The objectives of this study were to investigate 1) the relationship between color and water-holding capacity (WHC) in the longissimus thoracis et lumborum of pork, 2) the influences of rate of glycolysis, decline rate of carcass temperature, carcass weight, sex, content of intramuscular fat and moi...
The objectives of this study were to investigate 1) the relationship between color and water-holding capacity (WHC) in the longissimus thoracis et lumborum of pork, 2) the influences of rate of glycolysis, decline rate of carcass temperature, carcass weight, sex, content of intramuscular fat and moisture on meat color and WHC, and 3) the pork quality characteristics of PSE (pale, soft, exudative) and DFD (dark, firm, dry) in relation with composition of muscle fiber types. For these purposes, five experiments were designed with four hundred nineteen pigs (Landrace×Korean native black pig) that had fed in Livestock Research Center at Jeju island in Korea. All pigs were slaughtered at a commercial slaughter house, and muscle samples at 1hr postmortem and loin cuts at 24hr postmortem were collected to measure color, WHC, pH, sarcomere length, shear force, protein solubility and composition of muscle fiber types. The relationship between color and WHC was carefully investigated in Experiment 1. Color was significantly correlated with WHC, and it was proposed that the variation of WHC could be explained by the variation of color measurements. CIE L*, C*, h color space showed better relation to the subjective color score than L*, a*, b* color space and the lightness (L*) was the best to predict WHC. When only L* was used to predict drip loss % of pork loin the proportion of correct was 27% which was very low. Therefore it was suggested that multi-regression equation including hue and yellowness would be better to predict more correct drip loss %. Also pHu showed the negative correlation with lightness and drip loss significantly, but the proportion of correct for lightness and drip loss by pHu were 44% and 17%, respectively. These data implied that it might be unsuitable to predict pork quality by pHu only. Data also suggested that pork quality should not be evaluated by only lightness, drip loss or pHu. The influences of rate of glycolysis and decline rate of carcass temperature, carcass weight and sex, content of intramuscular fat and moisture on meat color and WHC were investigated in Experiments 2, 3, and 4, respectively. In experiment 2, pH1 affected on ultimate pork quality, so L*, drip loss and Filter paper fluid were significantly increased with decreasing of pH (p<0.05). pHu had significant correlation with moisture content (p<0.01), but there was no significant correlation between crude fat content and pHu. Results suggested that WHC of pork loin could be affected by rapid decline of muscle pH postmortem, resulted in increased lightness due to exudative moisture on the surface of pork. Data in experiment 3 showed no significant correlation between carcass weight and color and WHC. However moisture content was significantly higher in very light group, and very heavy group showed significantly higher pH at 1, 3 and 6 h postmortem (p<0.05). No influence of carcass weight on carcass temperature was observed in this experiment. Results showed that shear force was increased with decreasing of sarcomere length. Color measurements were significantly affected by sex, and L* of female was significantly higher than that of male, but female showed higher a* values. Also FPF of female was significantly higher compared to male. Results implied that pork quality factors, i.e. color and WHC etc., would be affected by carcass weight and sex. Results in experiment 4 showed that content of intramuscular fat and moisture significantly affected on color and WHC of pork. Although there was no significant increase in L*, chroma and hue values were increased with increasing of intramuscular fat content (p<0.05). Data showed that content of intramuscular fat was lower with higher content of moisture. Drip loss % and FPF were increased with increased moisture content, and higher pH at 3, 6 and 24h postmortem were observed in higher moisture group. Sarcomere length was shorter in higher content of moisture, resulted in higher shear force value (p<0.05). Data showed obviously increasing moisture content concomitantly reduced intramuscular fat. Results suggested that color and WHC of pork might be influenced by contents of intramuscular fat and moisture. The characteristics of PSE and DFD were investigated in experiment 5. Both PSE and DFD samples showed significantly lower crude fat content, and sarcoplasmic protein content was lowest in PSE samples. Sarcomere length was significantly longer than DFD and normal pork (p<0.05). PSE samples had significantly lower in muscle fiber type IIb and larger in diameter of muscle fibers. However DFD samples had higher in muscle fiber type IIb and smaller in diameter of muscle fibers. Moreover PSE pork had longer sarcomere length compare to DFD and normal prok. Diameter (um) of muscle fiber type Ⅰ and Ⅱb were significantly longer in PSE pork (p<0.05). Data suggested that pork quality would be affected by composition of muscle fiber types in porcine muscles.
