- Email: [email protected]
Bovine M. longissimus thoracis meat quality differences due to Canada quality grade
Meat Science 155 (2019) 43–49
Contents lists available at ScienceDirect
Meat Science journal homepage: www.elsevier.com/locate/meatsci
Bovine M. longissimus thoracis meat quality differences due to Canada quality grade J. Puentea, S.S. Samantab, H.L. Brucea, a b
T
⁎
Department of Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Building, University of Alberta, Edmonton, Alberta T6G 2P5, Canada Department of Electrical and Computer Engineering, Electrical and Computer Engineering Research Facility, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
A B S T R A C T
Differences in meat quality characteristics between the four Canada beef quality grades (Canada Prime, AAA, AA, and A) at days 4 and 18 post mortem were investigated using 48 (n = 12/grade) bovine M. longissimus thoracis (LT, rib eye). There was no difference in intramuscular fat content between Canada A and AA LT, and Canada AA LT had a higher mean Warner-Bratzler shear force (WBSF) than LT from all other grades (P = 0.0009) at day 18 post mortem. Canada Prime muscles were lighter and yellower than muscle from all other grades, and their increased lightness persisted with ageing. Mean cooking loss was lowest in Canada Prime LT and correlated with intramuscular fat content (r = −0.41 and − 0.29, days 4 and 18, respectively). Results confirmed differences in cooked product toughness can exist between the grades, with the potential for reduced tenderization in Canada AA LT.
1. Introduction Meat quality is the culmination of the acceptability of a meat product in terms of its colour, tenderness, juiciness, flavor and aroma (Madruga, Elmore, Oruna-Concha, Balagiannis, & Mottram, 2010; Renerre, 1982). In Canada, beef under thirty months of age that meets texture, muscling, fat and lean colour requirements is classified into four quality grades based upon the amount of intramuscular fat in the M. longissimus thoracis (LT; rib eye) muscle surface at the 12th and 13th rib interface. The Canada quality grades are: Canada A (traces of marbling); Canada AA (slight marbling); Canada AAA (small marbling); and Canada Prime (slightly abundant marbling) (Anonymous, 2007), and are synonymous with USDA Standard, Select, Choice and Prime grades respectively. Beef carcass grading allows for an estimation of the eating quality of beef and as a result this classification is used to set the value of the whole carcass as well. Although the Canadian beef grading system is used to set the value of the whole carcass, neither the true meat quality profile of each grade nor the meat quality differences among Canada grades were compared until recently. The most recent comparison of beef quality properties by beef grade was Puente, Samanta, and Bruce (2016), with prior examination conducted by Hawrysh and Berg (1976), while the effects of marbling level on cooking and palatability properties of beef rib-eye steaks was described by Jones, Jeremiah, Tong, Lutz, and Robertson (1991). In a study by Lyford et al. (2010), it was demonstrated that consumers were willing to pay additional money for increased beef eating quality especially in the Japanese market in a study that included Japan, the United States of
⁎
America (USA), Australia and Ireland. Also, in the same study, consumers were willing to pay 1.7 and 2.9 times the price for 4 and 5 star quality respectively, when 3 stars represented the “good everyday” quality, while consumers were willing to pay only half price for the 2 star product. Several studies have reported that meat tenderness is the most important quality trait for the consumer (Savell et al., 1987; Verbeke, Pérez-Cueto, de Barcellos, Krystallis, & Grunert, 2010) and have shown that consumers are willing to pay an increased price for guaranteed tender meat (Boleman et al., 1997; Miller, Carr, Ramsey, Crockett, & Hoover, 2001; Platter et al., 2003). Understanding which meat quality characteristics contribute to and affect tenderness is important, particularly the influence of intramuscular fat (marbling) because marbling score is the only parameter used to differentiate between the Canada quality grades. This study tested the null hypothesis that there is no difference in technological meat quality characteristics of the LT between the grades with the exception of intramuscular fat content and the concomitant changes to moisture and protein content. Therefore, the objectives of this study were to: 1) characterize the instrumental meat quality differences between the LT from the four quality Canada grades; and 2) understand the relationship between fat content and tenderness. 2. Materials and methods 2.1. Experimental design Twelve LT (rib eye) muscles from each quality grade (Canada A, AA,
Corresponding author. E-mail address: [email protected] (H.L. Bruce).
https://doi.org/10.1016/j.meatsci.2019.05.002 Received 31 October 2018; Received in revised form 29 January 2019; Accepted 1 May 2019 Available online 02 May 2019 0309-1740/ © 2019 Elsevier Ltd. All rights reserved.
Meat Science 155 (2019) 43–49
J. Puente, et al.
AAA & Prime) were obtained from a large Alberta abattoir at 3 days post mortem over four shipments. Personnel certified as meat graders by the Canadian Beef Grading Agency determined the quality grade of each carcass from which the muscles were derived within 24 h post mortem by viewing the surface of the M. longissimus thoracis muscle at the 12th and 13th rib interface. A total of 48 LT muscles were accepted into the study. From the posterior of each muscle portion (12th–13th rib interface), four 2.5 cm thick steaks were removed, with the first steak used for objective colour measurements, the second used for proximate analyses, the third for cooking loss and Warner–Bratzler shear force (WBSF), and the fourth for pH and drip loss. The remainder of the LT section was then stored at approximately 4 °C for an additional 14 days under vacuum. From the aged portion, steaks were removed from the posterior of the LT section, with the first steak removed used for objective colour measurements, the second steak used for cooking loss and Warner–Bratzler shear force, and the third steak used for pH and drip loss.
Table 1 Meat quality characteristics of beef M. longissimus thoracis from each of the Canada quality grades at 4 days post mortem. Analysis
n L* a* b* pH Drip loss (%) Cook loss (%) Cook Time (min/100 g) WBSF3 (Newton)
Canada grade A
AA
AAA
Prime
12 36.3a 18.5 2.9a 5.3a 0.8 17.2a 2.2a 42.6
12 36.8a 19.2 3.6a 5.3a 0.7 18.7a 2.4ab 44.9
12 35.9a 20.3 3.6a 5.4ab 0.6 15.9ab 2.4ab 45.0
12 39.4b 21.3 5.9b 5.5b 0.5 14.6b 2.6b 32.2
Pr > F1
SEM2
0.0006 0.0734 0.0022 0.0494 0.0567 0.0017 0.054 0.1240
0.88 1.15 0.80 0.04 0.29⁎ 0.70 0.12 4.28
a,b
Means with different superscripts within a row are significantly different at P < .05 according to least square mean differences tests. 1 Probability of the calculated F value with significance at P ≤ .05. 2 SEM - Standard error of the mean. 3 WBSF – Warner-Bratzler Shear Force.
2.2. Colour analysis Colour analysis is improved by increasing the number of measurements within a sample (Alcalde & Negueruela, 2001); therefore, 3 locations on the LT muscle surface were chosen at random for measurement. Colour values across the three measurements were averaged and the mean of each value recorded for statistical analysis. Prior to colour analysis, approximately 3 mm of the outside face was removed and the newly exposed surface was allowed to bloom (oxygenation) in a tray covered with oxygen-permeable polyvinyl-chloride film (Fisher Scientific, Pittsburgh, PA, USA.) at 4 °C for 60 min. Lightness (L*), green-red (a*) and blue–yellow (b*) were determined with a Minolta Chromameter CR-400 (Konica-Minolta, Osaka, Japan) using the colour system established by the Commission Internationale de L'Eclairage (CIE)(CIE, 1976). The instrument was calibrated before use against a white tile provided with the instrument.
cooled to < 10 °C in an ice bath and then weighed the next day after storage at about 4 °C. Cooking loss was calculated by dividing the steak weight loss during cooking by the raw weight of the steak and reported as a percentage of the initial raw weight. Cooking time was recorded every 3 min until steak internal temperature reached 71 °C using a fourchannel alarm timer (Traceable ®, Fisher Scientific, Edmonton, AB, Canada), and cooking time was calculated as minutes/100 g of fresh product. 2.5. Warner-bratzler shear force Cooked steaks were stored overnight at 4 °C, and the following day steaks were removed from refrigerated storage and allowed to reach room temperature. Once the cooked steaks reached room temperature, 6 cores of 1.27 cm diameter and 2 cm long were removed from each steak parallel to the muscle fibers using a cork borer. Each core was sheared once across the middle, perpendicular to the fiber direction, using a materials testing machine (AMETEK, Inc. Lloyd Instrument LRX plus, Digital Metrology Measurements, Kitchener, ON, Canada) fitted with a Warner–Bratzler type shear blade travelling at 225 mm/min. Shear force was expressed in Newtons (N) and values were averaged to obtain a mean value for each steak.
2.3. Intramuscular pH Measurements of pH were performed with a temperature-compensated pH meter (Fisher Scientific, Accumet Waterproof AP71 pH/mV/ Temperature, Fisher Scientific, Toronto, ON, Canada) fitted with a glass probe electrode (Hanna Instruments, Fisher Scientific, Toronto, ON, Canada) which was inserted into the muscle. Three readings were taken from each muscle and the pH values were averaged and the mean used for statistical analysis. Prior to pH measurement, the pH meter and electrode were standardized using commercial pH buffers of 4.0 and 7.0 at room temperature (23 °C).
2.6. Proximate analyses To determine the chemical composition of the beef samples, approximately 100 g of steak was cubed, weighed, placed into an aluminium tray, and lyophilized using a freeze dryer (Virtis freeze dryer ultra El-85, SP Scientific, Warminster, PA., USA). Upon the completion of lyophilisation, the trays were removed from the freeze dryer and final weights recorded for moisture loss calculation. Crude fat analysis was determined by pulverizing the freeze-dried sample into a fine powder using a blender fitted with a 1 L stainless steel container (Two-Speed Food Blender Model 7011G; Waring Commercial. Torrington, CT, USA) containing two to three pellets of dry ice. Duplicates of about 2 g each of this dry meat powder were placed in thimbles and analyzed for crude fat content (Method 960.39; Association of Official Analytical Chemists, 1995) by petroleum ether extraction (Goldfisch Fat Extraction Apparatus Model 35,001; Labconco Corp. Houston, TX, USA). A blank/ control sample was run at all times, and duplicates were averaged for statistical analysis. Nitrogen content was determined using triplicates of 100 mg of ground dry meat sample (Method 992.15; Association of Official Analytical Chemists, 1997) (Nitrogen/Protein Determinator CNS2000, Leco Corp., St., Joseph, MI., USA) and triplicates were averaged and means used for statistical analysis. Standardization and
2.4. Drip loss, cooking loss and cook time Drip loss was determined as described by Honikel (1998) and as outlined by the American Meat Science Association methods (AMSA, 1995). Drip loss was measured by first trimming the external fat from the LT steak where weights ranged from 106 to 200 g (Table 1). Trimmed steak samples were hung for 24 h at 4 °C in a closed plastic bag from a stainless steel hook. The weight of each trimmed steak portion was recorded before and after the procedure, and weight loss results expressed as a percentage of the original weight. To calculate cooking loss, additional LT steaks were trimmed of subcutaneous fat, weighed and grilled on a pre-heated grill (General Electric 4 in 1 Grill/Griddle, China) at 176 °C. The internal temperature of each steak was monitored continuously using a thermometer with a metal probe (Tinytag View 2 s, Interworld Electronics and Computer Industries Inc., West Vancouver, BC, Canada) inserted into the geometric centre of the steak. Steaks were heated until the steak internal temperature reached 71 °C. Once an internal temperature of 71 °C was reached, the cooked steaks were placed in a polypropylene bag and 44
Meat Science 155 (2019) 43–49
J. Puente, et al.
were the most yellow (b*) at day 4 post mortem (Table 1). There were no differences in a* values (coordinate green–red) among the grades regardless of additional ageing, although the mean value for the Canada Prime LT at day 4 post mortem approached significance for being the most red (P = 0.07). Mean b* values for the Canada Prime LT were greater than that of all other grades, which were not different from each other (Table 1), and in the steaks from the LT aged for an additional 14 days the difference in b* value between the Canada A and Prime LT approached significance (P = 0.06), with Canada A LT being the most blue and the Canada Prime LT being the most yellow. Mean intramuscular ultimate pH value for the 4 day post mortem samples was statistically greatest for the Canada Prime LT, which was not different from LT from Canada AAA carcasses (Table 1). In the portions that received an additional 14 days of ageing, however, there was no difference in the mean ultimate pH of the LT muscles across the grades (Table 2).
