• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.47-51
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• 2015

This study was conducted to make certain that the intramuscular fat score at 13th rib could represent the fat content of whole loin from Hanwoo in Korea beef grading system. A total 42 loins from 23 carcasses of grade $1^{{+}{+}}$, 16 carcasses of grade $1^+$, and 3 carcasses of grade 1 of Hanwoo were used for this study. The crude fat content and intramuscular fat score at the $1^{st}$, $6^{th}$, and $13^{th}$ rib, and the last lumbar position of loin were measured. The crude fat content was the highest at the $6^{th}$ rib of loin from the carcasses of grade $1^{{+}{+}}$ and $1^+$ (p<0.05). There were no significant difference of the intramuscular fat scores measured by image analysis and beef marbling score (BMS) between the 6th and $13^{th}$ rib of loin from the carcasses of $1^{{+}{+}}$ and $1^+$ and that were significantly higher than intramuscular fat scores at the $1^{st}$ rib and the last lumbar position of the loin. From the results, we conclude that the intramuscular fat score at the $13^{th}$ rib can represent the fat content of loin when meat graders decide the grade of Hanwoo carcass.

• Food Science of Animal Resources
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• v.29 no.6
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• pp.726-735
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• 2009

This study was conducted to investigate the Warner-Bratzler shear force (WBS), sarcomere length, total collagen contents and consumer tests of different cuts of Hanwoo beef based on quality grade. Five cuts [Cheggt (striploin), Dngsim (loin), Moksim (chuck roll), Udoon (top round), Yanggi (brisket)] were obtained from Hanwoo beef (bulls and steers, 24-30 months old) and grouped by their quality grades ($1^{++}$, $1^+$, 1, 2 and 3). The WBS values of chuck cut in $1^{++}$, $1^+$ and 1 quality grade groups were 5.47 (kg/0.5 $inch^2$), 5.46 (kg/0.5 $inch^2$) and 6.54 (kg/0.5 $inch^2$), respectively, which were significantly lower than those of chuck in quality grade 3, which was 8.41 (kg/0.5 $inch^2$) (p<0.05). The sarcomere length of the quality grade groups were significantly longer for brisket (3.72 ${\mu}m$) of $1^{++}$ quality grade than for that of 3 quality grade brisket (p<0.05). Brisket of $1^{++}$ and 2 quality grade had significantly greater sarcomere lengths than strip loin and top round in the same quality grade (p<0.05). The total collagen contents of strip loins in the $1^{++}$, $1^+$, and 1 quality grade groups (1.17, 1.18 and 1.14 g/100 g, respectively) were significantly lower than those of the 3 quality grade group (1.63 g/100 g) (p<0.05). The overall sensory scores of tenderness and juiciness for the five cuts of $1^{++}$ quality grade were significantly higher than those of the other quality grade (p<0.05). Among the five cuts, loin had the highest tenderness and juiciness scores (p<0.05), whereas top round had the lowest tenderness and juiciness scores (p<0.05). Overall, there were significant differences in the WBS and sensory properties among quality grades and cuts (p<0.05). However, the sarcomere length and total collagen contents of chuck roll, top round and loin did not differ among quality grades.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.591-595
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• 2002

Three hundred thirty five progeny testing steers of Korean beef cattle were evaluated ultrasonically for back fat thickness (BFT), longissimus muscle area (LMA) and intramuscular fat (IF) before slaughter. Class measurements associated with the Korean yield grade and quality grade were also obtained. Residual standard deviation between ultrasonic estimates and carcass measurements of BFT, LMA were 1.49 mm and $0.96cm^2$. The linear correlation coefficients (p<0.01) between ultrasonic estimates and carcass measurements of BFT, LMA and IF were 0.75, 0.57 and 0.67, respectively. Results for improving predictions of yield grade by four methods-the Korean yield grade index equation, fat depth alone, regression and decision tree methods were 75.4%, 79.6%, 64.3% and 81.4%, respectively. We conclude that the decision tree method can easily predict yield grade and is also useful for increasing prediction accuracy rate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1288-1292
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• 1999

The physicochemical properties and palatability of Hanwoo(cow, steer, and bull) beef loin(1＋ carcass grade) were studied. pH(5.56~5.69), moisture content(67.6~69.0%), crude protein content(17.8~18.7%), and crude fat content(11.9~13.8%) of Hanwoo beef loin did not show significant difference between the types of Hanwoo. L(44.5~46.9), a(19.9~20.6), and b(10.3~11.6) color parameters, water holding capacity (69.4~70.5%), volatile basic nitrogen content(9.86~11.28mg%), thiobarbituric acid value(0.148~0.158 mg malonaldehyde/kg), and cooking loss(26.3~27.9%) of beef loin did not show significant difference between the types of Hanwoo either. Hardness, myofibrillar fragmentation index(MFI), and chewiness of beef loin were 6.1~6.9 dyne/cm2, 50.3~54.9, and 39.5~ 52.0g, respectively. No differences were found in hardness and MFI between the types of Hanwoo, while chewiness of cow was much lower than that of steer and bull(p<0.05). Cow was the best in palatability.

