Rodríguez Patino Juan M, Cejudo Fernández Marta, Rodríguez Niño M Rosario, Carrera Sánchez Cecilio
Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, C/. Prof. García González 1, 41012 Seville, Spain.
J Agric Food Chem. 2006 May 17;54(10):3723-32. doi: 10.1021/jf053142r.
The effect of monoglycerides (monopalmitin and monoolein) on the structural, topographical, and dilatational characteristics of betacasein adsorbed film at the air-water interface has been analyzed by means of surface pressure (pi)-area (A) isotherms, Brewster angle microscopy (BAM), and surface dilatational rheology. The static and dynamic characteristics of the mixed films depend on the interfacial composition and the surface pressure. At surface pressures lower than that for the beta-casein collapse (at the equilibrium surface pressure of the protein, pi(e)(beta-casein)) a mixed film of beta-casein and monoglyceride may exist. At higher surface pressures the collapsed beta-casein is partially displaced from the interface by monoglycerides. However, beta-casein displacement by monoglycerides is not quantitative at the monoglyceride concentrations studied in this work. The protein displacement by a monoglyceride is higher for monopalmitin than for monoolein and for spread than for adsorbed films. The viscoelastic characteristics of the mixed films were dominated by the presence of beta-casein in the mixture. Even at the higher surface pressures (at pi > pi(e)(beta-casein)) the small amounts of beta-casein collapsed residues at the interface have a significant effect on the surface dilatational properties of the mixed films. The structural, topographical, and viscoelastic characteristics of the mixed films corroborate the fact that protein displacement for monoglycerides is higher for spread than for adsorbed mixed films.
通过表面压力（π）-面积（A）等温线、布儒斯特角显微镜（BAM）和表面扩张流变学，分析了甘油单酯（单棕榈酸甘油酯和单油酸甘油酯）对β-酪蛋白在气-水界面吸附膜的结构、形貌和扩张特性的影响。混合膜的静态和动态特性取决于界面组成和表面压力。在低于β-酪蛋白塌陷的表面压力下（在蛋白质的平衡表面压力π(e)(β-酪蛋白)时），可能存在β-酪蛋白和甘油单酯的混合膜。在较高的表面压力下，塌陷的β-酪蛋白会被甘油单酯部分地从界面上取代。然而，在本工作研究的甘油单酯浓度下，甘油单酯对β-酪蛋白的取代并非定量的。单棕榈酸甘油酯对蛋白质的取代作用比对单油酸甘油酯的大，铺展膜比吸附膜的大。混合膜的粘弹性特性主要由混合物中β-酪蛋白的存在决定。即使在较高的表面压力下（π>π(e)(β-酪蛋白)），界面上少量的β-酪蛋白塌陷残余物对混合膜的表面扩张特性也有显著影响。混合膜的结构、形貌和粘弹性特性证实了这样一个事实，即甘油单酯对蛋白质的取代作用在铺展混合膜中比在吸附混合膜中更大。
