Monodisperse food-grade water-in-oil-in-water (W-1/O/W-2) double emulsions containing either trans-resveratrol (RSV) or vitamin B-12 were prepared with high encapsulation efficiencies. Two techniques were employed: Conventional and membrane emulsification (ME). Encapsulation efficiency (EE) and storage release with time were determined. The emulsions were characterized by droplet size distribution, stability (by Turbiscan analysis) and rheological behaviour. EE was determined by RP-HPLC using UV-vis and fluorescence detectors. Mechanical agitation leads to polydisperse emulsions, while ME gives emulsions with uniform droplets of 59.82 +/- 0.21 mu m controlled mean size and span values in the range of 0.87-0.90. The EE for both bioactive compounds was considerably higher with ME, resulting in an initial increase of 24.7% for W-1/O/W-2 double emulsions containing RSV and of 8% for emulsions containing vitamin B-12. Droplet size control by ME and appropriate formulation parameters are major factors for a successful production of functional foods with specific rheological behaviour for a wide range of applications. (C) 2015 Elsevier Ltd. All rights reserved.