大豆油/水界面上大豆11S球蛋白吸附膜的膨胀流变特性

DILATATIONAL RHEOLOGICAL PROPERTIES OF SOY 11S GLOBULIN ABSORBED FILMS AT SOY OIL/WATER INTERFACE

本文采用轴对称滴形分析法(ADSA)检测了pH2.0和5.0条件下,大豆油/水界面上不同浓度(0.1-0.001%,w/w)的大豆11S球蛋白吸附膜的膨胀流变特征参数(膨胀模量、膨胀弹性、膨胀粘性及相角)随吸附时间的变化。实验表明,在温度(23℃)和体相溶液离子强度(0.05)恒定的条件下,随着吸附时间的延长,表面膨胀模量增大,相角减小。膨胀弹性明显大于膨胀粘性,因此,从表面流变学的角度分析,油/水界面上粘弹性的大豆11S球蛋白吸附膜实际上是弹性的。膨胀模量随液滴体相蛋白浓度的增加而增大,受体相pH值的影响很大。pH2.0时,吸附膜的膨胀模量明显大于pH5.0时吸附膜的膨胀模量。

Surface cous components, dilatational rheological parameters （surface dilatational modulus, its elastic and visand phase angle） of soy 11S globulin films adsorbed at soy oil/water interface were measured as a function of adsorption time by axisymmetric drop shape analysis method （ADSA）. The experiments were performed at various concentration （from 0.1 to 0.001%, w/w） and pH （2.0 and 5.0）. The temperature and ionic strength were maintained at 23℃ and 0.05 M respectively. The results indicated that surface dilatational modulus increase, and the phase angle decreases with absorption time. Soy 11S globulin films adsorbed at oil/water interface exhibit larger dilatational elasticity than dilatational viscosity and thus are practically elastic from a surface rheological point of view. Dilatational modulus increases with the protein concentration in the drop bulk phase, especially depending on drop bulk pH. At pH 2.0, dilatational modulus of adsorption films are markedly higher than at pH 5.0.