The objective of this study was to investigate the effect of amino acid and vitamin C supplementation on the quality attributes of top round (TR) muscle from Korean cattle (Hanwoo). Sixteen-month-old steers were divided into three different feeding groups and raised until they were 28 months old. A control group (9 heads) was fed a basal diet and rice straw, whereas two experimental groups (8 heads/group) were fed a basal diet and rice straw supplemented with rumen-protected amino acids (≥16.0% L-lysine monohydrochloride, ≥8.0% DL-methionine) and vitamin C at a dose of 100 g/head/day (AA+VC group) or only vitamin C at 100 g/head/day (VC group). After slaughter, TR muscle (M. semimembranosus) was collected from carcasses and used to measure the quality attributes. Crude fat content was significantly higher (p<0.05) in the AA+VC group than in the VC group. No significant difference was observed for water-holding capacity and shear force value between the control, AA+VC, and VC groups. Contents of the free amino acids (FAAs) glycine, aspartate, and glutamate were significantly higher (p<0.05) in the VC group than in the control group. Sensory evaluation of tenderness and flavor preference revealed significantly higher scores (p<0.05) in the AA+VC group than in the control group. These findings suggest that vitamin C supplementation increases the contents of some FAAs, and the combined supplementation of amino acids and vitamin C improves the marbling and sensory attributes of TR muscle in Hanwoo.

본 연구는 홀스타인 거세육우(총 18두, 생후 4개월령, 체중 160kg)의 성장단계별 농산부산물 TMR 사 료의 에너지 수준(T1, TDN 75~84%; T2, TDN 77~85%)과 출하월령(18, 20 및 22개월)별로 배치하여 각 출하월령별 등심과 우둔육의 육질 및 관능특성을 조사하였다. 등심육의 경우 근내지방함량은 처리구 1은 22개월령 그룹이, 처리구 2는 20개월 및 22개월령 그룹이 유의적으로 가장 높았다(P<0.05). 우둔 육의 경우 처리구 1과 2가 모두 22개월령 그룹이 근내지방 함량이 가장 높았다(P<0.05). 처리구 2는 18개월령 그룹이 단백질 및 수분함량이 유의적으로 가장 높았다(P<0.05). 콜라겐 함량은 처리구 모두 출하월령간에 유의적인 차이가 없었다(P>0.05). 육질특성에서 등심육은 처리구 1의 경우 보수력, 전단 력, 가열감량, 육색에 있어서 급여기간 그룹간 유의적인 차이가 없었다(P>0.05). 처리구 2에서는 보수 력만 18개월과 20개월령 그룹이 가장 높았다(P>0.05). 우둔육은 처리구 1의 경우 보수력, 전단력, 가열 감량, 육색의 백색도에 있어서 급여기간 그룹간 유의적인 차이가 없었으며 단지 육색에서 적색도와 황 색도만 22개월령이 가장 높았다(P>0.05). 처리구 2의 경우 18개월령 그룹이 보수력이 가장 높았고 전 단력은 가장 낮았으며 가열감량은 18개월과 20개월령 그룹이 낮았다(P<0.05). 관능특성에 있어서 등심 육의 경우 처리구 1은 18개월과 20개월령이 연도점수가 높았고 20개월령 처리구가 향미 및 전반적인 기호도 점수가 유의적으로 높았다(P<0.05). 처리구 2는 연도, 다즙성, 향미 및 전반적인 기호도 점수 모두 20개월과 22개월령이 유의적으로 높았다(P<0.05). 우둔육의 경우 처리구 1은 연도가 18개월과 20 개월령이 유의적으로 높았고 전반적인 기호도는 20개월령이 유의적으로 높았다. 처리구 2는 18개월령 이 연도만 유의적으로 높았다(P<0.05). 결론적으로 홀스타인 거세육우는 농산부산물 TMR 사료를 22개 월령까지 급여한 그룹이 근내지방도는 높았으나 육질 및 관능특성은 18개월령 또는 20개월령이 더 우 수하였으므로 이러한 점을 고려하여 출하하는 것이 바람직할 것으로 생각된다.

