β-Lactoglobulin separation from whey protein: A comprehensive review of isolation and purification techniques and future perspectives

Cow milk, although rich in essential nutrients, is a well-known food allergen that can cause allergic reactions in infants and young children. β-Lactoglobulin accounts for 10% of the total protein in milk and 50% of the whey protein, which has high nutritional value and excellent functional properties but is also the main allergen leading to milk protein allergy. Exploring the mechanism of milk allergy and selecting suitable separation and purification methods to obtain high-purity β-LG is the premise of research on reducing allergenicity. In this review, the research progress in membrane technology, gel filtration chromatography, ion exchange chromatography, affinity chromatography, precipitation, and aqueous 2-phase system separation for the separation and purification of milk β-LG is reviewed in detail to promote the further development of milk β-LG separation and purification methods and provide a new method for the development of hypoallergenic dairy products in the future. Among these methods, ion exchange chromatography and gel chromatography are widely used, precipitation is generally used as a crude purification step, and HPLC and membrane technology are used for further purification to improve the purity of allergens.