calibration prior to nitrogen analysis were performed with caffeine and ethylenediaminetetraacetic acid (EDTA) in triplicate prior to meat sample analyses. 2.7. Statistical analyses Data from non-aged (4 days) and aged (18 days) beef were analyzed in separate data sets due to ageing treatment being confounded with sample location along the LT. Data were organized as a randomized complete block design within day of ageing and analyzed using the MIXED procedure in the Statistical Analysis System (SAS) software (Version 9.2, Statistical Analysis Systems, Cary, NC, USA). Analysis of variance was conducted using beef grade as the sole fixed effect. Ribs were blocked by replicate and block was included as a random source of variation. Grade effect was considered significant at P ≤ 0.05 and, where grade was significant, least square mean differences were used to determine differences between grade means with significance at P ≤ 0.05. In all analyses of variance, degrees of freedom were corrected using the Kenward-Roger adjustment. Correlations were performed using PROC CORR to obtain Pearson correlations between the meat quality data to calculate linear dependence among variables. Correlation analyses were performed on drip and cooking loss percentages and steak weight to identify any dependence of drip and cooking loss percentages on steak weight. The randomized complete block design model was:
3.2. Drip loss, cooking loss and cook time Differences in drip loss between the grades approached significance (P = 0.057) with the Canada A day 4 post mortem LT steaks tending to have the most drip loss (Table 1). This tendency was not noted in the LT aged an additional 14 days, however, with these LT muscles showing no effect of grade on drip loss (Table 2). There were significant differences (P = .0017) within the day 4 post mortem LT due to grade for cooking loss, with Canada Prime LT having a lower mean cooking loss value than that of LT from all other grades (Table 1) with the exception of LT from Canada AAA carcasses, and this difference persisted in the aged samples (P = 0.02) (Table 2). Differences in cooking time for LT between the grades approached significance (P = 0.054) with the non-aged LT from the Canada Prime grade tending to require a longer time to reach 71 °C (Table 1). This tendency was not noted in the LT portion aged an additional 14 days, where the additionally-aged LT muscles showed no effect of grade on cooking time (Table 2).
yij = μ + Gi + Bj + εij. where μ was the overall mean, Gi was the grade codified with i = 1.0.4, Bj was the block where j = 1..0.12, and εij was the random deviation associated with each observation. Multiple regression analysis was performed relating meat quality measurements to peak WBSF using simple linear regression (PROC REG, SAS Version 9.2) with the stepwise selection function. Entry into the model was at P ≤ 0.05. Correlations between eligible measurements were determined using Pearson correlations (PROC CORR, SAS Version 9.2) prior to multiple regression analysis, and only measurements that were not correlated with each other were included in the regression.
3.3. Warner-bratzler shear force There were no differences in mean Warner-Bratzler shear force (WBSF) values between the grades in the day 4 post mortem LT (P = 0.12) (Table 1). Differences were found (P = 0.0009) in the LT portions aged an additional 14 days, with Canada AA LT having the highest and Canada AAA and Prime LT having the lowest WBSF values (Table 2).
3. Results 3.1. Colour and ultimate pH With and without additional ageing, LT steaks from Canada Prime carcasses had the highest mean L* values (Table 1 and Table 2) and
3.4. Proximate analyses Table 2 Meat quality characteristics of beef M. longissimus thoracis from each of the Canada quality grades at 18 days post mortem. Analysis
n L* a* b* pH Drip loss (%) Cook loss (%) Cook time (min/100 g) WBSF3 (Newton)
Canada grade
Pr > F1
SEM2
A
AA
AAA
Prime
12 33.2b 19.1 1.2 5.5 0.81 15.5a 2.1
12 32.6b 20.9 2.6 5.5 0.72 16.1a 2.0
12 31.8b 21.0 1.8 5.5 0.72 14.0ab 2.1
12 35.7a 21.1 3.1 5.6 0.69 12.7b 2.1
< 0.0001 0.4664 0.0611 0.3731 0.1906 0.0204 0.66
1.1 1.5 0.73 0.03 0.14⁎ 1.1 0.12
44.1a
52.6b
35.7c
39.6ac
0.0009
5.0
Proximate analyses were performed on day 4 post mortem LT muscle only. Differences in crude fat content between the grades were significant as anticipated (P < 0.0001), with the Canada Prime LT having the highest mean crude fat content (11.57%), followed by Canada AAA LT (4.62%). The lowest crude fat contents were observed in LT from the Canada AA (3.11%) and A grades (2.92%), the means of which were not significant different from each other (Table 3). Differences in moisture content were significant (P < 0.0001), with Canada Prime having the lowest moisture content (64.64%), lower than the mean moisture contents of LT muscles from the Canada AAA, AA and A grades, which were not different from each other (Table 3). Protein content varied by grade as well (P < 0.0001), with LT from the Canada A and AA having the highest mean protein contents and the LT from the Canada AAA and Canada Prime having the lowest protein contents (Table 3).
a,b
Means with different superscripts within a row are significantly different at P < .05 according to least square mean differences tests. 1 Probability of the calculated F value with significance at P ≤ .05. 2 SEM - Standard error of the mean. 3 WBSF – Warner-Bratzler Shear Force.
3.5. Pearson correlations For measurements performed at day 4 post mortem, there was no 45
Meat Science 155 (2019) 43–49
J. Puente, et al.
(P < 0.05). Cooking time was correlated to crude fat (r = 0.32) and moisture (r = −0.37)(P < 0.05), crude fat was correlated to moisture (r = −0.84) and protein contents (r = −0.65)(P < 0.0001), and moisture was correlated to protein (r = 0.35)(P < 0.05). For LT aged an additional 14 days, significant correlations were found (Table 7). L* was correlated to b* (r = 0.61, P < 0.0001) and crude fat (r = 0.32, P < .05) while a* was correlated to b* (r = 0.66, P < .0001), pH (r = −0.36) and Warner-Bratzler shear force (r = −0.45)(P < 0.05). Also, b* was correlated to pH (r = −0.28), drip loss (r = −0.29), cooking loss (r = 0.28), and protein content (r = −0.29)(P < .05). Intramuscular pH was correlated to crude fat (r = 0.35), drip loss was correlated to protein content (r = 0.29), and cooking loss was correlated to cooking time (r = 0.48), crude fat (−0.29) and moisture content (r = 0.41)(P < 0.05). Warner-Bratzler shear force and cooking time were correlated to protein (r = 0.32) and cooking time to protein content (r = −0.37)(P < 0.05). Crude fat was correlated to moisture (r = −0.84) and protein (r = −0.65) (P < 0.0001), while moisture was correlated to protein (r = 0.35) (P < 0.05).
Table 3 Means of proximate analyses from beef M. longissimus thoracis from each of the Canada quality grades. Analysis (%)
n Crude fat Moisture Protein
SEM2
Canada grade A
AA
AAA
Prime
Pr > F1
12 2.92 a 70.63 a 24.33 a
12 3.11 a 70.69 a 24.34 a
12 4.62 b 69.28 a 23.56 b
12 11.57 c 64.64 b 22.14c
< 0.0001 < 0.0001 < 0.0001
0.4879 0.8850 0.3493
a,b,c Means with different superscripts within a row are significantly different at P < 0.05 according to least square mean differences tests. 1 Probability of the calculated F value with significance at P ≤ 0.05. 2 SEM - Standard error of the mean.
Table 4 Pearson correlation coefficients between drip loss factors (at 4 and 18 days ageing combined) for beef M. longissimus thoracis from all Canada quality grades. Variable
Steak weight before (g)
Steak weight after (g)
Drip loss (g)
Drip loss (%)
Steak weight before (g) Steak weight after (g) Weight loss (g)
1.00
0.99 < 0.0001 1.00
0.47 < 0.0001 0.46 < 0.0001 1.00
−0.00 0.9340 −0.02 0.8360 0.86 < 0.0001 1.00
Drip loss (%)
0.99 < 0.0001 0.47 < 0.0001 −0.00 0.9340
0.46 < 0.0001 −0.02 0.8360
0.86 < 0.0001
3.6. Multiple regression Stepwise multiple regression analysis indicated that the a* value was the best and only predictor of WBSF value at both day 4 post mortem (P = 0.0002, partial R2 = 0.25)(Eq. (1)) and after an additional 14 days ageing (P = 0.0011, partial R2 = 0.21)(Eq. (2)). Partial R2 values indicated that the a* value described approximately 25 and 20% of the variation in WBSF at days 4 and 18 post mortem, respectively.
Table 5 Pearson correlation coefficients between cooking loss measurements for beef M. longissimus thoracis from each of the Canada quality grades (days 4 and 18 post mortem combined). Variable
Steak raw weight Steak trimmed weight Steak cooked Weight Steak weight loss
Steak raw weight
Steak trimmed weight
Steak cooked weight
Steak weight loss
Cook loss (%)
1.00
0.90 < 0.0001 1.00
0.85 < 0.0001 0.97 < 0.0001 1.00
0.68 < 0.0001 0.68 < 0.0001 0.50 < 0.0001 1.00
0.17 0.09 0.08 0.4007 −0.13 0.1781 0.77 < 0.0001
WBSF = 96.93891–2.56501(a∗value)
(1)
WBSF = 73.03827–1.39596(a∗value)
(2)
4. Discussion The Canadian beef quality grades are discerned by the degree of intramuscular fat or “marbling”, which is assessed subjectively during beef carcass grading by trained personnel and characterized as a visual marbling score. The effectiveness of this assessment was supported by the results of this study as there were differences in crude fat content of the beef from the various Canada quality grades, with the exception of the LT from Canada A and AA carcasses, which were not different. Puente et al. (2016) also found that the mean intramuscular fat contents of the LT from Canada A and AA carcasses were not different, and indicated that the sporadic occurrence of fat throughout the muscle may lead to over or underestimation of marbling in the muscle. This phenomenon has been reported by other researchers (Campion & Crouse, 1975), and suggests that an alternative to visual estimation of marbling may be warranted when low levels of intramuscular fat are present. Near-infrared spectroscopy is used to estimate fat content in ground and whole meats (Prieto, Roehe, Lavin, Batten, & Andrés, 2009), as it provides some level of penetration into the muscle, and so its application as a grading aid may warrant investigation. Intramuscular fat is subjectively assessed in the Canadian and USA beef grading systems most likely because it has been associated with favourable palatability, which has been attributed to improved product flavor (Corbin et al., 2015). Previous studies have shown that the degree of marbling has no effect on cooked product toughness (Jones et al., 1991; Puente et al., 2016), although Puente et al. (2016) found that intramuscular crude fat content was negatively correlated to WBSF before but not after 14 days of ageing. In the present study, there was no difference in mean shear force values due to Canada grade at 4 days post mortem, but LT from Canada AAA and Prime carcasses had lower mean WBSF values than LT from the other grades after 14 days additional ageing. Crude fat content was negatively correlated (r = −0.36)
significant correlation between the weight of trimmed steaks used for drip loss and the actual percentage of drip loss (P = 0.93) (Table 4). The linear correlation between steak weight and cooking loss, however, approached significance (P = 0.093) (Table 5). For day 4 post mortem LT, L* was correlated to b* (r = 0.39), cook time (r = 0.30), crude fat (r = 0.51), moisture (r = −0.45) and protein content (r = −0.31) (P < 0.05)(Table 6). For other colour coordinates, a* was correlated to b* (r = 0.41), Warner-Bratzler shear force (r = −0.50), and moisture (r = −0.45) and protein contents (r = −0.31)(P < 0.05). In addition, b* was correlated to drip loss (r = −0.34), cooking loss (r = −0.29), and fat (r = 0.40) and protein (r = −0.50)(P < 0.05) contents. Intramuscular pH was correlated to drip loss (r = −0.40), cooking loss (r = −0.35), crude fat (r = 0.49) and protein contents (r = −0.42), and drip loss was correlated to protein content (r = 0.32)(P < 0.05). Cooking loss was correlated to Warner-Bratzler shear force (r = 0.38), crude fat (−0.41), moisture (r = 0.29) and protein content (r = 0.43)(P < 0.05). Warner-Bratzler shear force was correlated to cook time (r = 0.33), crude fat (r = −0.36), moisture (r = 0.36) and protein contents (r = 0.29) 46
