Pomastowski P, Sprynskyy M, Buszewski B
Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Interdisciplinary Centre of Modern Technologies, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun, Poland.
Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Interdisciplinary Centre of Modern Technologies, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun, Poland.
Colloids Surf B Biointerfaces. 2014 Aug 1;120:21-7. doi: 10.1016/j.colsurfb.2014.03.009. Epub 2014 May 21.
The presented research was focused on physicochemical study of casein properties and the kinetics of zinc ions binding to the protein. Moreover, a fast and simple method of casein extraction from cow's milk has been proposed. Casein isoforms, zeta potential (ζ) and particle size of the separated caseins were characterized with the use of capillary electrophoresis, zeta potential analysis and field flow fractionation (FFF) technique, respectively. The kinetics of the metal-binding process was investigated in batch adsorption experiments. Intraparticle diffusion model, first-order and zero-order kinetic models were applied to test the kinetic experimental data. Analysis of changes in infrared bands registered for casein before and after zinc binding was also performed. The obtained results showed that the kinetic process of zinc binding to casein is not homogeneous but is expressed with an initial rapid stage with about 70% of zinc ions immobilized by casein and with a much slower second step. Maximum amount of bound zinc in the experimental conditions was 30.04mgZn/g casein.
本研究聚焦于酪蛋白性质的物理化学研究以及锌离子与该蛋白质结合的动力学。此外，还提出了一种从牛奶中快速简便提取酪蛋白的方法。分别使用毛细管电泳、ζ电位分析和场流分级（FFF）技术对酪蛋白异构体、分离出的酪蛋白的ζ电位和粒径进行了表征。在批量吸附实验中研究了金属结合过程的动力学。应用颗粒内扩散模型、一级和零级动力学模型来测试动力学实验数据。还对锌结合前后酪蛋白的红外波段变化进行了分析。所得结果表明，锌与酪蛋白的结合动力学过程并非均匀一致，而是表现为一个初始快速阶段，约70%的锌离子被酪蛋白固定，以及一个慢得多的第二步。在实验条件下，锌的最大结合量为30.04mg Zn/g酪蛋白。
