Beta–lactoglobulin–nutrition allergen and nanotransporter of different nature ligands therapy with therapeutic action

β–lactoglobulin is one of the nutrition allergens present in the milk of many mammals, with the exception of human. This protein belongs to the family of lipocalins, consisting of nine antiparallel β–strands (β–A to β–I) and one α–helix. This structure allows it to serve as a nanotransporter of various nature ligands in a pH dependent manner, which allows us to confidently consider it as a reliable carrier of drugs directly into the intestine, bypassing the destructive acidic environment of the stomach. Based on the latest data, this review describes the currently known methods of reducing the allergenicity of beta–lactoglobulin, as well as the mechanisms and methods of forming complexes of this protein with ligands, which emphasizes its importance and versatility and explains the growing interest in studying its properties in recent decades, and also opens up prospects for its practical application in medicine and pharmaceuticals. [Display omitted] •Physical and chemical properties of β–LG are described.•The review presents the latest data characterizing the β–LG as nanotransporter of various nature ligands.•The polymorphism of β–LG genes and the evaluation of useful traits in animals with different β–LG genotypes are discussed.•Modern ways to reduce the allergenicity of β–LG are described in this review.