In vitro bioaccessibility of ergocalciferol in nanoemulsion-based delivery system: the influence of food-grade emulsifiers with different stabilising mechanisms

The effect of emulsifier type on the in vitro bioaccessibility of ergocalciferol-loaded nanoemulsions was examined (mouth, stomach and small intestinal phases). Oil-in-water nanoemulsions were prepared using emulsifiers with different stabilising mechanisms: decaglycerol monooleate (MO7S; steric), modified lecithin (ML; electrostatic), sodium caseinate (SC; electrosteric) and ML-MO7S (combined electrostatic and steric). The droplet size, size distribution, ζ-potential and microstructure of nanoemulsions during digestion depended on the emulsifier type. The fate of lipid in the small intestinal phase also relied on the emulsifier type, with the free fatty acids release rate decreasing in the following order: MO7S  >  ML-MO7S  >  ML  >  SC. The ergocalciferol bioaccessibilities in nanoemulsions prepared using MO7S (62%), ML (64%) and ML-MO7S (65%) were similar and significantly higher than that stabilised by SC (12%). No significant loss of ergocalciferol was observed in all nanoemulsions after full digestion; they were chemically stable against digestion conditions, regardless of the emulsifier type.