Meat Science 155 (2019) 43–49
J. Puente, et al.
Table 6 Pearson correlation coefficients between meat quality measurements performed on beef M. longissimus thoracis from all Canada quality grades at 4 days post mortem. Variable
L⁎
a⁎
b⁎
pH
Drip Loss (%)
Cook Loss (%)
WBSF1 (Newton)
Cook time (min/100 g)
Fat content (%)
Moisture content (%)
Protein content (%)
n L⁎ a⁎ b⁎ pH Drip loss (%) Cook Loss (%) WBSF (Newton) Cook time (min/ 100 g) Fat content (%) Moisture content (%) Protein content (%)
48 1.00 −0.05 0.39⁎ 0.27 −0.12 −0.18 −0.09 0.30⁎
48 −0.05 1.00 0.41⁎ 0.08 0.07 −0.08 −0.50⁎ 0.04
48 0.39⁎ 0.41⁎ 1.00 0.10 −0.34⁎ −0.29⁎ −0.03 0.23
48 0.27 0.08 0.10 1.00 −0.40⁎ −0.35⁎ −0.14 0.04
48 −0.12 0.07 −0.34⁎ −0.40⁎ 1.00 0.27 −0.19 −0.06
48 −0.18 −0.08 −0.29⁎ −0.35⁎ 0.27 1.00 0.38⁎ 0.11
48 −0.09 −0.50⁎ −0.03 −0.14 −0.19 0.38⁎ 1.00 0.33⁎
48 0.30⁎ 0.04 0.23 0.04 −0.06 0.11 0.33⁎ 1.00
48 0.51⁎ 0.27 0.40⁎ 0.49⁎ −0.27 −0.41⁎ −0.36⁎ 0.32⁎
48 −0.45⁎ −0.23 −0.21 −0.26 0.12 0.29⁎ 0.36⁎ −0.37⁎
48 −0.31⁎ −0.31⁎ −0.50⁎ −0.42⁎ 0.32⁎ 0.43⁎ 0.29⁎ −0.15
0.51⁎ −0.45⁎
0.27 −0.23
0.40⁎ −0.21
0.49⁎ −0.26
−0.27 0.12
−0.41⁎ 0.29⁎
−0.36⁎ 0.36⁎
0.32⁎ −0.37⁎
1.00 −0.84⁎⁎
−0.84⁎⁎ 1.00
−0.65⁎⁎ 0.35⁎
−0.31⁎
−0.27
−0.50⁎
−0.42⁎
0.32⁎
0.43⁎
0.29⁎
−0.15
−0.65⁎⁎
0.35⁎
1.00
WBSF – Warner-Bratzler Shear Force. P ≤0.05. ⁎⁎ P ≤0.0001. 1 ⁎
Table 7 Pearson correlation coefficients between meat quality measurements performed on beef M. longissimus thoracis at 18 days post mortem. Variable
L⁎
a⁎
b⁎
pH
Drip Loss (%)
Cook Loss (%)
WBSF1 (Newton)
Cook time (min/100 g)
Fat content (%)
Moisture content (%)
Protein content (%)
n L⁎ a⁎ b⁎ pH Drip loss (%) Cook loss (%) WBSF (Newton) Cook time (min/ 100 g) Fat content (%) Moisture content (%) Protein content (%)
48 1.00 0.26 0.66⁎⁎ −0.14 −0.05 0.15 −0.09 0.06
48 0.26 1.00 0.66⁎⁎ −0.36⁎ 0.06 0.18 −0.45⁎ 0.06
48 0.61⁎⁎ 0.66⁎⁎ 1.00 −0.28⁎ −0.29⁎ 0.28⁎ −0.15 0.26
48 −0.14 −0.36⁎ −0.28⁎ 1.00 −0.13 −0.12 0.11 −0.02
48 −0.05 0.06 −0.29⁎ −0.13 1.00 0.03 −0.06 −0.15
48 0.15 0.18 0.28⁎ −0.12 0.03 1.00 0.22 0.48⁎
48 −0.09 −0.45⁎ −0.15 0.11 −0.06 0.22 1.00 0.09
48 0.06 0.06 0.26 −0.02 −0.15 0.48⁎ 0.09 1.00
48 0.32⁎ 0.07 0.10 0.35⁎ −0.20 −0.29⁎ −0.19 0.06
48 −0.17 −0.05 0.07 −0.16 0.02 0.41⁎ 0.18 0.09
48 −0.27 −0.12 −0.29⁎ −0.15 0.29⁎ 0.04 0.32⁎ −0.37⁎
0.32⁎ −0.17
0.07 −0.05
0.10 0.07
0.35⁎ −0.16
−0.20 0.02
−0.29⁎ 0.41⁎
−0.19 0.18
0.06 0.09
1.00 −0.84⁎⁎
−0.84⁎⁎ 1.00
−0.65⁎⁎ 0.35⁎
−0.27
−0.12
−0.29⁎
−0.15
0.29⁎
0.04
0.32⁎
−0.37⁎
−0.65⁎⁎
0.35⁎
1.00
WBSF – Warner-Bratzler Shear Force. P ≤0.05. ⁎⁎ P ≤0.0001. 1 ⁎
were highest for the portion of the muscle farthest away from the 12th–13th rib interface. Shear force values before and after ageing may also be affected by the cooking method (Obuz, Dikeman, Grobbel, Stephens, & Loughin, 2004) as there is the potential for grilling equipment to cook differently between the ageing periods. After the additional 14 days ageing, WBSF analysis results indicated that the LT from Canada AAA carcasses had a lower mean WBSF value than LT from Canada A and AA carcasses, but similar to that from Canada Prime carcasses. This result suggested that Canada AAA LT had a greater capacity to tenderize than LT from the A and AA grades. Gruber et al. (2006) found that LT steaks containing high levels of intramuscular fat exhibited a greater decline in WBSF value with post mortem ageing, although Puente et al. (2016) did not. Puente et al. (2016) did find that the difference in mean WBSF values between LT steaks from Canada AAA and Prime carcasses and from Canada A and AA carcasses approached significance (P = .099), with Canada AA LT tending to have the highest mean WBSF value, and the WBSF results for the LT aged an additional 14 days in the present study agreed with this trend. Considering the effect of intramuscular fat content on not only toughness but colour is warranted because colour is one of the most important factors to influence customers during purchasing of meat (Hood & Riordan, 1973). The current study showed that, without an additional 14 days of ageing, LT from the Canada Prime grade had a
with Warner-Bratzler shear force at 4 days post mortem, but this correlation disappeared after 14 days additional ageing, suggesting that other factors were instrumental in the determination of cooked product toughness. Although not compared statistically, the mean shear force values for the LT aged an additional 14 days were unexpectedly higher than those measured at 4 days post mortem, in contrast to the literature that shows that meat tenderizes with time after animal exsanguination (Koohmaraie, Seidemann, Schollmeyer, Dutson, & Crouse, 1987). Means for WBSF before and after an additional 14 days ageing were not compared statistically because ageing treatment was confounded with position within the LT, with the steak from the portion aged an additional 14 days being farthest from the 12th–13th rib interface (approximately 5 in.) than the LT steak assessed for WBSF at 4 days post mortem. Randomization of samples from different muscle regions is warranted when comparing ageing treatments within the same muscle despite the existence of studies in which this is not considered (Mehaffey et al., 2009), as position would not then need to be considered as a source of variation between the ageing treatments. Steak location within the M. longissimus thoracis et lumborum may affect WBSF value, as Janz, Aalhus, Dugan, and Price (2006) found that LT steaks located close to the 12th–13th rib interface were tougher than those close to the shoulder (Janz et al., 2006). The results of the present study do not concur with those of Janz et al. (2006), as the mean WBSF values 47
Meat Science 155 (2019) 43–49
J. Puente, et al.
present study, the a* value accounted for about 25% of the variability in WBSF, with the proportion it was able to describe declining with time post mortem, suggesting that factors other than muscle pH or early post mortem temperature were most determinant of WBSF as time post mortem.