The objectives of this study were to investigate 1) the relationship between color and water-holding capacity (WHC) in the longissimus thoracis et lumborum of pork, 2) the influences of rate of glycolysis, decline rate of carcass temperature, carcass weight, sex, content of intramuscular fat and moisture on meat color and WHC, and 3) the pork quality characteristics of PSE (pale, soft, exudative) and DFD (dark, firm, dry) in relation with composition of muscle fiber types. For these purposes, five experiments were designed with four hundred nineteen pigs (Landrace×Korean native black pig) that had fed in Livestock Research Center at Jeju island in Korea. All pigs were slaughtered at a commercial slaughter house, and muscle samples at 1hr postmortem and loin cuts at 24hr postmortem were collected to measure color, WHC, pH, sarcomere length, shear force, protein solubility and composition of muscle fiber types. The relationship between color and WHC was carefully investigated in Experiment 1. Color was significantly correlated with WHC, and it was proposed that the variation of WHC could be explained by the variation of color measurements. CIE L*, C*, h color space showed better relation to the subjective color score than L*, a*, b* color space and the lightness (L*) was the best to predict WHC. When only L* was used to predict drip loss % of pork loin the proportion of correct was 27% which was very low. Therefore it was suggested that multi-regression equation including hue and yellowness would be better to predict more correct drip loss %. Also pHu showed the negative correlation with lightness and drip loss significantly, but the proportion of correct for lightness and drip loss by pHu were 44% and 17%, respectively. These data implied that it might be unsuitable to predict pork quality by pHu only. Data also suggested that pork quality should not be evaluated by only lightness, drip loss or pHu. The influences of rate of glycolysis and decline rate of carcass temperature, carcass weight and sex, content of intramuscular fat and moisture on meat color and WHC were investigated in Experiments 2, 3, and 4, respectively. In experiment 2, pH1 affected on ultimate pork quality, so L*, drip loss and Filter paper fluid were significantly increased with decreasing of pH (p<0.05). pHu had significant correlation with moisture content (p<0.01), but there was no significant correlation between crude fat content and pHu. Results suggested that WHC of pork loin could be affected by rapid decline of muscle pH postmortem, resulted in increased lightness due to exudative moisture on the surface of pork. Data in experiment 3 showed no significant correlation between carcass weight and color and WHC. However moisture content was significantly higher in very light group, and very heavy group showed significantly higher pH at 1, 3 and 6 h postmortem (p<0.05). No influence of carcass weight on carcass temperature was observed in this experiment. Results showed that shear force was increased with decreasing of sarcomere length. Color measurements were significantly affected by sex, and L* of female was significantly higher than that of male, but female showed higher a* values. Also FPF of female was significantly higher compared to male. Results implied that pork quality factors, i.e. color and WHC etc., would be affected by carcass weight and sex. Results in experiment 4 showed that content of intramuscular fat and moisture significantly affected on color and WHC of pork. Although there was no significant increase in L*, chroma and hue values were increased with increasing of intramuscular fat content (p<0.05). Data showed that content of intramuscular fat was lower with higher content of moisture. Drip loss % and FPF were increased with increased moisture content, and higher pH at 3, 6 and 24h postmortem were observed in higher moisture group. Sarcomere length was shorter in higher content of moisture, resulted in higher shear force value (p<0.05). Data showed obviously increasing moisture content concomitantly reduced intramuscular fat. Results suggested that color and WHC of pork might be influenced by contents of intramuscular fat and moisture. The characteristics of PSE and DFD were investigated in experiment 5. Both PSE and DFD samples showed significantly lower crude fat content, and sarcoplasmic protein content was lowest in PSE samples. Sarcomere length was significantly longer than DFD and normal pork (p<0.05). PSE samples had significantly lower in muscle fiber type IIb and larger in diameter of muscle fibers. However DFD samples had higher in muscle fiber type IIb and smaller in diameter of muscle fibers. Moreover PSE pork had longer sarcomere length compare to DFD and normal prok. Diameter (um) of muscle fiber type Ⅰ and Ⅱb were significantly longer in PSE pork (p<0.05). Data suggested that pork quality would be affected by composition of muscle fiber types in porcine muscles.
주제어
#Meat color Water-holding capacity Pork 돈육 보수력 육색
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