본 연구의 목적은 육우 송아지 출하월령(3, 6, 9, 12개월) 조건에 따른 채끝등심(m. longissimus lumborum)과 꾸리육(m. tricep brachii)의 이화학적 육질 특성 및 지방산 조성에 미치는 특성을 비교하여 송아지고기의 상품성을 조사해 보고자 수행하였다. 채끝등심육과 꾸리육 모두 출하월령이 증가됨에 따라 수분 함량은 감소하였던(73.20~79.23%) 반면에 단백질(19.51~23.13%) 및 지방(0.76~1.99%) 함량은 증가하였다. 육색의 경우 두 부위 모두 출하월령이 증가됨에 따라 L*값(30.62~43.81)은 감소하는 반면에 a*값과 b*값은 증가하였다 (P<0.05). pH는 채끝등심육은 3개월령(5.96)이 꾸리육은 3개월(5.67) 및 6개월(5.73) 령이 다른 출하월령들 보다 유의적으로 높았다(P<0.05). 미오글로빈 함량은 채끝등심과 꾸리육 모두 출하월령이 증가할수록 증가하였다(P<0.05). 전단력을 측정한 경과 채끝등심육 은 3개월령(5.94 kg)과 12개월령(4.34 kg)이 6개월(9.16kg) 및 9개월령(9.57 kg) 보다 유의적으로 낮았으며, 꾸리육은 3개월령(2.83 kg)이 9개월 (4.47 kg)령 보다 유의적으로 낮았다(P<0.05). 가열감량은 채끝육의 경우 출하월령간에 유의적인 차이가 없었으나 꾸리육은 다른 출하월령들 보다 12개월(28.37%)령이 낮았고 3개월(36.55%)령이 높았다(P<0.05). 한편 채끝등심과 꾸리육은 모두 12개월령이 근절길이가 길었고 보수력이 유의적으로 높았다(P<0.05). 지방산 조성을 분석한 결과 채끝등심육은 3개월령에 C18:2n6, C20:1n9, 총 다가불포화지방산 (PUFA), 포화지방산에 대한 다가불포화지방산의 비율(PUFA/SFA) 및 오메가-6(ω-6) 지방산 함량이 유의적으로 높았고 12개월령에는 C16:1n7, C18:1n9, 총 단가불포화 지방산(MUFA), 총 포화지방산에 대한 총 단가불포화 지방산의 비율(MUFA/SFA) 지방산 함량이 유의적으로 높았다(P<0.05), 꾸리육의 경우 3개월령에 C20:1n9 함량이 높았고 12개월령에는 C14:0, C18:1n9, 총 단가불포화지방산(MUFA) 및 총 포화지방산에 대한 총 단가불포화 지방산의 비율(MUFA/SFA) 함량이 유의적으로 높았다(P<0.05).

Precise, rapid and simple methods for species identification in animals are among the most important techniques in the livestock industry and research fields including meat classification. In this study, polymerase chain reaction (PCR) based molecular identification using inter species polymorphisms were examined by PCR-restriction fragment length polymorphism (RFLP) analysis for mitochondrial DNA (mtDNA) cytochrome b (CYTB) gene sequences among four mammalian livestock animals (cattle, horse, goat and pig). The results from PCR-RFLP analysis using the AluI restriction enzyme were also provided for the species-specific band patterns among CYTB gene sequences in these four species. The AluI-digestion for CYTB genes provided interesting migration patterns differentially displayed according to each species. Cattle and horse had one AluI-recognition site at different nucleotide positions and their AluI-digested fragments showed different band patterns on the gels. Pig had two AluI-recognition sites within the amplified CYTB sequences and produced three bands on the gels. Goat had no AluI-recognition site and was located at the same position as the uncut PCR product. The results showed the species-specific band patterns on a single gel among the four livestock animal species by AluI-RFLP. In addition, the results from blind tests for the meat samples collected from providers without any records showed the identical information on the species recorded by observing their phenotypes before slaughter. The application of this PCR-RFLP method can be useful and provide rapid, simple, and clear information regarding species identification for various tissue samples originating from tested livestock species.