greater luminosity (L*) and yellowness (b*) than LT from the other Canada quality grades. Luminosity remained increased in the Canada Prime LT after an additional 14 days ageing, and the increased b* value of the Canada Prime LT relative to that of the LT from the other grades after the additional 14 days ageing approached significance as well. Puente et al. (2016) also noted an increase in yellowness with marbling that persisted with ageing, although no difference in luminosity was observed between the LT from the four quality grades. Lean L* and b* values at 4 and 18 days may have been increased in the Canada Prime LT by the large amount of intramuscular fat related to this grade, as increased lightness of lean has been related to warm muscle temperatures early post mortem (Bruce & Ball, 1990). Warm muscle temperatures early post mortem could arise from increased subcutaneous fat, which has been associated with carcasses that have high levels of marbling (Moon, Yang, Park, & Joo, 2006). An increased early post mortem temperature can denature muscle proteins, which can increase luminosity and yellowness either through structural alteration of the myofibrillar proteins (Sleper, Hunt, Kropf, Kastner, & Dikeman, 1983) or increased water exudation (Scopes, 1964; Scopes, 1970). That there were increased muscle temperatures in the Canada AAA and Prime carcasses was not verified in the present experiment, but is supported by significant positive correlations between intramuscular fat content and L* and b* values at day 4 post mortem (r = 0.51 and 0.40, respectively), and L* after the 14 days additional ageing (r = 0.32). The b* value after the 14 days additional ageing appeared to be more related to intramuscular pH than marbling, however, as it was negatively correlated to intramuscular pH (r = −0.28), indicating that as muscle pH decreased, yellowness increased after the additional 14 days of ageing. Previous studies have shown that meat colour darkens as intramuscular pH increases (Abril et al., 2001; Puente et al., 2016). In the present study, Canada Prime LT had the highest mean pH and the highest mean L* value, but there was no correlation between muscle pH and L*. As muscle pH increased, a* and b* values would decrease (r = −0.36 and − 0.28, respectively), suggesting darkening related to pH was due to a decrease in redness (increase in blueness) and a decrease in yellowness. This suggested that early post mortem cooling rate may have been more instrumental in muscle lean colour formation than intramuscular pH at the time of measurement (Bruce & Ball, 1990). The lean of Canada A and AA LT muscles may be darker than that of Canada Prime beef due to an increase in the oxygen consumption rate by post rigor beef muscle. The rate of oxygen consumption by beef is decreased by high early post mortem muscle temperature because inner mitochondrial membrane proteins and myoglobin are denatured (Young & West, 2001), and this contributes to an attractive bright red appearance of the exposed meat surface (Bendall & Taylor, 1972). These results suggest that the increased mean L* value of the Canada Prime LT was simply due to the level of intramuscular fat rather than the intramuscular pH. Wulf and Wise (1999) showed that marbling score was weakly but positively correlated to L* value (r = 0.26), as did Pflanzer and de Felicio (2011)(r = 0.34). As noted by Wulf and Wise (1999), the whiteness of intramuscular fat serves to lighten the colour of the muscle, as L* is described on a 0 (black) to 100 (white) axis scale. Colour has been found to be indicative of cooked beef toughness with some success (Peng & Wang, 2015; Sun et al., 2012; Wu et al., 2012) and has been found to be related to early post mortem temperature experienced by the muscle and the use of electrical stimulation (Bruce & Ball, 1990; Li, Li, Li, Hviid, & Lundström, 2011). In the present study, multiple regression analysis indicated that only a* value (redness) was related to WBSF. Wulf, O'Connor, Tatum, and Smith (1997) measured colour at 27 h post mortem and correlations between shear force and L*, a* and b* values were − 0.36, −0.24 and − 0.38, respectively, in that study. Jeremiah, Tong, and Gibson (1991) found that colour explained no > 48% of the variability in cooked beef toughness, and that muscle pH was more effective at predicting cooked beef toughness across the sexes (bulls, heifers and steers) than colour. In the
5. Conclusion This study indicated that LT muscles from Canada Prime and AAA had meat quality characteristics different from those of the other grades, suggesting that Prime and Canada AAA LT are appropriately valued as superior products. Canada A and AA had the lowest fat content of the four grades; therefore, the beef industry could potentially market these grades within consumer populations that express interest in low fat content meat products, although the potential for Canada AA LT to be tougher than the other grades even after ageing warrants consideration. Further research focussing on sensory characterization of beef from the various quality grades is needed so that a complete quality profile of Canadian beef can be achieved. Acknowledgements The authors gratefully acknowledge funding support from Alberta Livestock and Meat Agency, Alberta Innovates-BioSolutions (2009F143R), and the Natural Sciences and Engineering Research Council of Canada. The authors wish to thank staff of the University of Alberta Meat Protein Biochemistry Laboratory and the University of Alberta Agri-Food Discovery Place for excellent technical assistance. References Abril, M., Campo, M. M., Onenç, A., Sañudo, C., Alberti, P., & Negueruela, A. L. (2001). Beef color evolution as a function of ultimate pH. Meat Science, 58, 69–78. Alcalde, M. J., & Negueruela, A. L. (2001). The influence of final conditions on meat color in light lamb carcasses. Meat Science, 57, 117–123. American Meat Science Association (1995). Research guidelines for cookery sensory evaluation and instrumental tenderness measurements of meat. Chicago, IL: American Meat Science Association and National Livestock Meat Board. Anonymous (2007). Livestock and poultry carcass grading regulations (SOR/92–541). Retrieved January/15, 2013, from http://laws-lois.justice.gc.ca/eng/regulations/ SOR-92-541/. AOAC (1995). AOAC official method 960.39. Fat (crude) or ether extract in meat. Final action, AOAC official methods of analysis 1995. Arlington, VA: Association of Official Analytical Chemists. AOAC (1997). AOAC official method 992.15. Crude protein in meat and meat products including pet foods. Combustion method. First action 1992., AOAC official methods of analysis 1995. Supplement march 1997. Arlington, VA: Association of Official Analytical Chemists. Bendall, J. R., & Taylor, A. A. (1972). Consumption of oxygen by the muscle of beef animals and related species, II. Consumption of oxygen by post-rigor muscle. Journal of the Science of Food and Agriculture, 23, 707–719. Boleman, S. J., Boleman, S. L., Miller, R. K., Taylor, J. F., Cross, H. R., Wheeler, T. L., ... Johnson, D. D. (1997). Consumer evaluation of beef of known categories of tenderness. Journal of Animal Science, 75, 1521–1524. Bruce, H. L., & Ball, R. O. (1990). Postmortem interactions of muscle temperature pH and extension on beef quality. Journal of Animal Science, 68, 4167–4175. Campion, D. R., & Crouse, J. D. (1975). Predictive value of USDA beef quality grade factors for cooked meat palatability. Journal of Food Science, 40, 1225–1228. Commission International de l'Éclairage (1976). Official recommendations on uniform colour spaces. Colour Difference Equations and Metric Colour Terms. (Paris., Suppl. No. 2. CIE Publication No. 15 Colorimetry). Corbin, C. H., O'Quinn, T. G., Garmyn, A. J., Legako, J. F., Hunt, M. R., Dinh, T. T. N., ... Miller, M. F. (2015). Sensory evaluation of tender beef strip loin steaks of varying marbling levels and quality treatments. Meat Science, 100, 24–31. Gruber, S. L., Tatum, J. D., Scanga, J. A., Chapman, P. L., Smith, G. C., & Belk, K. E. (2006). Effects of postmortem aging and USDA quality grade on Warner-Bratzler shear force values of seventeen individual beef muscles. Journal of Animal Science, 84, 3387–3396. Hawrysh, Z. J., & Berg, R. T. (1976). Studies on beef eating quality in relation to the current Canada grade classifications. Canadian Journal of Animal Science, 56, 383–391. Honikel, K. O. (1998). Reference methods for the assessment of physical characteristics of meat. Meat Science, 49, 447–457. Hood, D. E., & Riordan, E. B. (1973). Discolouration in pre-packaged beef: Measurement by reflectance spectrophotometry and shopper discrimination. International Journal of Food Science & Technology, 8, 333–343.
48
Meat Science 155 (2019) 43–49
J. Puente, et al.
Platter, W. J., Tatum, J. D., Belk, K. E., Chapman, P. I., Scanga, J. A., & Smith, G. C. (2003). Relationships of consumer sensory ratings, marbling score and shear force value to consumer acceptance of beef strip loin steaks. Journal of Animal Science, 81, 2741–2750. Prieto, N., Roehe, R., Lavin, P., Batten, G., & Andrés, S. (2009). Application of nearinfrared reflectance spectroscopy to predict meat and meat products quality: A review. Meat Science, 83, 175–186. Puente, J., Samanta, S., & Bruce, H. L. (2016). Instrumental meat quality characteristics associated with aged m. longissimus thoracis from the four Canadian beef quality grades. Canadian Journal of Animal Science, 96, 143–153. Renerre, M. (1982). La couleur de la viande et sa mesure. Bulletin technique centre de recherches zootechniques Et Vétérinaires De Theix- INRA. Vol. 47. Bulletin technique centre de recherches zootechniques Et Vétérinaires De Theix- INRA (pp. 47–54). Savell, J. W., Branson, R. E., Cross, H. R., Stiffler, D. M., Wise, J. W., Griffen, D. B., & Smith, G. C. (1987). National Consumer Retail Beef Study: Palatability evaluations of beef loin steaks that differed in marbling. Journal of Food Science, 52, 517–519 (532). Scopes, R. K. (1964). The influence of post-mortem conditions on the solubilities of muscle proteins. Biochemistry Journal, 91, 201. Scopes, R. K. (1970). Characterization and study of sarcoplasmic proteins. In E. J. Briskey, R. G. Cassens, & B. B. Marsh (Eds.). Biochemistry and physiology of muscle as food. Madison: Univ. of Wisconsin Press. Sleper, P. S., Hunt, M. C., Kropf, D. H., Kastner, C. L., & Dikeman, M. E. (1983). Electrical stimulation effects on myoglobin properties of bovine longissimus muscle. Journal of Food Science, 48, 479. Sun, X., Chen, K. J., Maddock-Carlin, K. R., Anderson, V. L., Lepper, A. N., Schwartz, C. A., ... Berg, E. P. (2012). Predicting beef tenderness using color and multispectral image texture features. Meat Science, 92, 386–393. Verbeke, W., Pérez-Cueto, F. J. A., de Barcellos, M., Krystallis, A., & Grunert, K. G. (2010). European citizen and consumer attitudes and preferences regarding beef and pork. Meat Science, 84, 284–292. Wu, J., Peng, Y., Li, Y., Wang, W., Chen, J., & Dhakal, S. (2012). Prediction of beef quality attributes using VIS/NIR hyperspectral scattering imaging technique. Journal of Food Engineering, 109, 267–273. Wulf, D. M., O'Connor, S. F., Tatum, J. D., & Smith, G. C. (1997). Using objective measures of muscle colour to predict beef longissimus tenderness. Journal of Animal Science, 75, 684–692. Wulf, D. M., & Wise, J. W. (1999). Measuring muscle color on beef carcasses using the L*a*b* color space. Journal of Animal Science, 77, 2418–2427. Young, O. A., & West, J. (2001). Meat color. In Y. H. Hui, W.-K. Nip, R. W. Rogers, & O. A. Young (Eds.). Meat Science and Applications (pp. 309). New York, NY: Marcel Dekker, Inc.
Janz, J. A. M., Aalhus, J. L., Dugan, M. E. R., & Price, M. A. (2006). A mapping method for the description of Warner–Bratzler shear force gradients in beef longissimus thoracis et lumborum and semitendinosus. Meat Science, 72, 79–90. Jeremiah, L. E., Tong, A. K. W., & Gibson, L. L. (1991). The usefulness of muscle color and pH for segregating beef carcasses into tenderness groups. Meat Science, 30, 97–114. Jones, S. D. M., Jeremiah, L. E., Tong, A. K. W., Lutz, S., & Robertson, W. M. (1991). The effects of marbling level, electrical stimulation, and postmortem aging on the cooking and palatability properties of beef rib-eye steaks. Canadian Journal of Animal Science, 71, 1037–l043. Koohmaraie, M., Seidemann, S. C., Schollmeyer, J. E., Dutson, T. R., & Crouse, J. D. (1987). Effect of post-mortem storage on ca++−dependent proteases, their inhibitor and myofibril fragmentation. Meat Science, 19, 187–196. Li, C., Li, J., Li, X., Hviid, M., & Lundström, K. (2011). Effect of low-voltage electrical stimulation after dressing on color stability and water holding capacity of bovine longissimus muscle. Meat Science, 88, 559–565. Lyford, C., Thompson, J., Polkinghorne, R., Miller, M., Nishimura, T., Neath, K., ... Belasco, E. (2010). Is willingness to pay (WTP) for beef quality grades affected by consumer demographics and meat consumption preferences? Australasian Agribusiness Review, 18, 1–17. Madruga, M. S., Elmore, J. S., Oruna-Concha, M. J., Balagiannis, D., & Mottram, D. S. (2010). Determination of some water-soluble aroma precursors in goat meat and their enrolment on flavour profile of goat meat. Food Chemistry, 123, 513–520. Mehaffey, J., Brooks, J., Rathmann, R., Alsup, E., Hutcheson, J., Nichols, W., ... Miller, M. F. (2009). Effect of feeding zilpaterol hydrochloride to beef and calf-fed Holstein cattle on consumer palatability ratings. Journal of Animal Science, 87, 3712–3721. Miller, M. F., Carr, M. A., Ramsey, C. B., Crockett, K. L., & Hoover, L. C. (2001). Consumer thresholds for establishing the value of beef tenderness. Journal of Animal Science, 79, 3062–3068. Moon, S. S., Yang, H. S., Park, G. B., & Joo, S. T. (2006). The relationship of physiological maturity and marbling judged according to korean grading system to meat quality traits of hanwoo beef females. Meat Science, 74, 516–521. Obuz, E., Dikeman, M. E., Grobbel, J. P., Stephens, J. W., & Loughin, T. M. (2004). Beef longissimus lumborum, biceps femoris, and deep pectoralis Warner–Bratzler shear force is affected differently by endpoint temperature, cooking method, and USDA quality grade. Meat Science, 68, 243–248. Peng, Y., & Wang, W. (2015). Application of near-infrared spectroscopy for assessing meat quality and safety. Infrared spectroscopy-harmonicity of biomolecules, crosslinking of polymers, food quality and medical applicationshttp://www.intechopen.com. Pflanzer, S. B., & de Felicio, P. E. (2011). Moisture and fat content, marbling level and color of boneless rib cut from Nellore steers varying in maturity and fatness. Meat Science, 87, 7–11.
