介质阻挡放电低温等离子体处理对宰后羊肉嫩度的影响

Effect of Dielectric Barrier Discharge Low Temperature Plasma Treatment on Mutton Tenderness during Postmortem Stora

以宰后羊双侧背最长肌为研究对象,在宰后不同贮藏时间利用介质阻挡放电(dielectric barrier discharge,DBD)低温等离子体进行处理,通过分析贮藏期间样品pH值、菌落总数、肌原纤维小片化指数(myofibrillar fragmentation index,MFI)以及肌原纤维超微结构,明确在宰后不同时间进行DBD低温等离子体处理对羊肉嫩度的影响。结果表明:在贮藏过程中,宰后6h和12h进行DBD低温等离子体处理的羊肉贮藏至12h时pH值均显著低于其他处理组(P<0.05);宰后12~72h时用DBD低温等离子体处理样品的菌落总数较未处理组显著降低;随着贮藏时间的延长,各处理组MFI逐渐增大,且在6~72h内呈显著上升趋势(P<0.05),在72h后趋于稳定;宰后6~24h进行DBD低温等离子体处理样品的MFI增长速率总体显著高于其他样品组(P<0.05);宰后成熟早期(6~24h)DBD低温等离子体处理组肌节长度在贮藏24h时显著变短(P<0.05),且低于其他组别,且24h处理组在贮藏24h时肌节长度最短。综上,宰后12~24h时使用DBD低温等离子体处理羊肉在减菌的同时对其嫩度的影响效果最小。

The Longissimus dorsi muscle of sheep was treated at different times postmortem with dielectric barrier discharge(DBD)low temperature plasma and evaluated for pH,total number of bacteria,myofibrillar fragmentation index(MFI)and myofibril ultrastructure during postmortem storage.Our aim was to determine the effects of DBD low temperature plasma treatment at different times after slaughter on mutton tenderness.The results showed that after 12 h of postmortem storage,the pH of mutton treated with DBD low-temperature plasma at 6 and 12 h postmortem was significantly lower than that of the other treated groups(P<0.05);the total number of bacteria in mutton treated at 12–72 h after slaughter decreased significantly compared with the untreated group.As the storage time increased,MFI gradually increased,showed a significant upward trend during 6–72 h(P<0.05),and then tended to be stable after 72 h for all treated groups.DBD low temperature plasma treatment at 6–24 h postmortem significantly increased the growth rate of MFI than the other treatments(P<0.05).After 24 h storage,the sarcomere length of mutton treated at the early postmortem stage(6–24 h)was significantly reduced and shorter than that of the other treated groups(P<0.05),and the sarcomere length of mutton in the 24 h postmortem treatment group was the shortest.In conclusion,DBD low-temperature plasma treatment at 12 to 24 h postmortem had the least effect on the tenderness of mutton while reducing the number of bacteria.