The objective of this study was to investigate meat quality and nutritional composition of 10 cuts (loin, striploin, chuck roll, chuck tender, short plate, brisket, bottom round, top sirloin, eye of round, and top round) from quality grade 1 beef from 11 Hanwoo steers at Hanwoo Experimental Station of National Institute of Animal Science. The protein contents were higher in top round (Udoon) and eye of round (Hongduke) and lower in loin (Dngsim) and short plate (Abjin) when compared to the other cuts (p<0.05). Whereas the intramuscular fat contents were highest in loin (12.51%), those were lowest in top round (4.14%) (p<0.05). The calories were higher in loin and short plate and lower in top round, chuck tender (Guri), top sirloin (Bosup), eye of round, chuck roll (Moksim), and bottom round (Sulgit) (p<0.05). The cooking loss (%) was 24.38% in loin and it was lower than the other cuts (p<0.05). The bottom round had higher water holding capacity (WHC) and chuck tender had lower WHC than those in the other cuts (p<0.05). In meat color, L* values were higher in loin and lower in top round than the other cuts (p<0.05). Total saturated fatty acid contents were higher in loin and lower in bottom round than the other cuts (p<0.05). In amino acid compositions, top round had significantly higher than those in the other cuts (p<0.05). The iron contents were higher in chuck tender and chuck roll contained higher iron contents than those of the other cuts (p<0.05). In conclusion, the meat quality and nutritional properties were significantly different among 10 cuts in the same quality grade of Hanwoo beef. Therefore, the provision of the meat quality and nutritional information of 10 cuts to consumers could be important for utilization and balanced consumption of different cuts.

The objective of this research was to evaluate the changes of water-soluble flavor precursors in loin and top round from Hanwoo (Korean cattle) beef during aging at 2℃ for 14 days. The glycogen, glucose and lactate contents were not significantly influenced by beef parts and aging. Among nucleotide-related compounds, inosine 5'-phosphate (IMP) and inosine contents were significantly (p<0.05) lower in loin compared with top round but hypoxanthine content was not significantly different between beef parts. Moreover, during aging, IMP content significantly (p<0.05) decreased while inosine and hypoxanthine contents significantly (p<0.05) increased. It is concluded that aging highly affected the nucleotide-related compounds among water-soluble flavor precursors in loin and top round from Hanwoo.

This study was conducted to investigate the effect of age on the oxidative stability of Hanwoo (Korean cattle) cow beef. The samples of M. longissimus dorsi from 65 and 133 months-old-Hanwoo cows (4 and 3 heads, respectively) were stored at 4±0.2℃ for 9 days. The proximate composition, total myoglobin content, pH value, water-holding capacity and drip loss were not significantly affected by age. At day 9 of storage, the lipid oxidation (2-thiobarbituric acid reactive substances) was significantly (p<0.05) higher in beef from 133 months-old-cows than 65 months-old-cows. Lower (p<0.05) oxymyoglobin concentration and R630-R580 value and higher (p<0.05) metmyoglobin concentration were observed in beef from 133 months-old-cows at day 9 of storage than 65 months-old-cows. The CIE a*, b* and C* values were significantly (p<0.05) lowered in beef from 133 months-old-cows at day 9 of storage than 65 months-old-cows. It could be concluded that old age decreased the lipid oxidation stability and myoglobin oxidation stability in Hanwoo cow beef.

