低场NMR研究pH对肌原纤维蛋白热诱导凝胶的影响0平面轴承

低场NMR研究pH对肌原纤维蛋白热诱导凝胶的影响

低场NMR研究pH对肌原纤维蛋白热诱导凝胶的影响 2011年12月04日 来源： 低场NMR研究pH对肌原纤维蛋白热诱导凝胶的影响

韩敏义1，2，费英1，徐幸莲1，周光宏1（1南京农业大学农业部农畜产品加工与质量控制重点开放实验室，南京 210095； 2河北科技大学生物科学与工程学院，石家庄 050018） 摘要：【目的】pH对猪肉肌原纤维蛋白热诱导凝胶保水性及水的移动性质影响；【方法】从猪肉中提取了肌原纤维蛋白，用低场NMR（nuclear magnetic resonance, NMR）研究了pH对肌原纤维蛋白热诱导凝胶中水的T2驰豫性质的影响。同时用离心法测量了pH对肌原纤维蛋白凝胶保水性（water holding capacity, WHC）影响；【结果】NMR结果拟合后得到水有四个组分，合并为对应水的三种状态即不可移动水pH的升高，pH偏离肌原纤维蛋白的等电点（pI），代表可移动水的T2驰豫时间显著增加，其所占峰的面积和凝胶的WHC也随之增加；主成分分析结果发现，处理等电点附近的样品在样品评分图上与其他pH样品显著不同；【结论】凝胶保水性的增加主要是可移动水的增加，凝胶WHC增加的原因可能是肌原纤维凝胶后孔径的增加，从而可以容纳更多的水。关键词：猪肉肌原纤维蛋白凝胶；保水性（WHC）；驰豫；pH值Heat-induced gelation of myofibrillar proteins as affected by pH-A low field NMR study HAN Min-yi1，2, Fei Ying1, XU Xing-lian1, ZHOU Guang-hong1（1Key Lab of Meat Processing and Quality Control, Ministry of Education, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095; 2College of Bioscience and Bioengineering, Hebei University of Science and Technology, Shijiazhuang, 050018）Abstract：【OBJECTIVE】The objective of this study is to discuss the effect of pH on the water holding capacity (WHC)and water mobility of pork myofibrillar protein heat-induced gelation;【METHOD】Myofibrillar proteins were extracted from porcine muscle, and their heat-induced gelation water properties were characterized using low-field nuclear magnetic resonance (NMR) T2 relaxometry. The water holding capacity (WHC) of the system was determined by centrifugation method; 【RESULT】The NMR data was fitted to four components, which were merge to three states of water, i.e. immobile, mobile and free water; T2 relaxation time, peak area, and WHC which attribute to mobile water increased as pH away from pI, the principal components analysis result showed the sample near pI clustered differently from others;【CONCLUSION】The improvement of WHC could be ascribed to the increasing of the mobile water, and the possible increase of the myofibrilar protein gel network pore diameter may leads to more water could be entrapped. Key words: Pork myofibrillar protein gel; WHC; relaxation; pH

郑州市第二按摩医院

殷霞

昆明甲亢医院

虚炎

广西中医药学院