The Color of Beef at Different Times After Slaughter

pH value

Figure 3.11 shows that the pH value of the crossbred cattle groups decreased rapidly from 1 to 12 hours after slaughter, decreased slowly from 12 to 48 hours and reached the standard level after 48 hours. The results obtained on the pH value of crossbred beef in the experiment were consistent with the results of Honikel (1998)[142]

Muscle structure has a marked influence on the pH value of conventional meat.

6.8

6.6

6.4

6.2

5.8

5.6

5.4

5.2

1 hour

12 h

48 hours 8 days

Time after slaughter

Lai Sind

F1 (Bra x LS)

F1(Char x LS)

Figure 3.11. pH changes of beef

The pH value in living organisms is 7, after slaughter the pH gradually decreases to 5.5.

-5.7 is the suitable pH point for meat preservation.

In cattle with post-slaughter pH

o 5.8 - 6.0 meat has a dark color, high pH reduces the value of meat. Low pH from 5.2 - 5.5 is often found in meat with low water content, myoglobin oxidation is reduced, meat is often light red. Meat with an average pH of 5.5 - 5.7 will limit oxygen consumption, so the meat will retain a bright red color on the surface, the bright red color will increase the value of meat and attract consumers. When the pH is high 6.3 - 6.7 often uses a lot of oxygen so the meat is often dark red. The research results on pH of the long back muscle are consistent with the publication of Lawrence et al (2006) [109] when researching on Brahman cattle, the publications

of Cabareaux et al (2003)[139] study on BBB cattle.

Wulf et al (2002)[135] reported that normal beef is bright red in color with a pH value of 5.46, while beef is dark, dry and tough, with a pH of 6.03. The glycogen content in the muscle is related to the pH value and color of the meat. Meat with low glycolytic content has a high pH, the meat is usually dark in color, dry and less tasty.

Hocquette (1996)[97] showed that in beef, the pH changes within 48 hours after slaughter because the amount of glycogen in the muscle continues to decompose and produces lactic acid, which reduces the pH. When the amount of glycogen in the muscle has completely decomposed, the pH value will stabilize.

According to Do Duc Luc and Cs (2009)[30], the pH value of Vang and Lai Sind beef both changed in a decreasing direction from 1 hour after slaughter, decreased to the lowest at 48 hours and stabilized for 8 days. For Lai Sind beef, the pH at 1, 12, 48 hours and 8 days were 6.85; 6.03; 5.53 and 5.48 respectively.

Setthakul and Cs (2008)[123] showed that the 24-hour pH of meat in Thai local cattle, F 1 Brahman cattle, BP crossbred cattle and F 1 Charolais cattle were 5.65; 5.56; 5.58; 5.56, respectively. Our results are consistent with the publications of Cabareaux and Cs (2003)[139] when studying on BBB cattle, showing that the pH of BBB beef at 48 hours was 5.5. Realini and Cs ( 2005)[121] reported that Hereford beef 24 hours after slaughter had a pH value of 5.70. According to Apple and Cs ( 2006)[67], the initial pH value of the long back muscle is approximately 7.2 and then gradually decreases to 5.4 - 5.7 due to the accumulation of lactic acid in the muscle. The amount of lactate in the long back muscle increases, leading to a decrease in the pH value. The pH in the muscle is related to meat quality such as meat color, water retention, and meat toughness. Jaturasitha and Cs ( 2009)[101] showed that Thai beef slaughtered after 45 minutes and 24 hours had pHs of 6.83 and 5.52, respectively. This pH is equivalent to the pH of F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) cattle in the experiment.

3.3.3.2 Color of hybrid beef

The color of beef is related to the physical structure of the muscle fibers, the pH of the meat, and the amount of red fibers in the muscle, which is related to the iron content. The quality of the muscle pigment changes during storage. The fat content of the meat is related to the brightness of the meat. The meat of cattle fattened on concentrated feed in the barn is brighter in color than that of cattle raised on pasture.

