Impact and control of mechanical stress on protein structures during formulation in premix-emulsification

该项目的目的是量化预混合膜乳化过程中机械应力（应力停留时间）和由此引起的蛋白质和生物团聚体结构变化。在此基础上，确定了蛋白质和生物团聚体应激反应的潜在机制，并推导了工艺设计和控制的概念。假设蛋白质的结构变化取决于应力在膜中的停留时间。在项目的第一部分中，从工艺和结构水平上研究了β-乳球蛋白在膜中的结构变化作为应力停留时间的函数。在接下来的项目中，将系统地研究蛋白质的分子间相互作用和过程环境内的相互作用以及膜上的吸附现象。蛋白质结构将通过使用结构修饰的β-乳球蛋白变体（高压修饰蛋白、淀粉样聚集体、重组蛋白）来改变。利用傅里叶变换红外光谱和圆二色性等高分辨率蛋白质分析技术研究了复合材料的性质。分析组合将通过渗透法和分析超离心得到扩展。模拟技术将通过分子动力学的扩展方法来完成。此外，在项目的第二部分，脂肪酶将作为具有复杂三级和四级结构的模型蛋白。将调查其活动的变化，从而产生有关生物系统中与过程有关的压力和功能丧失的知识。为了实现具体项目的目标，不来梅莱布尼茨研究所多相流系与柏林工业大学食品技术和食品材料科学系之间需要密切合作，利用他们在过程和结构层面的分析和建模能力。在分子间相互作用和吸附过程的表征方面的具体能力由柏林工业大学食品胶体系提供。在优先项目中与其他合作伙伴的密切合作将导致对过程诱导应力及其在各种不同情况下对生物系统材料特性的影响的广泛理解。这种理解将允许更有针对性的工艺工程和生物系统适应其特定的工艺环境。

The aim of the project is to quantify the mechanical stress (stress residence time) and resulting process-induced structural changes on proteins and bio-agglomerates during premix membrane emulsification. Based hereon underlying mechanisms of stress response for proteins and bio-agglomerates are identified and concepts for process design and control are derived. It is assumed that the structural change of proteins depends on the stress residence time in the membrane.In the first part of the project, structural changes of β-lactoglobulin in the membrane as a function of the stress residence time were investigated at the process and on the structural level. In the upcoming part of the project, the intermolecular interactions of proteins and interactions within the process environment as well as sorption phenomena at the membrane will be systematically investigated. Protein structures will be varied by using structurally modified variants of β-lactoglobulin (high-pressure-modified protein, amyloid-like aggregates, recombinant proteins). The complex material properties were studied using high-resolution protein analysis such as Fourier transform infrared spectroscopy and circular dichroism. The analytical portfolio will be extended by osmometry and analytical ultracentrifugation. Simulation techniques will be completed with an extended approach of molecular dynamics. Furthermore, in the second part of the project, the enzyme lipase will be used as a model protein with complex tertiary and quaternary structure. Change in its activity will be investigated and thus knowledge about process-related stress and loss of functionality in biological systems will be generated.To fulfill the aim of the specific project, a close cooperation between the Department of Multiphase Flow of the Leibniz Institute in Bremen and the Department of Food Technology and Food Material Science of the Technical University Berlin with their competencies in analysis and modeling at the process and the structural level is required. Specific competencies on the characterization of intermolecular interactions and sorption processes are provided by the Department of Food Colloids of the Technical University Berlin. Close cooperation with other partners within the priority program will lead to a generalized understanding of process-induced stress and its impact on material properties of biological systems in a wide range of different scenarios. This understanding will allow a more targeted process engineering and adaption of biological systems to their specific process environment.