低场NMR法研究微生物转谷氨酰酶对猪肉肌原纤维蛋白凝胶功能特性的影响

Effect of microbial transglutaminase on functionality of pork myofibrillar protein gel—a low field NMR method

用低场核磁共振(NMR)研究了微生物转谷氨酰酶(MTG)对猪肉肌原纤维蛋白凝胶质子核磁共振弛豫行为的影响。研究结果显示,NMR结果拟合后得到的水有4个组分,合并为对应水的3种状态即结合水、不易流动水和自由水。和对照相比,加酶处理后显著降低了猪肉肌原纤维蛋白热诱导凝胶的自旋-自旋弛豫时间(T2)。加入2 U.g-1剂量的MTG后,T22b值(对应于不易流动水)由226 m s(峰值)降低到188 m s。然而,当酶浓度增加时,T22b没有进一步降低。对衰减NMR信号拟合结果进行主成分分析显示,前两个主成分可以解释变异方差的80%,并且加酶和对照在样品评分图上显著分开。加入MTG后,凝胶中水质子的移动性显著下降。

The effect of microbial transglutaminase （MTG） on nuclear magnetic resonance （NMR） relaxation behaviour of pork myofibrillar protein （PMP） gel was studied by low field NMR method. The NMR data was fitted to four components, which were merged into three states of water, i. e. bound, immobile and free water. The enzymatic protein preparation had significantly lowered values of spin-spin relaxation time （ T2 ） in comparison with the control system. T22b （ immobile water） was reduced from 226 ms （peak value） of PMP gel containing no MTG to 188 ms of PMP gel containing 2 U · g-1 protein. However, no further decrease was shown when the concentration of MTG increased. The principal component analysis （PCA） of the fitted decay NMR signal indica- ted the first two principal components （ PC ） could explain 80% of total variance and the sample with MTG added were different from the one without MTG in the case score figure. And with MTG added, the mobility of water proton in PMP gel decreased.