Table 3.20. Color of beef at different times after slaughter

Target

Sind Lai (n = 5) Mean ± SE	F 1 (Bra × LS) (n = 5) Mean ± SE	F 1 (Char × LS) (n = 5) Mean ± SE
- L*(Lightness)
12 hours	33.75 0.32	32.99 0.80	34.65 1.04
48 hours	37.57 0.57	36.09 0.83	37.16 0.81
8 days	37.69 0.91	37.82 0.85	37.76 0.71
- a * (Redness)
12 hours	19.55 0.39	19.61 0.90	19.56 0.71
48 hours	21.29 0.34	21.76 0.70	22.01 0.67
8 days	22.11 0 .91	25.30 1.15	22.56 0.48
- b * (Yellowness)
12 hours	5.78 0.46	6.04 0.48	6.06 0.60
48 hours	7.85 0.36	8.27 0.41	8.27 0.57
8 days	8.57 0.72	9.98 0.68	8.60 0.36

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L* Brightness, a* Redness of meat, b* Yellowness of meat

The color of beef in the experiment is presented in Table 3.20, showing that after 12 hours of slaughter, the meat is dark red. At this time, the L* value of the tenderloin muscle in the Lai Sind, F 1 (Brahman  Lai Sind) and F 1 (Charolais  Lai Sind) cattle were 33.75; 32.99 and 34.65 respectively. The preservation process increased the L* value and by the 8th day, the values in the corresponding cattle were 37.69; 37.82 and 37.76. Besides the change in the L* value, the a* and b* values both increased, especially the sharp increase in the b* value, which changed the meat from dark red to bright red after 48 hours of slaughter.

Although the color values (L*, a* and b*) of meat did not differ between crossbred combinations at each time point (P > 0.05), the values changed over storage times, leading to changes in meat color (P < 0.05). For all types of cattle, the L*, a* and b* values tended to increase from time

12 to 48 hours (P < 0.05) and stable up to 8 days (P > 0.05).

Thus, we see that there is a relationship between the color and pH value of the tenderloin muscle. When the pH reaches a stable value, the color values no longer change.

Setthakul and Cs ( 2008)[123] showed that the L * values of loin muscle in Thai cattle, F 1 Brahman cattle, BP crossbred cattle, F 1 Charolais cattle gave L * values of 37.76; 35.01; 40.15 and 38.76 respectively. The corresponding a * values were 15.07; 16.05; 16.35; 21.49 and

b * values are 4.27; 5.07; 5.09; 8.55 respectively. Our research results

I about L * value in Lai Sind, F 1 (Brahman × Lai Sind) and F 1 (Charoalais × Lai Sind) are equivalent to the research results in Thailand on F 1 Brahman and F 1 Charolais cattle. Jaturasitha and Cs ( 2009)[101] said: Thai beef fattened with Panicum maxima and Stylosantthos guianensis grass has L * color value of 36.0; 37.4, respectively; a * value of 20.0; 19.6; b * value of 15.6; 15.7. The color values of F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) cattle are equivalent to these indicators compared to Thai beef.

According to Honikel (1998)[142], normal beef has an L* value between 35 - 40, while beef with an L* value = 28 is dark meat.

Studies by Clinquart et al. (1994)[81] showed that the L* value of the loin muscle after 48 hours of slaughter in Blanc-Bleu Bel cattle with genotypes BBBc, BBBm and Holstein cattle reached the corresponding values of 41.5; 37.90 and 37.7. Compared with the above studies, beef raised in Dak Lak had a lower L * value than Blanc-Blue Bel cattle with genotype BBBc and equivalent to genotype BBBm and Holstein cattle. The ratio of a*/b* values at 48 hours after slaughter in Blanc-Bleu Belge cattle with genotype

BBBc, BBBm and Holstein cattle were 1.4; 1.7 and 1.7 respectively while the a*/b* ratios of Sind crossbred cattle, F 1 (Brahman × Sind crossbred) and F 1 (Charolais × Sind crossbred) were 2.71; 2.63 and 2.66 respectively. The a * values of Sind crossbred cattle, F 1 (Brahman ×

Lai Sind) and F 1 (Charolais × Lai Sind) were higher than those in Clinquart's studies.

