Real effect of pH on CIE L*, a* and b* of loins during 24 h chilling of beef carcasses

Twenty six mate Hanwoo (Korean cattle) carcasses were measured for pH, temperature and instrumental color changes of loins during 24 h post-mortem carcass chilling at 4 degreesC in the cooler. The average internal temperature of loins was about 5 degreesC after 24 h of chilling, and with the exclusion of those with an ultimate pH >6.0 (dark-cutters), the average pH value was 5.5. When all carcasses were considered for the partial correlation coefficient between color and pH, with the temperature effect excluded, CIE L*, a* and b* seemed to be affected significantly by pH during chilling process (p <0.001). However, when carcasses with dark-cutting condition were excluded, the correlation coefficients were much lower. In contrast, when the partial correlation coefficients between color and temperature, excluding the effect of pH on them, were analyzed, the relationship between color and temperature did not change much after values of DFD (dark, firm, dry) beef were excluded. The results suggested that the known interrelationship of color and pH in chilled beef loins be mainly due to the influence of temperature on pH and color.