Abstract: The effects of different types and concentrations of carrier oil on the stability of nanoemulsion and quercetin bioavailability were studied. Quercetin-loaded nanoemulsions were prepared by high pressure homogenization of medium-chain triglycerides (MCT) or long-chain triglycerides (LCT) as the oil phase with pear adzuki bean protein as the emulsifier. The stability was investigated by light scattering particle size analysis, zeta potential, microscopic observation, physical stability, free fatty acid release and quercetin bioavailability. The results showed that compared with the LCT nanoemulsion, the MCT nanoemulsion showed higher stability and a slower degradation rate of quercetin. The average particle size of the nanoemulsion prepared with 5% MCT was (152.80 ± 1.73) nm compared to (180.42 ± 1.98) nm for the one prepared with 5% LCT. The biological retention rate of quercetin measured using a simulated gastrointestinal model was greatly improved in the MCT nanoemulsion system. This finding will be useful for the design of a more effective delivery system for enhanced quercetin bioavailability.

Key words: quercetin; nanoemulsion; carrier oil; stability; bioavailability