Oil phase-driven nanoemulsions improve CoQ10 stability, in vitro bioaccessibility and ex vivo intestinal uptake

Coenzyme Q10 (CoQ10) exhibits important bioactive and health-promoting functions, yet its poor water solubility and low bioaccessibility restrict its wider application in food and nutraceutical formulations. In this study, CoQ10-loaded nanoemulsions were fabricated using high-pressure homogenization with three edible oil phases (sunflowerseed oil, flaxseed oil, and soybean oil) to elucidate how oil phase composition governs physicochemical behavior, digestive fate, and absorption. All nanoemulsions showed high encapsulation efficiency (98.2%, 97.8%, and 98.0%), while flaxseed oil produced the smallest droplets (98.9 nm), followed by sunflowerseed (143.6 nm) and soybean oils (171.6 nm). All formulations exhibited strong thermal, pH, and storage stability with high absolute zeta potentials (>60 mV). During in vitro digestion, sunflowerseed (49.6%) and flaxseed (53.0%) oil nanoemulsions achieved markedly higher CoQ10 bioaccessibility than soybean oil (24.7%), indicating improved micellarization efficiency driven by lipid composition. Ex vivo rat intestinal studies further demonstrated that flaxseed oil nanoemulsions promoted the highest CoQ10 absorption (32.4%), with sunflowerseed (32.0%) and soybean (26.7%) showing slightly lower values. Collectively, the results show that rational engineering of the oil phase can substantially enhance the stability, bioaccessibility, and intestinal absorption of CoQ10, offering a mechanistic basis for designing next-generation lipid-based delivery systems for poorly soluble bioactives.