49
Contents lists available at ScienceDirect
Meat Science journal homepage: www.elsevier.com/locate/meatsci
Bovine M. longissimus thoracis meat quality differences due to Canada quality grade J. Puentea, S.S. Samantab, H.L. Brucea, a b
T
⁎
Department of Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Building, University of Alberta, Edmonton, Alberta T6G 2P5, Canada Department of Electrical and Computer Engineering, Electrical and Computer Engineering Research Facility, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
A B S T R A C T
Differences in meat quality characteristics between the four Canada beef quality grades (Canada Prime, AAA, AA, and A) at days 4 and 18 post mortem were investigated using 48 (n = 12/grade) bovine M. longissimus thoracis (LT, rib eye). There was no difference in intramuscular fat content between Canada A and AA LT, and Canada AA LT had a higher mean Warner-Bratzler shear force (WBSF) than LT from all other grades (P = 0.0009) at day 18 post mortem. Canada Prime muscles were lighter and yellower than muscle from all other grades, and their increased lightness persisted with ageing. Mean cooking loss was lowest in Canada Prime LT and correlated with intramuscular fat content (r = −0.41 and − 0.29, days 4 and 18, respectively). Results confirmed differences in cooked product toughness can exist between the grades, with the potential for reduced tenderization in Canada AA LT.
1. Introduction Meat quality is the culmination of the acceptability of a meat product in terms of its colour, tenderness, juiciness, flavor and aroma (Madruga, Elmore, Oruna-Concha, Balagiannis, & Mottram, 2010; Renerre, 1982). In Canada, beef under thirty months of age that meets texture, muscling, fat and lean colour requirements is classified into four quality grades based upon the amount of intramuscular fat in the M. longissimus thoracis (LT; rib eye) muscle surface at the 12th and 13th rib interface. The Canada quality grades are: Canada A (traces of marbling); Canada AA (slight marbling); Canada AAA (small marbling); and Canada Prime (slightly abundant marbling) (Anonymous, 2007), and are synonymous with USDA Standard, Select, Choice and Prime grades respectively. Beef carcass grading allows for an estimation of the eating quality of beef and as a result this classification is used to set the value of the whole carcass as well. Although the Canadian beef grading system is used to set the value of the whole carcass, neither the true meat quality profile of each grade nor the meat quality differences among Canada grades were compared until recently. The most recent comparison of beef quality properties by beef grade was Puente, Samanta, and Bruce (2016), with prior examination conducted by Hawrysh and Berg (1976), while the effects of marbling level on cooking and palatability properties of beef rib-eye steaks was described by Jones, Jeremiah, Tong, Lutz, and Robertson (1991). In a study by Lyford et al. (2010), it was demonstrated that consumers were willing to pay additional money for increased beef eating quality especially in the Japanese market in a study that included Japan, the United States of
⁎
America (USA), Australia and Ireland. Also, in the same study, consumers were willing to pay 1.7 and 2.9 times the price for 4 and 5 star quality respectively, when 3 stars represented the “good everyday” quality, while consumers were willing to pay only half price for the 2 star product. Several studies have reported that meat tenderness is the most important quality trait for the consumer (Savell et al., 1987; Verbeke, Pérez-Cueto, de Barcellos, Krystallis, & Grunert, 2010) and have shown that consumers are willing to pay an increased price for guaranteed tender meat (Boleman et al., 1997; Miller, Carr, Ramsey, Crockett, & Hoover, 2001; Platter et al., 2003). Understanding which meat quality characteristics contribute to and affect tenderness is important, particularly the influence of intramuscular fat (marbling) because marbling score is the only parameter used to differentiate between the Canada quality grades. This study tested the null hypothesis that there is no difference in technological meat quality characteristics of the LT between the grades with the exception of intramuscular fat content and the concomitant changes to moisture and protein content. Therefore, the objectives of this study were to: 1) characterize the instrumental meat quality differences between the LT from the four quality Canada grades; and 2) understand the relationship between fat content and tenderness. 2. Materials and methods 2.1. Experimental design Twelve LT (rib eye) muscles from each quality grade (Canada A, AA,
Corresponding author. E-mail address: [email protected] (H.L. Bruce).
https://doi.org/10.1016/j.meatsci.2019.05.002 Received 31 October 2018; Received in revised form 29 January 2019; Accepted 1 May 2019 Available online 02 May 2019 0309-1740/ © 2019 Elsevier Ltd. All rights reserved.
Meat Science 155 (2019) 43–49
J. Puente, et al.
AAA & Prime) were obtained from a large Alberta abattoir at 3 days post mortem over four shipments. Personnel certified as meat graders by the Canadian Beef Grading Agency determined the quality grade of each carcass from which the muscles were derived within 24 h post mortem by viewing the surface of the M. longissimus thoracis muscle at the 12th and 13th rib interface. A total of 48 LT muscles were accepted into the study. From the posterior of each muscle portion (12th–13th rib interface), four 2.5 cm thick steaks were removed, with the first steak used for objective colour measurements, the second used for proximate analyses, the third for cooking loss and Warner–Bratzler shear force (WBSF), and the fourth for pH and drip loss. The remainder of the LT section was then stored at approximately 4 °C for an additional 14 days under vacuum. From the aged portion, steaks were removed from the posterior of the LT section, with the first steak removed used for objective colour measurements, the second steak used for cooking loss and Warner–Bratzler shear force, and the third steak used for pH and drip loss.
Table 1 Meat quality characteristics of beef M. longissimus thoracis from each of the Canada quality grades at 4 days post mortem. Analysis
n L* a* b* pH Drip loss (%) Cook loss (%) Cook Time (min/100 g) WBSF3 (Newton)
Canada grade A
AA
AAA
Prime
12 36.3a 18.5 2.9a 5.3a 0.8 17.2a 2.2a 42.6
12 36.8a 19.2 3.6a 5.3a 0.7 18.7a 2.4ab 44.9
12 35.9a 20.3 3.6a 5.4ab 0.6 15.9ab 2.4ab 45.0
12 39.4b 21.3 5.9b 5.5b 0.5 14.6b 2.6b 32.2
Pr > F1
SEM2
0.0006 0.0734 0.0022 0.0494 0.0567 0.0017 0.054 0.1240
0.88 1.15 0.80 0.04 0.29⁎ 0.70 0.12 4.28
a,b
Means with different superscripts within a row are significantly different at P < .05 according to least square mean differences tests. 1 Probability of the calculated F value with significance at P ≤ .05. 2 SEM - Standard error of the mean. 3 WBSF – Warner-Bratzler Shear Force.
2.2. Colour analysis Colour analysis is improved by increasing the number of measurements within a sample (Alcalde & Negueruela, 2001); therefore, 3 locations on the LT muscle surface were chosen at random for measurement. Colour values across the three measurements were averaged and the mean of each value recorded for statistical analysis. Prior to colour analysis, approximately 3 mm of the outside face was removed and the newly exposed surface was allowed to bloom (oxygenation) in a tray covered with oxygen-permeable polyvinyl-chloride film (Fisher Scientific, Pittsburgh, PA, USA.) at 4 °C for 60 min. Lightness (L*), green-red (a*) and blue–yellow (b*) were determined with a Minolta Chromameter CR-400 (Konica-Minolta, Osaka, Japan) using the colour system established by the Commission Internationale de L'Eclairage (CIE)(CIE, 1976). The instrument was calibrated before use against a white tile provided with the instrument.
cooled to < 10 °C in an ice bath and then weighed the next day after storage at about 4 °C. Cooking loss was calculated by dividing the steak weight loss during cooking by the raw weight of the steak and reported as a percentage of the initial raw weight. Cooking time was recorded every 3 min until steak internal temperature reached 71 °C using a fourchannel alarm timer (Traceable ®, Fisher Scientific, Edmonton, AB, Canada), and cooking time was calculated as minutes/100 g of fresh product. 2.5. Warner-bratzler shear force Cooked steaks were stored overnight at 4 °C, and the following day steaks were removed from refrigerated storage and allowed to reach room temperature. Once the cooked steaks reached room temperature, 6 cores of 1.27 cm diameter and 2 cm long were removed from each steak parallel to the muscle fibers using a cork borer. Each core was sheared once across the middle, perpendicular to the fiber direction, using a materials testing machine (AMETEK, Inc. Lloyd Instrument LRX plus, Digital Metrology Measurements, Kitchener, ON, Canada) fitted with a Warner–Bratzler type shear blade travelling at 225 mm/min. Shear force was expressed in Newtons (N) and values were averaged to obtain a mean value for each steak.
2.3. Intramuscular pH Measurements of pH were performed with a temperature-compensated pH meter (Fisher Scientific, Accumet Waterproof AP71 pH/mV/ Temperature, Fisher Scientific, Toronto, ON, Canada) fitted with a glass probe electrode (Hanna Instruments, Fisher Scientific, Toronto, ON, Canada) which was inserted into the muscle. Three readings were taken from each muscle and the pH values were averaged and the mean used for statistical analysis. Prior to pH measurement, the pH meter and electrode were standardized using commercial pH buffers of 4.0 and 7.0 at room temperature (23 °C).
2.6. Proximate analyses To determine the chemical composition of the beef samples, approximately 100 g of steak was cubed, weighed, placed into an aluminium tray, and lyophilized using a freeze dryer (Virtis freeze dryer ultra El-85, SP Scientific, Warminster, PA., USA). Upon the completion of lyophilisation, the trays were removed from the freeze dryer and final weights recorded for moisture loss calculation. Crude fat analysis was determined by pulverizing the freeze-dried sample into a fine powder using a blender fitted with a 1 L stainless steel container (Two-Speed Food Blender Model 7011G; Waring Commercial. Torrington, CT, USA) containing two to three pellets of dry ice. Duplicates of about 2 g each of this dry meat powder were placed in thimbles and analyzed for crude fat content (Method 960.39; Association of Official Analytical Chemists, 1995) by petroleum ether extraction (Goldfisch Fat Extraction Apparatus Model 35,001; Labconco Corp. Houston, TX, USA). A blank/ control sample was run at all times, and duplicates were averaged for statistical analysis. Nitrogen content was determined using triplicates of 100 mg of ground dry meat sample (Method 992.15; Association of Official Analytical Chemists, 1997) (Nitrogen/Protein Determinator CNS2000, Leco Corp., St., Joseph, MI., USA) and triplicates were averaged and means used for statistical analysis. Standardization and
2.4. Drip loss, cooking loss and cook time Drip loss was determined as described by Honikel (1998) and as outlined by the American Meat Science Association methods (AMSA, 1995). Drip loss was measured by first trimming the external fat from the LT steak where weights ranged from 106 to 200 g (Table 1). Trimmed steak samples were hung for 24 h at 4 °C in a closed plastic bag from a stainless steel hook. The weight of each trimmed steak portion was recorded before and after the procedure, and weight loss results expressed as a percentage of the original weight. To calculate cooking loss, additional LT steaks were trimmed of subcutaneous fat, weighed and grilled on a pre-heated grill (General Electric 4 in 1 Grill/Griddle, China) at 176 °C. The internal temperature of each steak was monitored continuously using a thermometer with a metal probe (Tinytag View 2 s, Interworld Electronics and Computer Industries Inc., West Vancouver, BC, Canada) inserted into the geometric centre of the steak. Steaks were heated until the steak internal temperature reached 71 °C. Once an internal temperature of 71 °C was reached, the cooked steaks were placed in a polypropylene bag and 44
Meat Science 155 (2019) 43–49
J. Puente, et al.
were the most yellow (b*) at day 4 post mortem (Table 1). There were no differences in a* values (coordinate green–red) among the grades regardless of additional ageing, although the mean value for the Canada Prime LT at day 4 post mortem approached significance for being the most red (P = 0.07). Mean b* values for the Canada Prime LT were greater than that of all other grades, which were not different from each other (Table 1), and in the steaks from the LT aged for an additional 14 days the difference in b* value between the Canada A and Prime LT approached significance (P = 0.06), with Canada A LT being the most blue and the Canada Prime LT being the most yellow. Mean intramuscular ultimate pH value for the 4 day post mortem samples was statistically greatest for the Canada Prime LT, which was not different from LT from Canada AAA carcasses (Table 1). In the portions that received an additional 14 days of ageing, however, there was no difference in the mean ultimate pH of the LT muscles across the grades (Table 2).
