熔球态β-乳球蛋白纳米颗粒的泡沫稳定作用机制：从分子尺度到宏观尺度

Currently, the foam prepared from food-grade nanoparticle is less stable comparing with foam prepared from hard colloidal inorganic nanoparticles. Therefore, development of novel food-grade nanoparticle that can be used to produce highly stable food foam, has always been a popular research topic in food related area. In this project, we propose β-lactoglobulin as the research objective, to produce protein nanoparticles by using microbial transglutaminase (mTG) to induce cross-linking between molten state β-lactoglobulin monomers, and to study the stabilization mechanism of produced protein nanoparticles on foam. Based on formation of covalent bonds, the nanoparticle prepared from this method has potential higher stability and density, which would have positive impact on developing highly stable food foam. The main studies to be carried out include: exploration of the effect of protein secondary and tertiary structures and the distribution of substrate amino acids on mTG induced cross-linking from molecular scale, by using method that in combination of protein structural analysis technique and computational molecular dynamic simulation; investigation of the effect of structural and physiochemical properties of protein nanoparticle on foam stability, by characterization of β-lactoglobulin nanoparticles. The purpose of this study is to explore the relationship between protein molecular conformation, mesoscale characteristics of protein nanoparticles and the macroscopic properties of foam, to provide theoretical basis for foam stability mechanism for enzymatic cross-linking protein nanoparticle, and to point out a potential pathway for application of protein nanoparticles in food related area.

目前，食品级纳米颗粒的泡沫稳定作用与硬胶体无机纳米颗粒相比仍有相当差距，探究可用于制备高稳定性食品泡沫的新型纳米颗粒一直是食品领域的热点研究问题。本项目以β-乳球蛋白为研究对象，采用微生物谷氨酰胺转氨酶（mTG）诱导交联熔融态β-乳球蛋白方法，制备蛋白质纳米颗粒，研究其对泡沫的稳定作用机制。这种蛋白质纳米颗粒基于蛋白质之间的共价键形成，具有潜在高稳定性和致密性，对制备高稳定性食品泡沫具有积极影响。拟展开的主要研究有：结合蛋白结构解析技术和计算机分子动态模拟，从分子层面探明蛋白质结构及底物氨基酸分布对mTG酶交联的影响；对β-乳球蛋白纳米颗粒进行表征，研究其结构特征和理化特性对泡沫稳定性所起的作用。本课题旨在探明蛋白质分子构象、蛋白质纳米颗粒中尺度特征和泡沫的宏观特性的相互关系，为酶交联蛋白质纳米颗粒的泡沫稳定作用机制提供理论依据，对促进蛋白质纳米颗粒在食品领域的应用提供一条新途径。

泡沫是常见的食品类型，在泡沫类型食品的加工和储存过程中，容易出现脱水收缩的不稳定现象，因此如何提高食品泡沫体系的稳定性，一直是食品领域的热点研究问题。本项目以常见球蛋白为研究对象，采用微生物谷氨酰胺转氨酶（mTG）诱导交联熔融态蛋白质方法，制备蛋白质纳米颗粒，用于稳定泡沫体系。本项目结合蛋白结构解析技术和计算机分子动态模拟，从分子层面解析了蛋白质结构及底物氨基酸分布对mTG酶交联的影响；基于β-乳球蛋白和大豆蛋白制备了两种蛋白质纳米颗粒，对蛋白纳米颗粒进行表征，研究了蛋白质分子构象、蛋白质纳米颗粒中尺度特征和泡沫的宏观特性的相互关系，为酶交联蛋白质纳米颗粒的泡沫稳定作用机制提供理论依据，对促进蛋白质纳米颗粒在食品领域的应用提供一条新途径。