Encapsulation of testosterone and its aliphatic and aromatic dimers by milk beta-lactoglobulin.

•Encapsulation of testosterone and its dimers by milk beta-lactoglobulin was studied.•Steroid-binding sites were located on beta-lactoglobulin.•Testosterone showed stronger affinity toward protein complexation than its dimers.•Steroids alter protein morphology causing increase in protein diameter.•Milk beta-lactoglobulin can be used as steroid carrier.