introduction

With a fast-growing world population and increasing food demand, food systems must undergo transformations to ensure food security while complying with environmental, economic, and social objectives to meet global sustainability goals (Godfray et al., 2010; FAO, 2018). Extending the shelf life of fresh meat without any adverse effect on quality attributes is critically important to the meat industry to stabilize supply and facilitate export shipments. Meat is commonly preserved by storing it at chilled temperatures (2°C to 4°C). However, its shelf life under regular chilling conditions can be limited (on average 8 to 10 wk under vacuum packaging) primarily due to microbial spoilage (Coombs et al., 2017; Lu et al., 2019). Previous research has shown that the shelf life of fresh beef can be increased to up to 20 wk (140 d) when the product is vacuum-packaged and stored below regular chilling temperatures (around −0.5°C to −1.5°C) (Small et al., 2012; Chen et al., 2019). Furthermore, extended refrigerated storage/aging times can improve beef tenderness through the breakdown of muscle proteins by endogenous proteolytic enzymes (Casas et al., 2006; Ramanathan et al., 2020).

The 2015 National Beef Tenderness Survey reported that the average length of aging for steaks in retail and food service settings was 25.9 and 31.5 d, respectively (with a range of 3 to 102 d), and 11% of the steaks had less than 14 d of aging (Martinez et al., 2017). Such a variation in postmortem aging time could lead to inconsistency in tenderness between products (Dixon et al., 2012; Marino et al., 2013; Nair et al., 2019). In addition, during the peak steak consumption times of the year in the US, such as summer (Lusk et al., 2001; USDA-ERS, 2022), not all retailers and restaurants might have the supply of tender steaks needed to meet the demand, which could result in the use of steaks with low postmortem aging days or frozen beef. Additionally, beef market prices are seasonal and become highly inelastic during the summer months (Lusk et al., 2001), as consumers are willing to pay a higher price for specific cuts (Ardeshiri et al., 2019). Even when frozen beef can be used to stabilize the supply during the peak demand periods of the year, negative quality attributes associated with frozen beef, such as high purge, low color stability, poor tenderness, and high off-flavors, need to be considered (Wheeler et al., 1990; Lu et al., 2019; Wang et al., 2020).

Low temperature (LT) storage of beef subprimals slightly above their freezing point without the formation of ice crystals could slow down the growth of spoilage microflora and continue postmortem tenderization while maintaining the product’s fresh status. This enables beef buyers to have a product held for weeks or even months (≤3 mo) delivered to them equivalent to a fresh product in terms of storage temperature. Previous studies have shown that extended postmortem aging of samples for more than 42 d can adversely affect beef flavor (Juárez et al., 2010; Garmyn et al., 2020; Karney et al., 2022). Nevertheless, research on the palatability characteristics of beef following LT extended storage is limited. Therefore, the objective of this study was to evaluate tenderness and palatability characteristics of beef inside round (IR), bone-in ribeye (RE), and striploin (SL) cuts following 60, 75, and 90 d of LT storage.

Materials and Methods

Results

Cooking loss

The percentage of cooking loss by cut and storage days is shown in Figure 1. The different storage conditions (i.e., LT or 21 d wet-aged) and times had no effect (P ≥ 0.05) on cooking loss irrespective of subprimal cut.

Figure 1.

Effect of low temperature (−2.7°C ± 0.3°C) storage times (60, 75, or 90 d) or 21 d of wet aging on the percentage of cooking loss of inside round (IR), bone-in ribeye (RE), and striploin (SL) steaks (n = 10). Same letters (a) above the error bars indicate similarity (P ≥ 0.05). Error bars represent the standard error of the mean.

Warner-Bratzler shear force

The WBSF values of all 3 cuts generally decreased with an increase in storage time, as shown in Figure 2. However, WBSF values of LT60 steaks were similar (P ≥ 0.05) to the control steaks subjected to 21 d of wet aging, regardless of the cut. WBSF values for LT90 RE and SL steaks were lower (P < 0.05) than their corresponding LT60 and 21 d wet-aged samples. For IR, LT75 and LT90 samples had lower (P < 0.05) WBSF values than steaks subjected to 21 d of wet aging but were similar (P ≥ 0.05) to those of LT60 steaks.

Figure 2.

Effect of low temperature (−2.7°C ± 0.3°C) storage times (60, 75, or 90 d) or 21 d of wet aging on Warner-Bratzler shear force (kg) of inside round (IR), bone-in ribeye (RE), and striploin (SL) steaks (n = 10). Different letters (a-b) above the error bars indicate significant differences (P < 0.05). Error bars represent the standard error of the mean.

