Purification of milk peptides using integrated membrane processes

牛乳蛋白是目前公认的具有抗高血压、免疫调节、脂类和矿物质结合以及抗菌等生物活性的多肽的来源。 这些所谓的生物活性肽越来越多地用作食品系统中的健康成分或补充剂。生物活性肽的特征在于不同的电荷（阳离子、阴离子、中性）和分子量值（500-2000 Da），可以通过酶水解产生。 与生物活性肽的生产相关的主要问题是找到一种从复杂混合物中纯化它们的方法，以提高它们的效力。目前的工作是基于这样的假设，即基于膜的过程集成的大小，电荷和溶解度作为分离参数可以成功地实现从复杂的混合物中的肽的纯化（>95%）。 本工作的目的是开发一种基于膜的牛奶中阳离子、阴离子和中性肽的纯化方法。该项目的目标是：（1）评价市售的不同NF膜材料用于从复杂混合物中分离酸性肽的潜力;（2）表征聚电解质存在的影响（多糖）对b-LG肽混合物和NF级分中的溶解度、二级结构和肽-肽相互作用的影响;（3）表征b-LG肽对NF分离选择性的结合特征;（4）将NF和预处理与复杂系统（如完全乳或乳清蛋白水解物）相结合的分离方法。这项研究将提供前所未有的机会，以更好地了解从复杂混合物中分离肽，并将知识应用于其他肽，如牛奶中天然存在的生长因子。

Bovine milk proteins are now recognized as a source of peptides having biological activities such as antihypertensive, immunomodulating, lipid and mineral-binding ant antimicrobial. These so-called bioactive peptides are increasingly used as health ingredients in food systems or as supplements. The bioactive peptides are characterized by different charge (cationic, anionic, neutral) and molecular weight values (500-2000 Da) can be produced by enzymatic hydrolysis. The main problem associated with the production of bioactive peptides is to find a process to purify them from a complex mixture in order to increase their potency. The present work is based on the hypothesis that a membrane-based process integrating size, charge and solubility as separation parameters can successfully achieve the purification (>95%) of peptides from complex mixture. The aim of the work is to develop a membrane-based purification procedure for cationic, anionic and neutral peptides from milk. The objectives of the project will be to (1) Evaluate the potential of the different NF membrane materials commercially available for the separation of acidic peptides from complex mixtures; (2) Characterize the effect of the presence of polyelectrolytes (polysaccharides) on solubility, secondary structure and peptide-peptide interactions in b-LG peptide mixtures and NF fractions;(3) Characterize the binding profile of b-LG peptides on the selectivity of NF separations; (4) Validate a separation approach combining NF and pre-treatments with complex systems such as complete milk or whey protein hydrolysates. This research will provide un-precedent opportunities to better understand the separation of peptides from complex mixtures and to apply the knowledge to other peptides, such as growth factors, naturally-occurring in milk.