Boron-doped titania for separation and purification of lactoferrin in dairy products

Lactoferrin (LF), a natural iron regulating glycoprotein, exists in animal milk and plays multiple beneficial roles. Bovine LF is obtained by separation and purification from cow's milk, and has been added as a food additive to functional foods and infant formula now. Therefore, accurate analysis of LF in these foods is very important, but there are challenges such as poor selective extraction and separation efficiency. In this work, considering the cis-diol in LF, boron-doped titania (B-doped TiO₂) material was prepared for selectively enrich LF from dairy products. In order to increase the saturation capacity of extracted LF, the amount of boron for doping was optimized, and maximum binding capacity of 63.9 mg g^-1 was achieved when the atomic ratio of B to Ti was 1.65 with improved affinity in terms of K_D value. In addition, the primary parameters affecting extraction efficiency such as extraction time, extraction pH, desorption time, and desorption solution were also optimized. The method of dispersive solid phase extraction based on B-doped TiO₂ combined with ultra-high performance liquid chromatography-ultraviolet detection (UHPLC-UV) was developed and validated. The material greatly reduced the cost of sample pretreatment and the method also was applied to detect the LF in different dairy products such as liquid milk, fermented milk, and infant formula. This method could be used for routine analysis, separation and purification of LF.