Sensory evaluation

Consumer sensory ratings for juiciness, tenderness, flavor, and overall liking are presented in Figures 3, 4, and 5 for IR, RE, and SL, respectively, and the percentage of acceptance of these sensory traits and absence of off-flavor for all cuts are shown in Table 1. As presented in Figure 3, IR sample scores for juiciness, flavor, and overall liking were similar (P ≥ 0.05) between the storage conditions and days. Tenderness scores for IR LT75 steaks were higher (P < 0.05) than those of 21 d wet-aged samples but were not different (P ≥ 0.05) from the tenderness scores of LT60 and LT90 steaks (Figure 3B). The overall liking scores of all IR samples were similar (P ≥ 0.05; Figure 3D). Additionally, all the sensory traits’ acceptance percentages were similar (P ≥ 0.05) for IR steaks within storage conditions and days (Table 1). However, tenderness of LT75 steaks had a percentage acceptability of 92.3% (P = 0.1), which is at least 7% higher than the rest of the treatments. This result for the IR steaks follows the same pattern as the tenderness score, where LT75 steaks had the highest tenderness rating.

Figure 3.

Consumer panelists (N = 79) sensory evaluation of inside round steaks (IR; n = 10) that were in low temperature (−2.7°C ± 0.3°C) storage (60, 75, or 90 d) or were wet-aged for 21 d. A: juiciness with a scoring scale from 0 to 100 was used, with 0 being labeled as extremely dry, 50 neither juicy nor dry, and 100 extremely juicy; B: tenderness with a scoring scale from 0 to 100 was used, with 0 being labeled as extremely tough, 50 neither tough nor tender, and 100 extremely tender; C: flavor liking; D: overall liking using scoring scale from 0 to 100 with 0 being labeled as dislike extremely, 50 neither like nor dislike, and 100 like extremely. Different letters (a-b) above the error bars indicate significant differences (P < 0.05). Error bars represent the standard error of the mean.

Figure 4.

Consumer panelists (N = 79) sensory evaluation of ribeye steaks (RE; n = 10) that were in low temperature (−2.7°C ± 0.3°C) storage (60, 75, or 90 d) or were wet-aged for 21 d. A: juiciness with a scoring scale from 0 to 100 was used, with 0 being labeled as extremely dry, 50 neither juicy nor dry, and 100 extremely juicy; B: tenderness using a scoring scale from 0 to 100 was used with 0 being labeled as extremely tough, 50 neither tough nor tender, and 100 extremely tender; C: flavor liking; D: overall liking using scoring scale from 0 to 100 was used with 0 being labeled as dislike extremely, 50 neither like nor dislike, and 100 like extremely. Same letters (a) above the error bars indicate similarity (P ≥ 0.05). Error bars represent the standard error of the mean.

Figure 5.

Consumer panelists (N = 80) sensory evaluation of striploin steaks (SL; n = 10) that were in low temperature (−2.7°C ± 0.3°C) storage (60, 75, or 90 d) or were wet-aged for 21 d. A: juiciness with a scoring scale from 0 to 100 was used, with 0 being labeled as extremely dry, 50 neither juicy nor dry, and 100 extremely juicy; B: tenderness using a scoring scale from 0 to 100 was used with 0 being labeled as extremely tough, 50 neither tough nor tender, and 100 extremely tender; C: flavor liking; D: overall liking using scoring scale from 0 to 100 was used with 0 being labeled as dislike extremely, 50 neither like nor dislike, and 100 like extremely. Different letters (a-b) above the error bars indicate significant differences (P < 0.05). Error bars represent the standard error of the mean.

The results of the consumer sensory evaluation of the RE steaks are shown in Figure 4. Consumers could not detect (P ≥ 0.05) any difference in the sensory attributes of RE steaks, regardless of the storage time (Figure 4). Likewise, there were no differences (P ≥ 0.05) in the absence of off-flavor and acceptability for juiciness, tenderness, flavor, and overall liking within each storage period (Table 1). As expected, the tenderness acceptability percentage of RE steaks was higher than 91%, regardless of the storage time (Table 1).

For the SL samples, there was no (P ≥ 0.05) storage time effect on juiciness, flavor, and overall liking (Figure 5). However, consumers detected differences among the storage times for tenderness ratings of SL steaks. More specifically, tenderness scores of LT90 samples were greater (P < 0.05) than those of LT60 steaks but similar (P ≥ 0.05) to tenderness scores of LT75 and 21 d wet-aged samples. Additionally, percentages of acceptance of all sensory traits evaluated and the absence of off-flavor on SL steaks did not (P ≥ 0.05) differ by storage time (Table 1).