The objective of this study was to investigate the influence of parity on chemical composition and meat quality of Hanwoo cows (n=74, 2-15 years old). The beef loin and top round muscle samples were obtained and divided by 3 groups of parity numbers (G1, 0; G2, 1-3; G3, 4-9 times). Loin and top round from G1 had significantly higher intramuscular fat contents and lower protein contents than those from G3 (p<0.05). There was no significant difference in collagen contents among 3 parity groups (p>0.05). In meat color, G1 was higher in a* values for loin and higher in L* and a* values for top round muscle (p<0.05). The loin from G1 had significantly lower cooking loss (%) than G3, however, there was no significant difference in water holding capacity among 3 parity groups. For top round muscle, G3 had significantly higher Warner-Bratzler shear force values and lower water holding capacity values than G1 (p<0.05). In fatty acid composition, G1 had significantly higher C18:1n7 and C18:1n9 contents for loin, and it had significantly higher C16:1n7 and C18:1n7 contents for top round than those of the other groups (p<0.05). In free amino acid composition, alanine was highest and followed by glutamine, phenylalanine, isoleucine, proline, glycine, methionine. In conclusion, the parity conditions influenced on chemical composition and meat quality depending on different cut of Hanwoo cows, and the parity numbers were related with the age of cows.

This study was carried out to investigate the effect of muscle part and aging period on free amino acids and aroma compounds of Hanwoo (Korean cattle) cow beef. The M. longissimus (ML) and M. semitendinosus (MS) from 101 mon-old-cows were aged at 2℃ for 14 d. The free amino acids concentration increased in both ML and MS on 14 d of aging. In ML, asparagine, glutamine, histidine, glycine, threonine, arginine, tyrosine, phenylalanine, isoleucine, leucine and lysine were significantly (p<0.05) higher than those in MS. Varieties of aldehydes, ketones, alcohols, hydrocarbons, nitrogen and sulfur compounds were detected in both ML and MS and majority of these compounds showed increasing trend on aging. The ML had higher 14 aldehydes (acetaldehyde, 2-methylpropanal, 3-methylbutanal, 2- methylbutanal, pentanal, hexanal, heptanal, E-2-heptanal, octanal, 2-octenal, 2-nonenal, E-2-decenal, E,E-2,4-decadienal and 2-undecenal), 5 ketones (2-propanone, 2,3-butanedione, 2-butanone, 2-heptanone and 2,3-octanedione), 4 alcohols (ethanol, 1-pentanol, 1-hexanol and 1-octanol), 3 hydrocarbons (3-ethyl-2-methyl-1,3-hexadiene, 3- methyldecane and 2,2-dimethyloctane) significantly (p<0.05) compared with MS. However, the MS had higher 5 nitrogen and sulfur compounds (methanethiol, dimethyldisulfide, fufural, 2,5-dimethylpyrazine and 2-octylfuran) significantly (p<0.05) compared with ML.

The study was conducted to investigate the differences in the compounds responsible for volatile flavors in Hanwoo and imported fresh beef from Australia, United States and New Zealand. Different imported beef samples were prepared as Angus beef from Australia, United States and New Zealand and the cross beef from the United States. Significant differences (p<0.05) in hexanal, benzaldehyde, octanal, nonanal, nonenal, decanal, E-2-decenal, hexadecyloxirane, tetradecanal, 2,2-dideutero octadecanal, octadecanal, pentadecane, 2,5-dimethyl pyrazine, 4-methyl-2-propyl-furan, 2-hexylfuran, 2-butylfuran, 2- pentylfuran, 2-heptyl furan were observed between loin and eye of round from Hanwoo and imported beef (p<0.05). In loin muscles, various volatile compounds such as hexanal, heptanal, octanal, E-2-octenal, nonenal, E-2-decenal, E,E,2,4-decadienal, 2-undecenal, heptane, 2-butyl furan were found to be significantly higher in Hanwoo beef as compared to imported beef. However, in the round muscles of Hawnoo eye compounds that were observed to be significantly higher were pentanal, hexanal, heptanal, benzaldehyde, octanal, nonanal, E-2 -decenal, octadecanal, 2-furan methanol and 2-pentyl furan. Further study need to be determined if those volatile compounds can be used as a bio-marker to identify origins of beef.