In this study, carbon monoxide (CO) modified atmosphere packaging (MAP) was used to increase redness (a*) and lightness (L*) values of dark cutting beef (ultimate pH (pHu) ≥ 6.10), compared to normal pHu beef and intermediate pHu beef (pH: 5.40–5.79; pH: 5.80–6.09, respectively) during 20 d chilled storage. Compared with HiOx-MAP, CO-MAP exhibited similar color improvement effects (increased L*, a*, b* values) for all pHu beef groupings. The metmyoglobin (MetMb) content was lower under CO-MAP than that of HiOx-MAP in normal pHu beef, but opposite effects were observed in dark, high pH beef. This result could not be explained by MetMb reducing ability (MRA) and lipid oxidation, as both parameters were higher in CO-MAP beef than either normal or high pHu beef, compared with HiOx-MAP. In conclusion, CO-MAP was effective to maintain the cherry red color for dark cutting beef, but the color improvement mechanisms might be different with HiOx packaging methods.

在这项研究中，与普通pHu牛肉相比，一氧化碳（CO）气调包装（MAP）用于增加暗切牛肉的红色（a *）和亮度（L *）值（最终pH（pHu）≥6.10）。冷藏期间20 d的中级pHu牛肉（pH：5.40-5.79； pH：5.80-6.09）。与HiOx-MAP相比，CO-MAP表现出相似的色彩改善效果（L *，a *，b增加*值）适用于所有pHu牛肉分组。在普通pHu牛肉中，CO-MAP下的肌红蛋白（MetMb）含量低于HiOx-MAP，但在深色，高pH值的牛肉中却观察到相反的效果。MetMb还原能力（MRA）和脂质氧化无法解释该结果，因为与HiOx-MAP相比，CO-MAP牛肉中的两个参数均高于正常或高pHu牛肉。总之，CO-MAP可以有效地保持深色切牛肉的樱桃红色，但是颜色的改进机制可能与HiOx包装方法不同。