calibration prior to nitrogen analysis were performed with caffeine and ethylenediaminetetraacetic acid (EDTA) in triplicate prior to meat sample analyses. 2.7. Statistical analyses Data from non-aged (4 days) and aged (18 days) beef were analyzed in separate data sets due to ageing treatment being confounded with sample location along the LT. Data were organized as a randomized complete block design within day of ageing and analyzed using the MIXED procedure in the Statistical Analysis System (SAS) software (Version 9.2, Statistical Analysis Systems, Cary, NC, USA). Analysis of variance was conducted using beef grade as the sole fixed effect. Ribs were blocked by replicate and block was included as a random source of variation. Grade effect was considered significant at P ≤ 0.05 and, where grade was significant, least square mean differences were used to determine differences between grade means with significance at P ≤ 0.05. In all analyses of variance, degrees of freedom were corrected using the Kenward-Roger adjustment. Correlations were performed using PROC CORR to obtain Pearson correlations between the meat quality data to calculate linear dependence among variables. Correlation analyses were performed on drip and cooking loss percentages and steak weight to identify any dependence of drip and cooking loss percentages on steak weight. The randomized complete block design model was:
3.2. Drip loss, cooking loss and cook time Differences in drip loss between the grades approached significance (P = 0.057) with the Canada A day 4 post mortem LT steaks tending to have the most drip loss (Table 1). This tendency was not noted in the LT aged an additional 14 days, however, with these LT muscles showing no effect of grade on drip loss (Table 2). There were significant differences (P = .0017) within the day 4 post mortem LT due to grade for cooking loss, with Canada Prime LT having a lower mean cooking loss value than that of LT from all other grades (Table 1) with the exception of LT from Canada AAA carcasses, and this difference persisted in the aged samples (P = 0.02) (Table 2). Differences in cooking time for LT between the grades approached significance (P = 0.054) with the non-aged LT from the Canada Prime grade tending to require a longer time to reach 71 °C (Table 1). This tendency was not noted in the LT portion aged an additional 14 days, where the additionally-aged LT muscles showed no effect of grade on cooking time (Table 2).
yij = μ + Gi + Bj + εij. where μ was the overall mean, Gi was the grade codified with i = 1.0.4, Bj was the block where j = 1..0.12, and εij was the random deviation associated with each observation. Multiple regression analysis was performed relating meat quality measurements to peak WBSF using simple linear regression (PROC REG, SAS Version 9.2) with the stepwise selection function. Entry into the model was at P ≤ 0.05. Correlations between eligible measurements were determined using Pearson correlations (PROC CORR, SAS Version 9.2) prior to multiple regression analysis, and only measurements that were not correlated with each other were included in the regression.
3.3. Warner-bratzler shear force There were no differences in mean Warner-Bratzler shear force (WBSF) values between the grades in the day 4 post mortem LT (P = 0.12) (Table 1). Differences were found (P = 0.0009) in the LT portions aged an additional 14 days, with Canada AA LT having the highest and Canada AAA and Prime LT having the lowest WBSF values (Table 2).
3. Results 3.1. Colour and ultimate pH With and without additional ageing, LT steaks from Canada Prime carcasses had the highest mean L* values (Table 1 and Table 2) and
3.4. Proximate analyses Table 2 Meat quality characteristics of beef M. longissimus thoracis from each of the Canada quality grades at 18 days post mortem. Analysis
n L* a* b* pH Drip loss (%) Cook loss (%) Cook time (min/100 g) WBSF3 (Newton)
Canada grade
Pr > F1
SEM2
A
AA
AAA
Prime
12 33.2b 19.1 1.2 5.5 0.81 15.5a 2.1
12 32.6b 20.9 2.6 5.5 0.72 16.1a 2.0
12 31.8b 21.0 1.8 5.5 0.72 14.0ab 2.1
12 35.7a 21.1 3.1 5.6 0.69 12.7b 2.1
< 0.0001 0.4664 0.0611 0.3731 0.1906 0.0204 0.66
1.1 1.5 0.73 0.03 0.14⁎ 1.1 0.12
44.1a
52.6b
35.7c
39.6ac
0.0009
5.0
Proximate analyses were performed on day 4 post mortem LT muscle only. Differences in crude fat content between the grades were significant as anticipated (P < 0.0001), with the Canada Prime LT having the highest mean crude fat content (11.57%), followed by Canada AAA LT (4.62%). The lowest crude fat contents were observed in LT from the Canada AA (3.11%) and A grades (2.92%), the means of which were not significant different from each other (Table 3). Differences in moisture content were significant (P < 0.0001), with Canada Prime having the lowest moisture content (64.64%), lower than the mean moisture contents of LT muscles from the Canada AAA, AA and A grades, which were not different from each other (Table 3). Protein content varied by grade as well (P < 0.0001), with LT from the Canada A and AA having the highest mean protein contents and the LT from the Canada AAA and Canada Prime having the lowest protein contents (Table 3).
a,b
Means with different superscripts within a row are significantly different at P < .05 according to least square mean differences tests. 1 Probability of the calculated F value with significance at P ≤ .05. 2 SEM - Standard error of the mean. 3 WBSF – Warner-Bratzler Shear Force.
3.5. Pearson correlations For measurements performed at day 4 post mortem, there was no 45
Meat Science 155 (2019) 43–49
J. Puente, et al.
(P < 0.05). Cooking time was correlated to crude fat (r = 0.32) and moisture (r = −0.37)(P < 0.05), crude fat was correlated to moisture (r = −0.84) and protein contents (r = −0.65)(P < 0.0001), and moisture was correlated to protein (r = 0.35)(P < 0.05). For LT aged an additional 14 days, significant correlations were found (Table 7). L* was correlated to b* (r = 0.61, P < 0.0001) and crude fat (r = 0.32, P < .05) while a* was correlated to b* (r = 0.66, P < .0001), pH (r = −0.36) and Warner-Bratzler shear force (r = −0.45)(P < 0.05). Also, b* was correlated to pH (r = −0.28), drip loss (r = −0.29), cooking loss (r = 0.28), and protein content (r = −0.29)(P < .05). Intramuscular pH was correlated to crude fat (r = 0.35), drip loss was correlated to protein content (r = 0.29), and cooking loss was correlated to cooking time (r = 0.48), crude fat (−0.29) and moisture content (r = 0.41)(P < 0.05). Warner-Bratzler shear force and cooking time were correlated to protein (r = 0.32) and cooking time to protein content (r = −0.37)(P < 0.05). Crude fat was correlated to moisture (r = −0.84) and protein (r = −0.65) (P < 0.0001), while moisture was correlated to protein (r = 0.35) (P < 0.05).
Table 3 Means of proximate analyses from beef M. longissimus thoracis from each of the Canada quality grades. Analysis (%)
n Crude fat Moisture Protein
SEM2
Canada grade A
AA
AAA
Prime
Pr > F1
12 2.92 a 70.63 a 24.33 a
12 3.11 a 70.69 a 24.34 a
12 4.62 b 69.28 a 23.56 b
12 11.57 c 64.64 b 22.14c
< 0.0001 < 0.0001 < 0.0001
0.4879 0.8850 0.3493
a,b,c Means with different superscripts within a row are significantly different at P < 0.05 according to least square mean differences tests. 1 Probability of the calculated F value with significance at P ≤ 0.05. 2 SEM - Standard error of the mean.
Table 4 Pearson correlation coefficients between drip loss factors (at 4 and 18 days ageing combined) for beef M. longissimus thoracis from all Canada quality grades. Variable
Steak weight before (g)
Steak weight after (g)
Drip loss (g)
Drip loss (%)
Steak weight before (g) Steak weight after (g) Weight loss (g)
1.00
0.99 < 0.0001 1.00
0.47 < 0.0001 0.46 < 0.0001 1.00
−0.00 0.9340 −0.02 0.8360 0.86 < 0.0001 1.00
Drip loss (%)
0.99 < 0.0001 0.47 < 0.0001 −0.00 0.9340
0.46 < 0.0001 −0.02 0.8360
0.86 < 0.0001
3.6. Multiple regression Stepwise multiple regression analysis indicated that the a* value was the best and only predictor of WBSF value at both day 4 post mortem (P = 0.0002, partial R2 = 0.25)(Eq. (1)) and after an additional 14 days ageing (P = 0.0011, partial R2 = 0.21)(Eq. (2)). Partial R2 values indicated that the a* value described approximately 25 and 20% of the variation in WBSF at days 4 and 18 post mortem, respectively.
Table 5 Pearson correlation coefficients between cooking loss measurements for beef M. longissimus thoracis from each of the Canada quality grades (days 4 and 18 post mortem combined). Variable
Steak raw weight Steak trimmed weight Steak cooked Weight Steak weight loss
Steak raw weight
Steak trimmed weight
Steak cooked weight
Steak weight loss
Cook loss (%)
1.00
0.90 < 0.0001 1.00
0.85 < 0.0001 0.97 < 0.0001 1.00
0.68 < 0.0001 0.68 < 0.0001 0.50 < 0.0001 1.00
0.17 0.09 0.08 0.4007 −0.13 0.1781 0.77 < 0.0001
WBSF = 96.93891–2.56501(a∗value)
(1)
WBSF = 73.03827–1.39596(a∗value)
(2)
4. Discussion The Canadian beef quality grades are discerned by the degree of intramuscular fat or “marbling”, which is assessed subjectively during beef carcass grading by trained personnel and characterized as a visual marbling score. The effectiveness of this assessment was supported by the results of this study as there were differences in crude fat content of the beef from the various Canada quality grades, with the exception of the LT from Canada A and AA carcasses, which were not different. Puente et al. (2016) also found that the mean intramuscular fat contents of the LT from Canada A and AA carcasses were not different, and indicated that the sporadic occurrence of fat throughout the muscle may lead to over or underestimation of marbling in the muscle. This phenomenon has been reported by other researchers (Campion & Crouse, 1975), and suggests that an alternative to visual estimation of marbling may be warranted when low levels of intramuscular fat are present. Near-infrared spectroscopy is used to estimate fat content in ground and whole meats (Prieto, Roehe, Lavin, Batten, & Andrés, 2009), as it provides some level of penetration into the muscle, and so its application as a grading aid may warrant investigation. Intramuscular fat is subjectively assessed in the Canadian and USA beef grading systems most likely because it has been associated with favourable palatability, which has been attributed to improved product flavor (Corbin et al., 2015). Previous studies have shown that the degree of marbling has no effect on cooked product toughness (Jones et al., 1991; Puente et al., 2016), although Puente et al. (2016) found that intramuscular crude fat content was negatively correlated to WBSF before but not after 14 days of ageing. In the present study, there was no difference in mean shear force values due to Canada grade at 4 days post mortem, but LT from Canada AAA and Prime carcasses had lower mean WBSF values than LT from the other grades after 14 days additional ageing. Crude fat content was negatively correlated (r = −0.36)
significant correlation between the weight of trimmed steaks used for drip loss and the actual percentage of drip loss (P = 0.93) (Table 4). The linear correlation between steak weight and cooking loss, however, approached significance (P = 0.093) (Table 5). For day 4 post mortem LT, L* was correlated to b* (r = 0.39), cook time (r = 0.30), crude fat (r = 0.51), moisture (r = −0.45) and protein content (r = −0.31) (P < 0.05)(Table 6). For other colour coordinates, a* was correlated to b* (r = 0.41), Warner-Bratzler shear force (r = −0.50), and moisture (r = −0.45) and protein contents (r = −0.31)(P < 0.05). In addition, b* was correlated to drip loss (r = −0.34), cooking loss (r = −0.29), and fat (r = 0.40) and protein (r = −0.50)(P < 0.05) contents. Intramuscular pH was correlated to drip loss (r = −0.40), cooking loss (r = −0.35), crude fat (r = 0.49) and protein contents (r = −0.42), and drip loss was correlated to protein content (r = 0.32)(P < 0.05). Cooking loss was correlated to Warner-Bratzler shear force (r = 0.38), crude fat (−0.41), moisture (r = 0.29) and protein content (r = 0.43)(P < 0.05). Warner-Bratzler shear force was correlated to cook time (r = 0.33), crude fat (r = −0.36), moisture (r = 0.36) and protein contents (r = 0.29) 46
