Abstract A buttermilk that is rich in functional components from milk fat globule membrane (MFGM) is of great interest to industry and consumers. However, isolation of such components is challenging because of the complexes they form with proteins. In this contribution, we describe a process, the ideal butter process, for separating milk fat globules and proteins in cream prior butter making to enhance MFGM deployment. First, raw and pasteurized bovine creams were micro-diafiltered with water using a tubular ceramic membrane. A 1.4 µm pore size was selected for the membrane to separate proteins and fat globules. Two trans-membrane pressures (0.4 and 0.6 bar) were used to determine the permeate flux and protein mass flow needed in the evaluation of the filtration efficiency. Compared to pasteurized cream, raw cream led to shorter filtration time. Pasteurization induced protein adsorption on the surface of fat globules, thus decreasing separation efficiency. Furthermore, pH was found to fluctuate during the diafiltration, owing to the decrease of buffering capacity by cream in the course of protein and mineral permeation and subsequent equilibration process of colloidal phosphates with serum phase. A relatively higher filtration pH increased filtration efficiency and protected fat globules from coalescence, given the increased osmotic pressure (electrostatic repulsion). Overall, the protein content in cream decreased by ~ 80% upon microfiltration. Despite the reduced protein concentration in the filtered creams, no negative effects were observed during churning into butter, which resulted in low-protein content buttermilk (~ 80% protein reduction). Hence, the ideal butter process can be used to facilitate MFGM isolation and better handling of process streams.

中文翻译：

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热处理和 pH 值对微渗滤效率的影响，用于在黄油生产中从奶油中分离天然脂肪球

摘要 一种富含乳脂肪球膜（MFGM）功能成分的酪乳引起了业界和消费者的极大兴趣。然而，由于它们与蛋白质形成复合物，因此这些成分的分离具有挑战性。在这篇文章中，我们描述了一种工艺，即理想的黄油工艺，用于在制作黄油之前分离奶油中的乳脂肪球和蛋白质，以增强 MFGM 的部署。首先，使用管状陶瓷膜用水对生的和巴氏杀菌的牛乳膏进行微渗滤。选择 1.4 µm 孔径的膜来分离蛋白质和脂肪球。使用两个跨膜压力（0.4 和 0.6 巴）来确定评估过滤效率所需的渗透通量和蛋白质质量流量。与巴氏杀菌奶油相比，生奶油的过滤时间更短。巴氏杀菌导致脂肪球表面吸附蛋白质，从而降低分离效率。此外，由于在蛋白质和矿物质渗透过程中以及随后的胶体磷酸盐与血清相的平衡过程中，乳膏的缓冲能力降低，因此在渗滤过程中发现 pH 值波动。考虑到渗透压（静电排斥）的增加，相对较高的过滤 pH 值会提高过滤效率并防止脂肪球聚结。总体而言，微滤后奶油中的蛋白质含量降低了约 80%。尽管过滤后的奶油中蛋白质浓度降低，但在搅拌成黄油的过程中没有观察到负面影响，这导致酪乳蛋白质含量低（蛋白质减少约 80%）。因此，