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Abstract：
This study is focused on fractionation of insulin-like growth factor I (IGF-I) and transforming growth factor-β2 (TGF-β2) using a new electro-based membrane process calledelectrodialysis with filtration membranes (EDFM). Before EDFM, different pretreatments were tested, and four pH conditions (4.25, 3.85, 3.45, and 3.05) were used during EDFM. It was demonstrated that a 1:1 dilution of defatted colostrum with deionized water to decrease mineral content followed by the preconcentration of GFs by UF is necessary and allow for these compounds to migrate to the recovery compartment during EDFM. MS analyses confirmed the migration, in low quantity, of only α-lactalbumin (α-la) and β-lactoglobulin (β-lg) from serocolostrum to the recovery compartment during EDFM. Consequently, the ratio of GFs to total protein in recovery compartment compared to that of feed serocolostrum solution was 60× higher at pH value 3.05, the optimal pH favoring the migration of IGF-I and TGF-β2. Finally, these optimal conditions were tested on acid whey to also demonstrate the feasibility of the proposed process on one of the main by-products of the cheese industry; the ratio of GFs to total protein was 2.7× higher in recovery compartment than in feed acid whey solution, and only α-la migrated. The technology of GF enrichment for different dairy solutions by combining ultrafiltration and electrodialysis technologies was proposed for the first time.
摘要：
这项研究的重点是使用一种新的基于电的膜方法（称为过滤膜电渗析（EDFM））对胰岛素样生长因子I（IGF-I）和转化生长因子-β2（TGF-β2）进行分馏。在EDFM之前，测试了不同的预处理，在EDFM期间使用四种pH条件(4.25、3.85、3.45和3.05)。已证明，用去离子水对脱脂初乳进行1：1稀释以降低矿物质含量，然后用UF预浓缩GFs是必要的，并允许这些化合物在EDFM过程中迁移到回收室。MS分析证实了迁移，数量少,在EDFM期间，只有α-乳白蛋白（α-la）和β-乳球蛋白（β-lg）从血清型到恢复室。因此,在pH值为3.05时，回收室中GFs与总蛋白的比例比饲料血清型溶液高60倍，最佳pH有利于IGF-I和TGF-β2的迁移。最后,在酸乳清上测试了这些最佳条件，以证明所提出的工艺对干酪工业主要副产品之一的可行性；回收室中GFs与总蛋白的比率比饲料酸乳清溶液高2.7倍，只有α-la迁移。首次提出了结合超滤和电渗析技术对不同乳制品溶液进行GF富集的技术。