Meat Science 155 (2019) 43–49
J. Puente, et al.
Table 6 Pearson correlation coefficients between meat quality measurements performed on beef M. longissimus thoracis from all Canada quality grades at 4 days post mortem. Variable
L⁎
a⁎
b⁎
pH
Drip Loss (%)
Cook Loss (%)
WBSF1 (Newton)
Cook time (min/100 g)
Fat content (%)
Moisture content (%)
Protein content (%)
n L⁎ a⁎ b⁎ pH Drip loss (%) Cook Loss (%) WBSF (Newton) Cook time (min/ 100 g) Fat content (%) Moisture content (%) Protein content (%)
48 1.00 −0.05 0.39⁎ 0.27 −0.12 −0.18 −0.09 0.30⁎
48 −0.05 1.00 0.41⁎ 0.08 0.07 −0.08 −0.50⁎ 0.04
48 0.39⁎ 0.41⁎ 1.00 0.10 −0.34⁎ −0.29⁎ −0.03 0.23
48 0.27 0.08 0.10 1.00 −0.40⁎ −0.35⁎ −0.14 0.04
48 −0.12 0.07 −0.34⁎ −0.40⁎ 1.00 0.27 −0.19 −0.06
48 −0.18 −0.08 −0.29⁎ −0.35⁎ 0.27 1.00 0.38⁎ 0.11
48 −0.09 −0.50⁎ −0.03 −0.14 −0.19 0.38⁎ 1.00 0.33⁎
48 0.30⁎ 0.04 0.23 0.04 −0.06 0.11 0.33⁎ 1.00
48 0.51⁎ 0.27 0.40⁎ 0.49⁎ −0.27 −0.41⁎ −0.36⁎ 0.32⁎
48 −0.45⁎ −0.23 −0.21 −0.26 0.12 0.29⁎ 0.36⁎ −0.37⁎
48 −0.31⁎ −0.31⁎ −0.50⁎ −0.42⁎ 0.32⁎ 0.43⁎ 0.29⁎ −0.15
0.51⁎ −0.45⁎
0.27 −0.23
0.40⁎ −0.21
0.49⁎ −0.26
−0.27 0.12
−0.41⁎ 0.29⁎
−0.36⁎ 0.36⁎
0.32⁎ −0.37⁎
1.00 −0.84⁎⁎
−0.84⁎⁎ 1.00
−0.65⁎⁎ 0.35⁎
−0.31⁎
−0.27
−0.50⁎
−0.42⁎
0.32⁎
0.43⁎
0.29⁎
−0.15
−0.65⁎⁎
0.35⁎
1.00
WBSF – Warner-Bratzler Shear Force. P ≤0.05. ⁎⁎ P ≤0.0001. 1 ⁎
Table 7 Pearson correlation coefficients between meat quality measurements performed on beef M. longissimus thoracis at 18 days post mortem. Variable
L⁎
a⁎
b⁎
pH
Drip Loss (%)
Cook Loss (%)
WBSF1 (Newton)
Cook time (min/100 g)
Fat content (%)
Moisture content (%)
Protein content (%)
n L⁎ a⁎ b⁎ pH Drip loss (%) Cook loss (%) WBSF (Newton) Cook time (min/ 100 g) Fat content (%) Moisture content (%) Protein content (%)
48 1.00 0.26 0.66⁎⁎ −0.14 −0.05 0.15 −0.09 0.06
48 0.26 1.00 0.66⁎⁎ −0.36⁎ 0.06 0.18 −0.45⁎ 0.06
48 0.61⁎⁎ 0.66⁎⁎ 1.00 −0.28⁎ −0.29⁎ 0.28⁎ −0.15 0.26
48 −0.14 −0.36⁎ −0.28⁎ 1.00 −0.13 −0.12 0.11 −0.02
48 −0.05 0.06 −0.29⁎ −0.13 1.00 0.03 −0.06 −0.15
48 0.15 0.18 0.28⁎ −0.12 0.03 1.00 0.22 0.48⁎
48 −0.09 −0.45⁎ −0.15 0.11 −0.06 0.22 1.00 0.09
48 0.06 0.06 0.26 −0.02 −0.15 0.48⁎ 0.09 1.00
48 0.32⁎ 0.07 0.10 0.35⁎ −0.20 −0.29⁎ −0.19 0.06
48 −0.17 −0.05 0.07 −0.16 0.02 0.41⁎ 0.18 0.09
48 −0.27 −0.12 −0.29⁎ −0.15 0.29⁎ 0.04 0.32⁎ −0.37⁎
0.32⁎ −0.17
0.07 −0.05
0.10 0.07
0.35⁎ −0.16
−0.20 0.02
−0.29⁎ 0.41⁎
−0.19 0.18
0.06 0.09
1.00 −0.84⁎⁎
−0.84⁎⁎ 1.00
−0.65⁎⁎ 0.35⁎
−0.27
−0.12
−0.29⁎
−0.15
0.29⁎
0.04
0.32⁎
−0.37⁎
−0.65⁎⁎
0.35⁎
1.00
WBSF – Warner-Bratzler Shear Force. P ≤0.05. ⁎⁎ P ≤0.0001. 1 ⁎
were highest for the portion of the muscle farthest away from the 12th–13th rib interface. Shear force values before and after ageing may also be affected by the cooking method (Obuz, Dikeman, Grobbel, Stephens, & Loughin, 2004) as there is the potential for grilling equipment to cook differently between the ageing periods. After the additional 14 days ageing, WBSF analysis results indicated that the LT from Canada AAA carcasses had a lower mean WBSF value than LT from Canada A and AA carcasses, but similar to that from Canada Prime carcasses. This result suggested that Canada AAA LT had a greater capacity to tenderize than LT from the A and AA grades. Gruber et al. (2006) found that LT steaks containing high levels of intramuscular fat exhibited a greater decline in WBSF value with post mortem ageing, although Puente et al. (2016) did not. Puente et al. (2016) did find that the difference in mean WBSF values between LT steaks from Canada AAA and Prime carcasses and from Canada A and AA carcasses approached significance (P = .099), with Canada AA LT tending to have the highest mean WBSF value, and the WBSF results for the LT aged an additional 14 days in the present study agreed with this trend. Considering the effect of intramuscular fat content on not only toughness but colour is warranted because colour is one of the most important factors to influence customers during purchasing of meat (Hood & Riordan, 1973). The current study showed that, without an additional 14 days of ageing, LT from the Canada Prime grade had a
with Warner-Bratzler shear force at 4 days post mortem, but this correlation disappeared after 14 days additional ageing, suggesting that other factors were instrumental in the determination of cooked product toughness. Although not compared statistically, the mean shear force values for the LT aged an additional 14 days were unexpectedly higher than those measured at 4 days post mortem, in contrast to the literature that shows that meat tenderizes with time after animal exsanguination (Koohmaraie, Seidemann, Schollmeyer, Dutson, & Crouse, 1987). Means for WBSF before and after an additional 14 days ageing were not compared statistically because ageing treatment was confounded with position within the LT, with the steak from the portion aged an additional 14 days being farthest from the 12th–13th rib interface (approximately 5 in.) than the LT steak assessed for WBSF at 4 days post mortem. Randomization of samples from different muscle regions is warranted when comparing ageing treatments within the same muscle despite the existence of studies in which this is not considered (Mehaffey et al., 2009), as position would not then need to be considered as a source of variation between the ageing treatments. Steak location within the M. longissimus thoracis et lumborum may affect WBSF value, as Janz, Aalhus, Dugan, and Price (2006) found that LT steaks located close to the 12th–13th rib interface were tougher than those close to the shoulder (Janz et al., 2006). The results of the present study do not concur with those of Janz et al. (2006), as the mean WBSF values 47
Meat Science 155 (2019) 43–49
J. Puente, et al.
present study, the a* value accounted for about 25% of the variability in WBSF, with the proportion it was able to describe declining with time post mortem, suggesting that factors other than muscle pH or early post mortem temperature were most determinant of WBSF as time post mortem.