Discussion

Previous research has demonstrated that storage of beef below typical chilling temperatures (−0.5°C to −1.5°C) can extend its shelf life by up to 20 wk (Small et al., 2012; Chen et al., 2019; Yang et al., 2022). Beef quality attributes such as WBSF, cooking loss, and color, following storage at temperatures below 0°C without freezing have been evaluated previously (Chen et al., 2019; Lu et al., 2019, 2020; Yang et al., 2022; Zhang et al., 2023). These studies have demonstrated that storage of vacuum-packaged beef below typical chilling temperatures can extend its shelf life while improving postmortem tenderization. However, the effect of this extended storage on palatability traits has not been examined extensively. Palatability traits such as tenderness, juiciness, and flavor are critical for consumer acceptance and repurchase decisions (Smith and Carpenter, 1974; Lyford et al., 2010). In the current study, palatability characteristics, including cooking loss, WBSF, and sensory evaluations of 3 major beef cuts (IR, RE, and SL) following LT storage, were assessed. In general, as storage time increased, WBSF values decreased, and tenderness rating increased, with no differences in cooking loss or juiciness, flavor, and overall liking.

Most of the weight loss that occurs during cooking is the result of water being expelled by protein degradation and muscle fiber contraction (Lepetit et al., 2000; Kondjoyan et al., 2013; Hughes et al., 2014). With extended storage time, a decrease in water holding capacity is expected, which can lead to an increase in cooking loss. However, in the current study, the storage condition and time did not influence the cooking loss of the IR, RE, and SL steaks (Figure 1). Cao et al. (2022) evaluated the cooking loss of beef longissimus dorsi steaks at 0, 4, 8, 12, 16, 20, and 24 d of vacuum storage at refrigerated (4°C) and superchilled temperatures (−1.5°C). These researchers reported that following storage, samples stored at 4°C had higher cooking loss than samples held at −1.5°C for the same length of time (Cao et al., 2022). Interestingly, under both storage conditions, cooking loss initially increased from 0 to 4 d and then decreased during the remainder of the storage time (Cao et al., 2022). In contrast, Lu et al. (2019) assessed the effect of extended storage at −4°C (0 to 24 wk) and 2°C (0 to 8 wk) on SL. Samples stored at −4°C had greater cooking loss than those held at 2°C (Lu et al., 2019). However, cooking loss of samples held at −4°C for 8, 12, and 24 wk was similar, suggesting that changes in cooking loss might not be significant after 8 wk (56 d) of storage (Lu et al., 2019).

Tenderness is considered the most critical factor in overall eating satisfaction and consumers’ acceptability of beef (Miller et al., 2001; Shackelford et al., 2001). In the present study, WBSF values of all 3 cuts decrease with an increase in storage time, as shown in Figure 2. In general, initial tenderness (21 d wet-aged) for all the cuts met the Minimum Tenderness Threshold Value of less than 4.4 kg WBSF (ASTM, 2011). Furthermore, WBSF values of RE and SL steaks after 21 d of wet aging could be considered “very tender” (ASTM, 2011), and WBSF values of IR steaks achieved this threshold after LT60. The WBSF results of this study agree with previous studies that have observed a decrease in shear force with an increase in aging time (Gruber et al., 2006; Dixon et al., 2012; Colle et al., 2015; Karney et al., 2022). However, the results can vary depending on parameters such as storage temperature and muscle evaluated (Lu et al., 2019; Nair et al., 2019; Lu et al., 2020). For example, Lu et al. (2019) assessed the effect of extended storage at −4°C (0 to 24 wk) and 2°C (0 to 8 wk) on SL and reported that WBSF values of SL steaks after 12 wk of storage at −4°C were lower than those stored for 4 wk at −4°C. The authors further reported that WBSF values of steaks after 8 wk of chilled storage (2°C) were lower than those after 4 wk of storage at the same temperature (Lu et al., 2019). However, WBSF values of samples after 4 wk of chilled storage (2°C) were significantly lower than those of samples held for 12 wk at −4°C, indicating that the time and temperature of storage can have an impact on tenderness. Similarly, Karney et al. (2022) performed WBSF analyses on SL that had been wet-aged at 0°C for 14, 21, 28, 35, 49, or 63 d and reported that 49 and 63 d aged samples had the lowest WBSF values, while 21, 28, and 35 d aged steaks had similar values.

