Nanoemulsion structure and food matrix determine the gastrointestinal fate and in vivo bioavailability of coenzyme Q10.

In this work, we sought to incorporate coenzyme Q10-loaded nanoemulsions into a food system and to understand the impact of food digestion on the in vivo bioavailability of this bioactive compound. We selected octenyl succinic anhydride modified starch as emulsifier to prepare the nanoemulsions (with approximately 200 nm droplet diameter) after comparing with two other food-grade surfactants (whey protein isolate and lecithin) in terms of their colloidal stability during simulated gastrointestinal digestion. The change in ζ-potential revealed that the initial emulsifier might be partially replaced by bile salts under intestinal conditions, and the mixed micelles formed after digestion showed an apparent permeability coefficient of 4.79 × 10-6 cm/s in a rat intestinal epithelial cell line, without compromising the trans-epithelial electrical resistance. In a second step, a high protein beverage that incorporated the coenzyme Q10-loaded nanoemulsion was developed in a food pilot plant. The beverage had a particle size of D4,3 = 18 μm and D3,2 = 2.5 μm, corresponding to its different components. The changes in particle morphology and size distribution were analysed to understand the behaviour of this beverage during simulated gastrointestinal digestion. When coenzyme Q10 was encapsulated into the nanoemulsions and the beverage, its bioavailability in vivo increased 1.8- and 2.8-fold respectively, compared with coenzyme Q10 dissolved in oil. The higher coenzyme Q10 bioavailability in the beverage was probably because of a significantly higher level of lipolytic activity found for beverage than for nanoemulsions during gastrointestinal digestion. These results show the potential of using natural food materials to generate formulations to improve the bioavailability of bioactive compounds. More importantly, we highlight the influence of food digestion (i.e. lipolysis) on the absorption of hydrophobic bioactive components and suggest that food systems can be utilised as a dosage form to further enhance oral bioavailability.