greater luminosity (L*) and yellowness (b*) than LT from the other Canada quality grades. Luminosity remained increased in the Canada Prime LT after an additional 14 days ageing, and the increased b* value of the Canada Prime LT relative to that of the LT from the other grades after the additional 14 days ageing approached significance as well. Puente et al. (2016) also noted an increase in yellowness with marbling that persisted with ageing, although no difference in luminosity was observed between the LT from the four quality grades. Lean L* and b* values at 4 and 18 days may have been increased in the Canada Prime LT by the large amount of intramuscular fat related to this grade, as increased lightness of lean has been related to warm muscle temperatures early post mortem (Bruce & Ball, 1990). Warm muscle temperatures early post mortem could arise from increased subcutaneous fat, which has been associated with carcasses that have high levels of marbling (Moon, Yang, Park, & Joo, 2006). An increased early post mortem temperature can denature muscle proteins, which can increase luminosity and yellowness either through structural alteration of the myofibrillar proteins (Sleper, Hunt, Kropf, Kastner, & Dikeman, 1983) or increased water exudation (Scopes, 1964; Scopes, 1970). That there were increased muscle temperatures in the Canada AAA and Prime carcasses was not verified in the present experiment, but is supported by significant positive correlations between intramuscular fat content and L* and b* values at day 4 post mortem (r = 0.51 and 0.40, respectively), and L* after the 14 days additional ageing (r = 0.32). The b* value after the 14 days additional ageing appeared to be more related to intramuscular pH than marbling, however, as it was negatively correlated to intramuscular pH (r = −0.28), indicating that as muscle pH decreased, yellowness increased after the additional 14 days of ageing. Previous studies have shown that meat colour darkens as intramuscular pH increases (Abril et al., 2001; Puente et al., 2016). In the present study, Canada Prime LT had the highest mean pH and the highest mean L* value, but there was no correlation between muscle pH and L*. As muscle pH increased, a* and b* values would decrease (r = −0.36 and − 0.28, respectively), suggesting darkening related to pH was due to a decrease in redness (increase in blueness) and a decrease in yellowness. This suggested that early post mortem cooling rate may have been more instrumental in muscle lean colour formation than intramuscular pH at the time of measurement (Bruce & Ball, 1990). The lean of Canada A and AA LT muscles may be darker than that of Canada Prime beef due to an increase in the oxygen consumption rate by post rigor beef muscle. The rate of oxygen consumption by beef is decreased by high early post mortem muscle temperature because inner mitochondrial membrane proteins and myoglobin are denatured (Young & West, 2001), and this contributes to an attractive bright red appearance of the exposed meat surface (Bendall & Taylor, 1972). These results suggest that the increased mean L* value of the Canada Prime LT was simply due to the level of intramuscular fat rather than the intramuscular pH. Wulf and Wise (1999) showed that marbling score was weakly but positively correlated to L* value (r = 0.26), as did Pflanzer and de Felicio (2011)(r = 0.34). As noted by Wulf and Wise (1999), the whiteness of intramuscular fat serves to lighten the colour of the muscle, as L* is described on a 0 (black) to 100 (white) axis scale. Colour has been found to be indicative of cooked beef toughness with some success (Peng & Wang, 2015; Sun et al., 2012; Wu et al., 2012) and has been found to be related to early post mortem temperature experienced by the muscle and the use of electrical stimulation (Bruce & Ball, 1990; Li, Li, Li, Hviid, & Lundström, 2011). In the present study, multiple regression analysis indicated that only a* value (redness) was related to WBSF. Wulf, O'Connor, Tatum, and Smith (1997) measured colour at 27 h post mortem and correlations between shear force and L*, a* and b* values were − 0.36, −0.24 and − 0.38, respectively, in that study. Jeremiah, Tong, and Gibson (1991) found that colour explained no > 48% of the variability in cooked beef toughness, and that muscle pH was more effective at predicting cooked beef toughness across the sexes (bulls, heifers and steers) than colour. In the
5. Conclusion This study indicated that LT muscles from Canada Prime and AAA had meat quality characteristics different from those of the other grades, suggesting that Prime and Canada AAA LT are appropriately valued as superior products. Canada A and AA had the lowest fat content of the four grades; therefore, the beef industry could potentially market these grades within consumer populations that express interest in low fat content meat products, although the potential for Canada AA LT to be tougher than the other grades even after ageing warrants consideration. Further research focussing on sensory characterization of beef from the various quality grades is needed so that a complete quality profile of Canadian beef can be achieved. Acknowledgements The authors gratefully acknowledge funding support from Alberta Livestock and Meat Agency, Alberta Innovates-BioSolutions (2009F143R), and the Natural Sciences and Engineering Research Council of Canada. The authors wish to thank staff of the University of Alberta Meat Protein Biochemistry Laboratory and the University of Alberta Agri-Food Discovery Place for excellent technical assistance. References Abril, M., Campo, M. M., Onenç, A., Sañudo, C., Alberti, P., & Negueruela, A. L. (2001). Beef color evolution as a function of ultimate pH. Meat Science, 58, 69–78. Alcalde, M. J., & Negueruela, A. L. (2001). The influence of final conditions on meat color in light lamb carcasses. Meat Science, 57, 117–123. American Meat Science Association (1995). Research guidelines for cookery sensory evaluation and instrumental tenderness measurements of meat. Chicago, IL: American Meat Science Association and National Livestock Meat Board. Anonymous (2007). Livestock and poultry carcass grading regulations (SOR/92–541). Retrieved January/15, 2013, from http://laws-lois.justice.gc.ca/eng/regulations/ SOR-92-541/. AOAC (1995). AOAC official method 960.39. Fat (crude) or ether extract in meat. Final action, AOAC official methods of analysis 1995. Arlington, VA: Association of Official Analytical Chemists. AOAC (1997). AOAC official method 992.15. Crude protein in meat and meat products including pet foods. Combustion method. First action 1992., AOAC official methods of analysis 1995. Supplement march 1997. Arlington, VA: Association of Official Analytical Chemists. Bendall, J. R., & Taylor, A. A. (1972). Consumption of oxygen by the muscle of beef animals and related species, II. Consumption of oxygen by post-rigor muscle. Journal of the Science of Food and Agriculture, 23, 707–719. Boleman, S. J., Boleman, S. L., Miller, R. K., Taylor, J. F., Cross, H. R., Wheeler, T. L., ... Johnson, D. D. (1997). Consumer evaluation of beef of known categories of tenderness. Journal of Animal Science, 75, 1521–1524. Bruce, H. L., & Ball, R. O. (1990). Postmortem interactions of muscle temperature pH and extension on beef quality. Journal of Animal Science, 68, 4167–4175. Campion, D. R., & Crouse, J. D. (1975). Predictive value of USDA beef quality grade factors for cooked meat palatability. Journal of Food Science, 40, 1225–1228. Commission International de l'Éclairage (1976). Official recommendations on uniform colour spaces. Colour Difference Equations and Metric Colour Terms. (Paris., Suppl. No. 2. CIE Publication No. 15 Colorimetry). Corbin, C. H., O'Quinn, T. G., Garmyn, A. J., Legako, J. F., Hunt, M. R., Dinh, T. T. N., ... Miller, M. F. (2015). Sensory evaluation of tender beef strip loin steaks of varying marbling levels and quality treatments. Meat Science, 100, 24–31. Gruber, S. L., Tatum, J. D., Scanga, J. A., Chapman, P. L., Smith, G. C., & Belk, K. E. (2006). Effects of postmortem aging and USDA quality grade on Warner-Bratzler shear force values of seventeen individual beef muscles. Journal of Animal Science, 84, 3387–3396. Hawrysh, Z. J., & Berg, R. T. (1976). Studies on beef eating quality in relation to the current Canada grade classifications. Canadian Journal of Animal Science, 56, 383–391. Honikel, K. O. (1998). Reference methods for the assessment of physical characteristics of meat. Meat Science, 49, 447–457. Hood, D. E., & Riordan, E. B. (1973). Discolouration in pre-packaged beef: Measurement by reflectance spectrophotometry and shopper discrimination. International Journal of Food Science & Technology, 8, 333–343.
48
Meat Science 155 (2019) 43–49
J. Puente, et al.
Platter, W. J., Tatum, J. D., Belk, K. E., Chapman, P. I., Scanga, J. A., & Smith, G. C. (2003). Relationships of consumer sensory ratings, marbling score and shear force value to consumer acceptance of beef strip loin steaks. Journal of Animal Science, 81, 2741–2750. Prieto, N., Roehe, R., Lavin, P., Batten, G., & Andrés, S. (2009). Application of nearinfrared reflectance spectroscopy to predict meat and meat products quality: A review. Meat Science, 83, 175–186. Puente, J., Samanta, S., & Bruce, H. L. (2016). Instrumental meat quality characteristics associated with aged m. longissimus thoracis from the four Canadian beef quality grades. Canadian Journal of Animal Science, 96, 143–153. Renerre, M. (1982). La couleur de la viande et sa mesure. Bulletin technique centre de recherches zootechniques Et Vétérinaires De Theix- INRA. Vol. 47. Bulletin technique centre de recherches zootechniques Et Vétérinaires De Theix- INRA (pp. 47–54). Savell, J. W., Branson, R. E., Cross, H. R., Stiffler, D. M., Wise, J. W., Griffen, D. B., & Smith, G. C. (1987). National Consumer Retail Beef Study: Palatability evaluations of beef loin steaks that differed in marbling. Journal of Food Science, 52, 517–519 (532). Scopes, R. K. (1964). The influence of post-mortem conditions on the solubilities of muscle proteins. Biochemistry Journal, 91, 201. Scopes, R. K. (1970). Characterization and study of sarcoplasmic proteins. In E. J. Briskey, R. G. Cassens, & B. B. Marsh (Eds.). Biochemistry and physiology of muscle as food. Madison: Univ. of Wisconsin Press. Sleper, P. S., Hunt, M. C., Kropf, D. H., Kastner, C. L., & Dikeman, M. E. (1983). Electrical stimulation effects on myoglobin properties of bovine longissimus muscle. Journal of Food Science, 48, 479. Sun, X., Chen, K. J., Maddock-Carlin, K. R., Anderson, V. L., Lepper, A. N., Schwartz, C. A., ... Berg, E. P. (2012). Predicting beef tenderness using color and multispectral image texture features. Meat Science, 92, 386–393. Verbeke, W., Pérez-Cueto, F. J. A., de Barcellos, M., Krystallis, A., & Grunert, K. G. (2010). European citizen and consumer attitudes and preferences regarding beef and pork. Meat Science, 84, 284–292. Wu, J., Peng, Y., Li, Y., Wang, W., Chen, J., & Dhakal, S. (2012). Prediction of beef quality attributes using VIS/NIR hyperspectral scattering imaging technique. Journal of Food Engineering, 109, 267–273. Wulf, D. M., O'Connor, S. F., Tatum, J. D., & Smith, G. C. (1997). Using objective measures of muscle colour to predict beef longissimus tenderness. Journal of Animal Science, 75, 684–692. Wulf, D. M., & Wise, J. W. (1999). Measuring muscle color on beef carcasses using the L*a*b* color space. Journal of Animal Science, 77, 2418–2427. Young, O. A., & West, J. (2001). Meat color. In Y. H. Hui, W.-K. Nip, R. W. Rogers, & O. A. Young (Eds.). Meat Science and Applications (pp. 309). New York, NY: Marcel Dekker, Inc.
Janz, J. A. M., Aalhus, J. L., Dugan, M. E. R., & Price, M. A. (2006). A mapping method for the description of Warner–Bratzler shear force gradients in beef longissimus thoracis et lumborum and semitendinosus. Meat Science, 72, 79–90. Jeremiah, L. E., Tong, A. K. W., & Gibson, L. L. (1991). The usefulness of muscle color and pH for segregating beef carcasses into tenderness groups. Meat Science, 30, 97–114. Jones, S. D. M., Jeremiah, L. E., Tong, A. K. W., Lutz, S., & Robertson, W. M. (1991). The effects of marbling level, electrical stimulation, and postmortem aging on the cooking and palatability properties of beef rib-eye steaks. Canadian Journal of Animal Science, 71, 1037–l043. Koohmaraie, M., Seidemann, S. C., Schollmeyer, J. E., Dutson, T. R., & Crouse, J. D. (1987). Effect of post-mortem storage on ca++−dependent proteases, their inhibitor and myofibril fragmentation. Meat Science, 19, 187–196. Li, C., Li, J., Li, X., Hviid, M., & Lundström, K. (2011). Effect of low-voltage electrical stimulation after dressing on color stability and water holding capacity of bovine longissimus muscle. Meat Science, 88, 559–565. Lyford, C., Thompson, J., Polkinghorne, R., Miller, M., Nishimura, T., Neath, K., ... Belasco, E. (2010). Is willingness to pay (WTP) for beef quality grades affected by consumer demographics and meat consumption preferences? Australasian Agribusiness Review, 18, 1–17. Madruga, M. S., Elmore, J. S., Oruna-Concha, M. J., Balagiannis, D., & Mottram, D. S. (2010). Determination of some water-soluble aroma precursors in goat meat and their enrolment on flavour profile of goat meat. Food Chemistry, 123, 513–520. Mehaffey, J., Brooks, J., Rathmann, R., Alsup, E., Hutcheson, J., Nichols, W., ... Miller, M. F. (2009). Effect of feeding zilpaterol hydrochloride to beef and calf-fed Holstein cattle on consumer palatability ratings. Journal of Animal Science, 87, 3712–3721. Miller, M. F., Carr, M. A., Ramsey, C. B., Crockett, K. L., & Hoover, L. C. (2001). Consumer thresholds for establishing the value of beef tenderness. Journal of Animal Science, 79, 3062–3068. Moon, S. S., Yang, H. S., Park, G. B., & Joo, S. T. (2006). The relationship of physiological maturity and marbling judged according to korean grading system to meat quality traits of hanwoo beef females. Meat Science, 74, 516–521. Obuz, E., Dikeman, M. E., Grobbel, J. P., Stephens, J. W., & Loughin, T. M. (2004). Beef longissimus lumborum, biceps femoris, and deep pectoralis Warner–Bratzler shear force is affected differently by endpoint temperature, cooking method, and USDA quality grade. Meat Science, 68, 243–248. Peng, Y., & Wang, W. (2015). Application of near-infrared spectroscopy for assessing meat quality and safety. Infrared spectroscopy-harmonicity of biomolecules, crosslinking of polymers, food quality and medical applicationshttp://www.intechopen.com. Pflanzer, S. B., & de Felicio, P. E. (2011). Moisture and fat content, marbling level and color of boneless rib cut from Nellore steers varying in maturity and fatness. Meat Science, 87, 7–11.
49