Function of parvalbumin from fish muscle in adsorption on the oil-water interface during emulsification.

以鱼肉肌浆蛋白(SP)和细蛋白(PA)为乳化剂，在pH值为7.0的条件下，用分散剂或超声乳化器将蛋白质与三油酸乳化，考察了蛋白质在油水界面的吸附行为以及PA对乳状液的稳定作用。激光衍射法、显微镜和浊度法三种评价乳状液稳定性的方法对PA乳状液的稳定性评价趋势基本一致，而SP乳状液由于存在絮凝作用，不同方法的乳化值有所不同，PA乳状液具有较好的粒径分布，且乳状液颗粒较小。乳状液在中性pH条件下的不稳定主要是由乳状液引起的，不伴有絮凝和聚结。乳状液的絮凝和乳状化分别与分子电荷和蛋白质的吸附量密切相关。在乳化过程中，没有观察到PA在油水界面上的优势吸附，对于PA乳液而言，吸附在乳液颗粒上的带负电荷的分子的静电斥力可以提高乳液的稳定性。相反，由于乳液颗粒的比重较小，PA的薄膜应该成为乳化液更快乳化的一个因素，因此，微分散可以参与乳液的稳定。

Aqueous solution of sarcoplasmic proteins (SP) and parvalbumin (PA) from carp muscle were emulsified with triolein at pH 7.0 using a disperser or a sonicator and the adsorption behavior of the proteins on the oil-water interface and the function of PA in stabilization of the emulsion were investigated.Three kinds of evaluation methods (laser diffractometry, microscopy and turbidimetry) for stability of emulsion particles showed almost identical tendency for PA-emulsions, while the values for SP-emulsion were somewhat discrepant among those methods because of the flocculation.PA-emulsion had a superior size distribution with smaller particles. Instability of the emulsions at neutral pH was mainly induced with creaming, not accompanied by flocculation nor coalescence. Flocculation and creaming of emulsion were closely associated with molecular charge and amount of adsorbed proteins, respectively. Predominant adsorption of PA among SP components on the oil-water interface was not observed during emulsification.For PA-emulsions the electrostatic repulsion by the negatively charged molecules thinly adsorbed on the emulsion particles should increase the emulsion stability. In contrast such a thin membrane of PA should become to be a factor of the faster creaming for the smaller specific gravity of the emulsion particles and, consequently, microdispersion could be involved in the emulsion stabilization.