(1993)[80] showed that meat color values are related to breed factors and feeding process. Blanc - Blue Bel cattle fattened had a slaughter weight of 602 kg, so the accumulation of fat in the muscle was a factor that reduced the a * value and increased the b * value . The fattening weight of Lai Sind, F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) reached 317.80 kg; 343 kg and 362 kg respectively, not accumulating much fat in the muscle and this could be a trait that needs to be improved in our meat-oriented crossbred cattle. Clinquart and Cs (2000)[140] studied on Blanc Bleu Belge cattle fattened for 175 days and found that the meat color was bright red, L * value 42.6; a * value 17.0 and b * value 16.9. The L * value of beef color depends on age, Clinquart and Cs (2000)[140] showed that 24-month, 48-month and 72-month Blanc Bleu Bel cows had L * values of 39.5; 37.7 and 36.2 respectively. Lawrance and Cs (2006)[109] studying Brahman calves published L* values of the longus muscle in the range of 40.23 - 40.39.

The L * values of Sind crossbred cattle, F1 ( Brahman × Sind crossbred cattle) and F1 ( Charolais × Sind crossbred cattle) in our study were lower than the L * values of European meat-producing Bos taurus breeds and were comparable to the L * values of Bos indicus cattle .

The a * value is related to the red color of beef, in our experiment the a * value was higher than other beef breeds, which is also the reason for the dark red color of Lai Sind beef, F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind).

The b * value related to the yellow color of the beef in the experiment was lower than the b * value of specialized beef breeds such as Blanc Bleu Belge, Wagu, possibly due to the limited fat accumulation characteristics in the muscles (Marbling) of Lai Sind, F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) cattle. Therefore, the meat of the cattle in the experiment was often dark red when slaughtered.

3.3.3.3 Rate of water loss of meat during storage and processing

The results of the evaluation of the water loss rate of tenderloin in crossbred beef cattle groups during storage and processing are presented in Table 3.21. At 48 hours, the water loss rate of storage in Lai Sind beef, F 1 (Brahman × Lai Sind) and F 1 (Charolais

× Lai Sind) were 1.44%; 1.80% and 2.34% respectively, corresponding to 8 days 3.44%;

3.61% and 2.75%, no difference between the meat of the crossbred groups (P>0.05).

The processing dehydration rate at 12 hours after slaughter, Lai Sind, F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) was 28.12%; 28.45 and 27.20%, no difference (P>0.05). After 48 hours of storage, the processing dehydration rate in F 1 (Charolais × Lai Sind) cattle was the lowest (27.66%) followed by Lai Sind (31.48%) and the highest (33.49%) belonged to F 1 (Brahman × LaiSind), the difference was significant (P<0.05), respectively the processing dehydration rate after 8 days of Lai Sind, F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) was 35.76%; 34.48% and 34.29%, no difference between crossbred groups (P> 0.05). F 1 cows (Charolais

The F1 (Brahman × Lai Sind) had the lowest processing water loss rate at 48 hours compared to the Sind and F1 ( Brahman × Lai Sind), probably due to the fat accumulation characteristics in the muscle inherited from the Charolais breed, which is specialized for meat production, limiting the processing and storage water loss of this group of beef cattle.

The water holding capacity of beef is related to the quality and texture of beef. Dehydrated meat will be dry, tough, and lose its soft, sweet taste. Meat with interspersed fat will hold water better. Evaluating the water holding capacity of meat during storage and processing is an important indicator to improve the quality of beef.

