A novel Camellia oil microemulsion significantly enhances the bioaccessibility and antioxidant activity of curcumin: a comparative study with macroemulsion.

This study compared a camellia oil-based microemulsion (CUR-ME) with a macroemulsion (CUR-MacE) of identical composition to enhance the delivery of curcumin. The CUR-ME exhibited a nanoscale droplet size (∼12 nm), low polydispersity (PDI < 0.1), and superior physical stability. During in vitro digestion, CUR-ME achieved a 2.6-fold higher bioaccessibility of curcumin (79.5%) compared to CUR-MacE (30.4%). The bioaccessible fraction from CUR-ME also demonstrated significantly stronger retention of antioxidant activity in ABTS and FRAP assays. Thermal analysis confirmed the molecular dispersion of curcumin within the microemulsion and revealed compatible interactions with the camellia oil phase. These findings underscore the microemulsion structure as a decisive factor for improving the bioaccessibility and preserving the antioxidant activity of curcumin, offering a superior delivery strategy for functional foods.