본 연구에서는 거세방법에 따른 한우의 안심살(M. psoas major), 꽃등심살(M. longissimus thoracis) 및 우둔살(M. semimembranous)의 육질특 성과 지방산 조성을 조사하였다. 공시시료는 송아지가 7개월령에 도달하면, 외과적 수술방법을 통해 한쪽 고환을 제거한 반거세 한우(half-castration; HC) 9두와 양쪽 모두 제거한 완전거세 한우(complete-castration; CC) 8두를 이용하였다. 거세된 송아지는 24-26개월까지 동일한 조건에서 사육한 후 도축하고 3개 부위(안심살, 꽃등심살, 우둔살)를 채취하여 육질 분석하였다. 거세방법에 따른 그룹 간 지방함량은 HC 그룹이 2.97~11.06%로 CC 그룹보다 낮은 함량을 나타내었으며, 수분함량은 HC 그룹이 65.39~70.90%로 CC 그룹보다 높은 함량을 나타내었다(p<0.05). 3개 근육의 pH는 5.47~5.54 범위였으며, pH와 보수력은 거세방법에 따른 유의적인 차이는 나타나지 않았다(p>0.05). 육색은 L*값과 a*값에서 HC가 CC보다 낮게 나타났다(p<0.05). 가열감량과 전단력은 HC 그룹의 꽃등심살이 CC 그룹보다 높은 값을 나타내었다(p<0.05). 지방산 조성은 palmitic acid, palmitoleic acid, vaccenic acid, oleic acid, linoleic acid, linoleneic acid와 PUFA, n6에서 HC와 CC 그룹 간 유의적 차이가 나타났다(p<0.05). 특히, 지방산 조성에서 HC 그룹과 CC 그룹 모두 oleic acid가 가장 높은 함량을 나타내었다(p<0.05). 따라서 거세 방법은 한우육의 근육 내 지방, 육색, 연도와 같은 이화학적 특성과 지방산 조성에 영향을 미칠 수 있다고 사료된다.

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.

The influence of aging on the flavor precursors and volatile compounds of top round beef was studied. The concentrations of free amino acids, nucleotides, creatine, dipeptides, and volatile compounds were measured after top round from Hanwoo was aged at 4℃ for 21 days. The amount of free amino acids in top round significantly increased with the increase of aging period. There was no effect of aging on the concentrations of adenosine monophosphate or inosine in top round. The inosine monophosphate content of top round significantly decreased with age, while the hypoxanthine content increased. The concentrations of creatine, carnosine, and anserine in top round were not influenced by aging. In total, 24 volatile compound were identified in aged, cooked top round. Of these, the quantities of aldehydes (propanal, pentanal, hexanal, heptanal, octanal, and nonanal), hydrocarbons (pentane and octane), 2-butanone, ethyl acetate, and pyridines (4-ethynyl-pyridine and 4-acetyl-pyridine) significantly increased after aging. We conclude that the flavor of top round can be improved by aging.

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.

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.