宰后成熟过程中活性氮与活性氧串扰对牦牛肉食用品质及微观结构的影响

Effects of reactive nitrogen species and reactive oxygen species crosstalk on edible quality and microstructure of yak meat during postmortem

为研究宰后成熟过程中活性氧(reactive oxygen species,ROS)与活性氮(reactive nitrogen species,RNS)串扰对牦牛肉食用品质及微观结构的影响。以经ROS促进剂、抑制剂与NO供体、一氧化氮合成酶抑制剂两两组合处理后的牦牛肉为研究对象,分析处理后成熟期间牦牛肉食用品质及微观结构的变化。结果显示,相比对照组,成熟期间同时激活ROS和RNS可显著增加牦牛肌肉的a^(*)值,而促进ROS的同时抑制RNS可显著降低L^(*)值和a^(*)值。同时,与对照组相比,激活ROS的同时促进或抑制RNS,牦牛肉pH值、剪切力、硬度和咀嚼性显著降低(P<0.05),而蒸煮损失、肌原纤维小片化指数(myofibrillar fragmentation index,MFI)和肌原纤维结构的断裂程度显著增加,利于肉的嫩化,这与抑制ROS的同时激活或抑制RNS对上述品质变化的影响相反。此外,高氧条件下,较RNS促进组相比,抑制RNS可显著降低牦牛肉的pH值、L^(*)值、a^(*)值、蒸煮损失、硬度、咀嚼性和剪切力值,而使MFI显著增大(P<0.05);低氧条件下,较RNS抑制组相比,激活RNS可显著增加牦牛肉pH值、a^(*)值、蒸煮损失和MFI,而使剪切力显著降低(P<0.05)。以上研究表明,抑制ROS条件下,激活或抑制RNS可阻碍肌肉的嫩化,而激活ROS的条件下激活或抑制RNS可有效改善牦牛肉的嫩度。综上,宰后ROS诱导蛋白氧化发生的同时抑制RNS可有效改善牦牛肉的嫩度。

This study aimed to investigate the effects of reactive oxygen species(ROS)and reactive nitrogen species(RNS)crosstalk on the edible quality and microstructure of yak meat during postmortem.Yak meat treated with two combinations of ROS promoter,ROS inhibitor,NO donor,and nitric oxide synthase inhibitor was used to analyze the changes in edible quality and microstructure of yak meat during postmortem.The results showed that both activation of ROS and reactive nitrogen species(RNS)significantly increased the a^(*)values of yak meat compared with the control group;whereas the L^(*)and a^(*)values were significantly decreased by activating ROS while inhibiting RNS,respectively.Meanwhile,activation of ROS along with activation or inhibition of RNS significantly decreased pH,shear,hardness and chewiness,while cooking loss,myofibrillar fragmentation index(MFI)and the degree of myofibrillar structural fracture significantly increased in yak meat compared to the control group(P<0.05),which favored meat tenderization.This is in contrast to the effect of inhibiting of ROS along with activation or inhibition of RNS on the above quality changes.In addition,under high oxygen conditions,inhibition of RNS significantly decreased the pH,L^(*),a^(*),cooking loss,hardness,chewiness and shear force of yak meat,while significantly increasing the MFI,compared to the RNS-promoted group;Under hypoxic conditions,activation of RNS significantly increased yak meat pH,a^(*)value,cooking loss,MFI,and significantly decreased shear force compared to RNS inhibition(P<0.05).The above studies showed that activation or inhibition of RNS under ROS-inhibited conditions hindered muscle tenderisation,whereas activation or inhibition of RNS under ROS-activated conditions effectively improved the tenderness of yak meat.In conclusion,post-slaughter ROS-induced protein oxidation occurred while inhibition of RNS could effectively improve the tenderness of yak meat.