pH条件对肌原纤维蛋白乳液微凝胶性质的影响

Properties of Myofibrillar Protein Emulsion Microgels: Effect of pH

摘要:

肌原纤维蛋白乳液微凝胶是在加热肌原纤维蛋白乳状液过程中同时施加剪切，导致变性蛋白质聚集在乳状液滴上所形成的离散球形颗粒。通过测定不同pH条件下制备的肌原纤维蛋白乳液微凝胶流变行为及微观结构，研究pH对其流变性质的影响。结果表明：在强酸性条件及接近其等电点时，乳液微凝胶的粒径大于其他pH范围。不同pH条件下的乳液微凝胶均为非牛顿流体，具有假塑性流体特征，pH的变化不会改变其流体类型。其黏度随pH的升高呈现先减小后增大的趋势，pH为6时，在低频率扫描时呈现最高的黏弹性，触变性也最好。剪切恢复力测试中，微凝胶颗粒的结构受到一定程度的破坏，其中pH为5时恢复性最好。

Abstract:

Myofibrillar protein emulsion microgels is a kind of discrete spherical particles formed by the aggregation of denatured proteins on the emulsion droplets when the myofibrillar protein emulsion is heated and sheared at the same time. In this investigation, the effects of pH on the rheological properties of myofibrillar protein emulsion microgels were studied by measuring the rheological behavior and microstructure of microgels prepared under different pH conditions. Results showed that the particle size of myofibrillar emulsion microgels under strong acid condition and near its isoelectric point was significantly larger than that of other pH ranges. The emulsion microgels under different pH were all non-Newtonian fluids with the pseudoplastic fluid characteristics, and pH condition would not change the fluid type of emulsion microgels. The viscosity first decreased and then increased with the increase of pH value. At pH 6, myofibrillar emulsion microgels showed the highest viscoelasticity at low frequency sweep with the optimum thixotropy. In the shear resilience test, the structure of microgel particles was damaged to a certain extent, while the optimal recovery was achieved at pH 5.