Benzoyl peroxide (BP), used to bleach annatto in cheese whey, was encapsulated within the hydrophobic dispersed phase (phi) of nanoemulsions (NEs) to minimize its degradation and extend its efficacy to minimized usage levels. Three purified, saturated short-chain fatty acids of varying chain lengths: butyric (C4), hexanoic (C6) and octanoic (C8) acid, were chosen as the phi to completely dissolve various concentrations of BP. Stabilization was achieved with different concentrations and combinations of primary emulsifier (E), bovine serum albumin, and coemulsifier (CE), Tween 20. Different ultra-high pressures (UHP) were used to generate a stable NE. The best result was made by keeping these parameters: UHP 210 MPa/phi fraction 4x10-3/ BP 0.04% (w/v) constant, E (without CE) concentration of 0.04% (w/v) for both C4 and C6 or 0.6% (w/v) for C8. Annatto color reduction by 90% was achieved with C4-system using only half the typical concentration of BP used by the industry.