• Food Science of Animal Resources
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• v.42 no.2
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• pp.240-251
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• 2022

Fat deposition in animal muscles differs according to the genetics and muscle anatomical locations. Moreover, different fat to lean muscle ratios (quality grade, QG) might contribute to aroma development in highly marbled beef. Scientific evidence is required to determine whether the abundance of aroma volatiles is positively correlated with the amount of fat in highly marbled beef. Therefore, this study aims to investigate the effect of QG on beef aroma profile using electronic nose data and a chemometric approach. An electronic nose with metal oxide semiconductors was used, and discrimination was performed using multivariate analysis, including principal component analysis and hierarchical clustering. The M. longissimus lumborum (striploin) of QG 1++, 1+, 1, and 2 of Hanwoo steers (n=6), finished under identical feeding systems on similar farms, were used. In contrast to the proportion of monounsaturated fatty acids (MUFAs), the abundance of volatile compounds and the proportion of polyunsaturated fatty acids (PUFAs) decreased as the QG increased. The aroma profile of striploin from carcasses of different QGs was well-discriminated. QG1++ was close to QG1+, while QG1 and QG2 were within a cluster. In conclusion, aroma development in beef is strongly influenced by fat deposition, particularly the fat-to-lean muscle ratio with regard to the proportion of PUFA. As MUFA slows down the oxidation and release of volatile compounds, leaner beef containing a higher proportion of PUFA produces more volatile compounds than beef with a higher amount of intramuscular fat.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.1064-1075
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• 2021

Recently, a high level of dietary crude protein (CP) has become of interest as a possible practice to improve the carcass quality of beef cattle, and its level has been increasing in the field. However, there is little scientific evidence that supports this. This study was conducted to test whether a high dietary CP level would improve growth performance, body metabolism, and carcass traits in Hanwoo beef cattle. A total of 32 Hanwoo finishing beef cattle (18 multiparous cows, six heifers, and eight steers) participated in a 12-weeks feeding trial. Two kinds of total mixed rations were prepared to contain two different CP; 156 g/kg for the control (CON) and 173 g/kg of CP for the treatment (HCP), while maintaining a similar level of metabolizable energy. The experiment was ended when more than half of the steers reached the target body weight (730 kg). Blood was collected at the end of the experiment. After harvesting, the carcass trait was evaluated at the slaughterhouse according to Korean standards. The carcass yield score and grade were also calculated based on revised criteria. Overall, dry matter intake, average daily gain, blood metabolites concentration, and the carcass traits, except for backfat thickness and the yield score, did not differ between the treatments. The HCP had lower backfat thickness than those of CON. There was no difference in the carcass yield grade, but the yield score was higher in the HCP treatment. According to the newly revised carcass grading criteria, both yield score and grade were higher in HCP than in CON. Increasing CP supply decreased the carcass's backfat thickness without altering growth performance and body metabolism, resulting in improved yield score and grade. Therefore, feeding a high CP diet may be beneficial in the farm income, although it may also increase feed cost and nitrogen excretion to the environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.537-544
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• 2020

Beef consumption trends are changing according to consumer needs and preferences. This study was conducted to collect the fundamental information by investigating the consumer's preference and purchase propensity of beef(Hanwoo beef) for improvement of Korean beef grading system. Consumers were recruited from Seoul, Gyeonggi-do, and 5 metropolitan cities, and surveyed from July 24 ~ August 14, 2017. The data obtained from 362 consumers were finally selected for the verification process. Results from the Hierarchical Regression Analysis reveal that the increased purchasing frequency is positively correlated with the following factors, in the consumer group showing preference in the Quality Grade (QG) of beef: marbling type 1QG, fat color 1⁺QG, and income, grade opinion, marbling contents and type 1⁺⁺QG. Conversely, no factor affected the increased purchasing frequency in the consumer group having no preferred QG for beef (p>0.05). Our study determined significant differences in the factors affecting increased purchase frequency of beef among the different groups, classified depending on their preferred QG. The grading system is important since it directly correlates with profit for livestock farmers and the industry. We therefore propose that the grading criteria need to be revised reasonably but scientifically, considering various opinions of the producers and consumers.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.215-223
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• 2005

