Beta-lactoglobulin is the predominant whey protein found in bovine milk and milk from other ruminants, accounting for approximately 50% of total whey protein content. It is a globular protein belonging to the lipocalin superfamily with a molecular mass of about 18.4 kDa. The protein features a characteristic beta-barrel structure that enables binding and transport of small hydrophobic ligands including fatty acids, retinol, and cholesterol. In food science it contributes to emulsification, foaming, and gelation properties. It is thermally labile and undergoes denaturation above 70°C, influencing texture and digestibility of dairy products. It has been researched for potential bioactive roles and applications in functional foods.