宰后成熟时间对不同年龄牦牛肉用品质的影响

研究宰后成熟时间对不同年龄牦牛肉用品质（pH值、肉色、肌红蛋白含量、剪切力、失水率、蒸煮损失率）的影响，并分析成熟时间、年龄与肉用品质之间的相关性。结果表明：宰后成熟过程中，不同年龄牦牛肉L*值和b*值随着成熟时间的延长先上升后下降，而a*值先下降后上升；肌红蛋白含量随着成熟时间的延长而降低；pH值在成熟的前3 d发生了显著的变化（P＜0.05），成熟过程中不同年龄牦牛肉pH值没有显著差异（P＞0.05）；失水率和蒸煮损失率在宰后成熟的第3天时达到最大；成熟3 d后，剪切力值显著降低（P＜0.05）；年龄与牦牛肉用品质指标均呈正相关，而成熟时间与L*值、b*值、失水率、蒸煮损失率呈较强的正相关，与剪切力、肌红蛋白含量呈显著负相关（P＜0.05）；牦牛宰后经过7 d的成熟，可以降低因屠宰年龄不同而产生的差异，同时也可以改善肉的嫩度。

Influence of Postmortem Aging Time on Meat Quality of Yaks at Different Ages

This study investigated the effects of postmortem aging time on meat quality of yaks at different ages as indicated
by the changes in pH, meat color, total myoglobin (TMb) content share force, water loss rate and cooking loss and analyzed
the correlations between meat quality and postmortem aging time or slaughter age. The results showed that the L* and b*
values of yak meat at different slaughter ages initially rose and then decreased with postmortem aging, while a* values
showed the contrary trend. The content of TMb decreased with postmortem aging, and the pH was significantly changed
(P < 0.05) in the first three days during the period of aging although not significantly affected by different slaughter (P > 0.05).
The water loss rate and cooking loss reached the maximum on the third day of aging. Share force significantly declined
(P < 0.05) after three days of aging. There was a positive correlation between slaughter age and the quality indexes of yak
meat as well as highly positive correlations of postmortem aging time with L* values , b* values, water loss rate and cooking
loss, whereas the correlations with share force and TMb contents were significantly negative (P < 0.05). After seven days of
postmortem aging, the differences in yak meat at different slaughter ages were less apparent and the tenderness of meat was
improved at the same time.