The bacteria on the surface of slaughtered meat was monitored to investigate the relationships between microbiological quality and sanitation management in slaughter process of cattle and pig. It was conducted to evaluate the microbiological quality on the surface of slaughtered beef and pork in Seoul from January to December 2004. Two hundred and thirty three beef and 233 pork carcasses were surveyed on generic E coli counts and standard plate count for microbiological quality and Salmonella spp, Listeria monocytogenes, Staphylococcus aureus, Clostridium perfringens and E coli O157: H7 as pathogenic microorganisms. The prevalence of the excellent or good grade $(10^4\;CFU/cm^2)$ in beef and pork carcasses were $100\%\; and\;99.2\%$, respectively. The frequency of beef carcasses with less than $10^2\;CFU/cm^2$ of generic I coli counts was $100\%$, while that of pork carcasses was $99.6\%$. Of 233 beef carcasses, $1(0.42\%)$ was contaminated with L monocytogenes and $6(2.58\%)$ with C perfringens. Of 233 pork carcasses, $11(4.72\%),\;2(0.86\%),\;and\;2(0.86\%)$ were contaminated with L monocytogenes, C perfringens, and S aureus, respectively, Salmonella spp and E coli O157:H7 were not detected with all of the beef and pork carcasses. In conclusion, this study emphasized the Importance of relationship between microbiological quality and sanitation management in slaughter process of cattle and pig, in abattoirs.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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• pp.157-165
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• 2020

Objective: The objective of this study was to compare the quality of dry-aged beef from cull Hanwoo cows slaughtered at 60 or 80 months old. Methods: A total of eight cull Hanwoo carcasses with a quality grade of 3 (low-grade) were selected and divided into two age groups: 63.5±2.5 months old (n = 4) and 87.8±4.5 months old (n = 4). Whole longissimus thoracis et lumborum from the 11th rib to the last lumbar vertebrae, including the back fat, was removed from the carcass at 24 h postmortem and aged for 50 days in darkness at a temperature of 2℃±1℃, a relative humidity of 85% and an air flow of 2 m/s. The sampling was performed aseptically after 0, 20, 24, 40, and 50 days of aging. Results: Regardless of the aging period, aging increased the lightness (p<0.05), redness (p<0.05) and yellowness (p<0.05) at initial blooming (90 min after slicing) and the overall acceptance (p<0.05). No further tenderization effect was found after 20 days of aging, but aging for 50 days significantly increased the lipid oxidation (p<0.05). The generation of aroma volatiles in the roast steak from aged samples was higher (p<0.05) than that of non-aged samples. No significant effect of age at slaughter was found on the color, pH, water-holding capacity, cooking loss, shear force value, bacterial counts, volatile basic nitrogen, consumer acceptance, lipid oxidation, fatty acid composition or aroma volatiles. Conclusion: The quality of dry-aged beef obtained from cull Hanwoo cows slaughtered at either 60 or 80 months old with similar quality grade was comparable and extending dry aging for more than 40 days is not recommended considering the costs and further lipid oxidation.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.321-327
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• 2010

The effect of cattle sex (cow, bull, and steer) on carcass traits of quality grade factors, physicochemical, and sensory traits of Longissimus Dorsi in Hanwoo was evaluated. Carcass traits of 42,113 heads were collected nation-wide and 257 heads were slaughtered to analyze beef quality. Sex affected significantly marbling score, meat color, fat color, texture, maturity, and quality grade of Hanwoo (p<0.05). Hanwoo steer carcasses had the highest marbling score (5.02), maturity (2.17), and texture (1.31) than those of cows and heifers. Crude fat of steers was higher than that of other cows and bulls. Steers showed the highest $L^*$(39.01), Warner-Bratzler shear force (4.03 kg), and water holding capacity (57.08%), however, there was no significant differences between those of cows and bulls. Ultimate$pH_{24}$ was shown difference among sex (5.58-5.69), however, the values remained within normal range. In sensory evaluation analyses, sex affected significantly tenderness, juiciness, and flavor (p<0.05). Also, the over all acceptability of steer beef was significantly higher than that of cow and bull beef. These results could be used as fundamental data set for further research activities to elevate Hanwoo beef qualities (p<0.05).