Formulation characteristics of triacylglycerol oil-in-water emulsions loaded with ergocalciferol using microchannel emulsification

Ergocalciferol is one important form of vitamin D that is needed for proper functioning of the human metabolic system. The study formulates monodisperse food grade ergocalciferol loaded oil-in-water (O/W) emulsions by microchannel emulsification (MCE). The primary characterization was performed with grooved MCE, while the storage stability and encapsulating efficiency (EE) were investigated with straight-through MCE. The grooved microchannel (MC) array plate has 5 x 18 mu m MCs, while the asymmetric straight-through MC array plate consists of numerous 10 x 80 mu m microslots each connected to a 10 mu m diameter circular MC. Ergocalciferol at a concentration of 0.2-1.0% (w/w) was added to various oils and served as the dispersed phase, while the continuous phase constituted either of 1% (w/w) Tween 20, decaglycerol monolaurate (Sunsoft A-12) or beta-lactoglobulin. The primary characterization indicated successful emulsification in the presence of 1% (w/w) Tween 20 or Sunsoft A-12. The average droplet diameter increased slowly with the increasing concentration of ergocalciferol and ranged from 28.3 to 30.0 mm with a coefficient of variation below 6.0%. Straight-through MCE was conducted with 0.5% (w/w) ergocalciferol in soybean oil together with 1% (w/w) Tween 20 in Milli-Q water as the optimum dispersed and continuous phases. Monodisperse O/W emulsions with a Sauter mean diameter (d(3,2)) of 34 mm with a relative span factor of less than 0.2 were successfully obtained from straight-through MCE. The resultant oil droplets were physically stable for 15 days (d) at 4 degrees C without any significant increase in d(3,2). The monodisperse O/W emulsions exhibited an ergocalciferol EE of more than 75% during the storage period.