Consumers’ eating satisfaction is crucial when new technologies are being evaluated to extend beef shelf life since it is documented that consumers are willing to pay more for beef that meets their eating expectations (Lyford et al., 2010). Generally, beef palatability is attributed to juiciness, tenderness, and flavor (Smith and Carpenter, 1974), and these primary sensory traits were evaluated in the current study, along with overall liking. The term “juiciness” describes the sensation that occurs when meats have higher levels of juices, and it is positively associated with consumer preference (Maughan et al., 2012). The changes in the juiciness of steaks from the different LT storage periods varied depending on the cut evaluated. However, regardless of the cut, consumers could not detect differences in juiciness among any of the storage treatments. These results agreed with cooking loss, where no differences were observed. The lack of differences in juiciness, regardless of the storage time, could be because all samples were from upper two-thirds Choice carcasses, where the amount of marbling is moderate (Emerson et al., 2013). Laster et al. (2008) performed consumer sensory evaluations on RE and SL steaks that were wet-aged at −0.6°C ± 1.8°C for 14, 21, 28, and 35 d (after initial aging for 9 d during shipment) and reported no differences in the juiciness levels of RE and SL steaks over the aging periods.

In the current study, consumers were able to detect differences in tenderness with the storage time for IR and SL samples. However, they could not detect differences in tenderness for RE steaks, regardless of the storage time. This result is also in agreement with Laster et al. (2008), where consumers were unable to detect the differences in tenderness of RE after wet aging. The percentage of acceptance of tenderness did not vary by storage time, irrespective of the cut (Table 1). Moreover, these observations in consumer evaluations were consistent with the WBSF results, where WBSF values of LT90 IR and SL steaks were more than 1 kg lower compared to IR and SL steaks aged for 21 d. Specifically, the WBSF values of LT75 and LT90 IR steaks were lower than those of 21 d wet-aged samples, and WBSF values of LT90 SL steaks were lower than those of LT60 samples. Although there was a statistical difference between WBSF values of LT90 RE steaks and WBSF values of LT60 and 21 d wet-aged RE samples, the change was less than 1 kg, which could explain why consumers could not perceive the difference (Miller et al., 1995).

Several studies have demonstrated that flavor is of great importance when tenderness is acceptable (Goodson et al., 2002; Killinger et al., 2004; Behrends et al., 2005), and a recent study indicated that it could have more influence than tenderness on overall consumer eating satisfaction of beef (O’Quinn et al., 2018). In the current study, as storage time increased, flavor scores numerically increased for IR and SL steaks (Figure 3C and 5C), whereas flavor scores numerically decreased for RE steaks (Figure 4C); however, none of these changes were statistically significant. The overall liking scores of samples were similar for all storage times, regardless of the cut evaluated (Figure 3D, 4D, and 5D). Similar to the present study, Colle et al. (2015) assessed the flavor and overall liking of SL steaks aged (2, 14, 21, 42, and 63 d) at 0°C and reported no differences in either attribute across the different aging periods. In contrast, Garmyn et al. (2020) evaluated flavor and overall liking every 7 d of SL aged at 2°C from 21 to 84 d and reported a significant decrease as postmortem aging time increased. Differences in results from the current study compared to others, where overall liking decreased with aging time, could be due to the lower temperature used during storage. Previously, Juárez et al. (2010) demonstrated that storage temperature could affect the off-flavor intensity, with SL and IR steaks stored at 5°C having a greater off-flavor compared to steaks stored at 1°C. A recent study (Hernandez et al., 2023) evaluated the influence of storage temperature (−2°C, 0°C, or 4°C) and duration (14, 28, 42, or 56 d) of vacuum-packaged beef SL on palatability, and it was reported that off-flavors, such as sour notes, were higher on samples aged for 56 d at 4°C compared with those stored for the same time at the lower temperatures.

Conclusions

Tenderness and palatability attributes are important when new processes are being evaluated as they affect consumers’ eating satisfaction and repurchase decisions. In the current study, the WBSF values of IR, RE, and SL steaks decreased over LT storage time (up to 90 d), and perceived tenderness by consumers increased with no adverse effect on juiciness, flavor, and overall liking. These results suggested that storage temperatures lower than typical chilling temperatures could extend the storage life of beef while preserving or even improving sensory performance. With seasonality in beef price and consumption, these results can be useful to the meat industry to stabilize supply.