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식육을 냉동한 후, 해동하여 냉장저장하면 육색이 빨리 저하되는 원인을 구명하고자 사후 24시간의 돈육 등심을 냉장(대조구), 냉동과 해동 1회 및 2회(처리구)로 구분하여 7일간 냉장저장하면서 표면육색, 육색소와 지방산화도, HADH 활성도, 육즙 감량, 육색소 함량 및 근장단백질 함량의 변화를 조사하였다. 그 결과 처리구가 대조구에 비해 육색이 빨리 어두워지고 옅어지는 것으로 나타났으며 MetMb의 형성도 촉진되는 것으로 나타났다. 하지만 지방산화도는 대조구와 Table 4. Changes in drip loss (%), myoglobin and sarcoplasmic protein contents of pork loin during cold storageTreatment1)Cold storage daysBefore freeze1 day3 day7dayDrip loss(%)C-6.78±1.85Ba7.89±1.42Aa10.45±0.20BbT1-10.51±1.71AB12.08±3.93B13.36±2.13ABT2-13.93±0.15B14.69±0.94B15.52±0.23BMyoglobin content(mg/g)C1.25±0.03Ba1.23±0.01a1.24±0.08Aa1.08±0.05bT11.08±0.01Ca1.12±0.05a1.13±0.03ABa1.01±0.15aT21.29±0.01Aa1.13±0.13b1.08±0.09Bb1.02±0.03bSarcoplasmicprotein(mg/g)C75.73±4.1774.87±3.5674.20±3.1973.65±2.04AT175.20±4.01a74.53±3.55a73.28±3.84b67.55±4.13BbT276.00±4.2075.37±3.3074.15±3.6371.15±2.83AB1) C : storage in refrigerator at 4℃ without freeze.T1 : storage in refrigerator at 4℃ after freeze-thaw one cycle. T2 : storage in refrigerator at 4℃ after freeze-thaw two cycle.A~C : Means ±SD with difference superscript in the same column are significantly different(p<0.05).a,b : Means ± SD with difference superscript in the same row are significantly different(p<0.05).


To investigate the effect of β-hydroxyacyl CoA-dehydrogenase(HADH) activity increased by freezed and thaw process on myoglobin(Mb) oxidation without lipid oxidation during, pork loins were collected at postmortem 24 hrs and sliced to steaks (3 cm thickness). Samples were packaged in a polyethylene bag and subjected to fresh group (control), one cycle freezed and thaw group (treatment 1) and two cycles freezed and thaw group (treatment 2), respectively. Samples were measure meat color (CIE L*, a*, b*), the contents(%) of MetMb, thiobarbituric acid reactive substance (TBARS) value and HADH(β-hydroxyacyl CoA-dehydrogenase) activity at 0, 3, and 7 days of storage at 4℃. Both treatments showed significantly (p<0.05) lower L* and higher L* value compared to those of control at 7 days. On the contrary, MetMb contents(%) of treatments were significantly (p<0.05) higher than those of control during cold storage. However there were no significant (p> 0.05) differences in TBARS values between control and treatments during 7 days. There were significant (p<0.05) differences in HADH activity between control and treatments at 3 days of cold storage. Both treatments showed higher HADH activity compared to those of control. These results suggested that the freezed and thaw process could accelerate meat color deterioration, i.e. increased MetMb percentage without lipid oxidation in pork loin during cold storage. This also implied that autoxidation of Mb in freezed and thaw pork loin was influenced by enzyme-catalysed reactions in the tissue that would lead to decreased OxyMb.