Clinquart et al (2000)[140] showed that processing water loss at 8 days after storage in Blanc Bleu Belge cows aged 24, 48 and 72 months was 30%; 30.6% and 30.4%, respectively. The authors also found that beef fattened for different periods of time also had different water loss rates.

Table 3.21. Percentage of water loss at storage and processing times (%)

Target

Sind Lai (n = 5)

Mean ± SE

F 1 (Bra  LS) (n = 5)

Mean ± SE

F 1 (Char  LS) (n = 5)

Mean ± SE

Dehydration during storage

48 h

8 days

1.44 0.16 3.44 0.56	1.80 0.43 3.61 0.75	2.34 1.44 2.75 1.15
Dehydration during processing
12 h	28.12 1.09	28.45 1.24	27.20 1.70
48 h	31.48a 0.54	33.49a 0.25	27.66b 1.70
8 days	35.76 0.52	34.48 0.78	34.29 1.25

Note: In the same row, values with different letters are significantly different (P < 0.05)

Clinquart and Cs (1994)[81] studied purebred, crossbred and Holstein Blanc Blue cattle under the same feeding conditions and found that the processing water loss rates were 18.3%; 21.8% and 30.7%, respectively. The processing water loss rate was influenced by breeds and feeding processes.

The processing water loss rate of Lai Sind cattle, F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) in our experiment was higher than that of other authors when studying cattle specialized for meat production. In our opinion, breeding and feeding factors have a direct impact on this trait in beef cattle and this is also a trait that needs to be improved in the process of improving and feeding high-quality beef cattle.

Jaturasitha and Cs (2009)[101] showed that the storage water loss of Thai beef during storage was 4.32% - 5.14%; processing water loss was 32.54% - 32.84%. Compared with Thai beef, both of these indicators of F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) crossbred beef in the experiment were equivalent.

Do Duc Luc and Cs (2009)[30] research on Yellow cattle and Sind crossbred cattle

showed that the processing water loss rate at 8 days was 37.57% and 36.68%, respectively. Compared with this result, the crossbred beef cattle in the experiment had a lower processing water loss rate.

The results of water loss during storage and processing were similar to those published by Li and Cs (2006)[110] in a study on Chinese Yellow cattle but higher than those published by Lawren and Cs (2006)[109].

3.3.3.4 Tensile strength of the longus dorsi muscle

Table 3.22. Meat toughness at different times after slaughter (N)

Time after slaughter

Hybrid n = 5

Mean ± SE

F 1 (Bra  LS) n = 5

Mean ± SE

F 1 (Char  LS) n = 5

Mean ± SE

12 hours

76.20 1.18	72.30 1.46	72.89 0.88
48 hours	100.61a 2.05	101.85a 1.12	91.87b 1.48
8 days	83.35a 3.61	72.87b 4.13	71.27b 2.71

Note: In the same row, values with different letters are significantly different (P < 0.05)

The results of the study on meat toughness are presented in Table 3.22, showing that the beef of the crossbred groups in the experiment at 12 hours after slaughter, Lai Sind beef, F 1 (Brahman × Lai Sind) and F 1 (Charolais × Lai Sind) reached the corresponding toughness of 76.20 N; 72.30 N and 72.89 N. The toughness of the 3 groups of crossbred beef cattle 12 hours after slaughter did not differ between groups (P>0.05). The toughness of Lai Sind beef at 48 hours was 100.61 N; F 1 (Brahman  Lai Sind) 101.85 N and F 1 (Charolais  Lai Sind) 91.87 N, different between groups (P<0.05). The toughness of beef gradually increased and reached a maximum at 48 hours after slaughter due to muscle contraction after the animal died. Then this value gradually decreased, on the 8th day of storage the toughness decreased to Lai Sind beef 83.35 N; F 1 (Brahman  Lai Sind) reached 72.87 N and F 1 (Charolais  LaiSind) reached 71.27 N, the difference was significant (P<0.05). Phenomenon

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