Evaluation of stability of bixin in nanocapsules in model systems of photosensitization and heating

- Stability of bixin in lipid-core nanocapsules.
- Photosensitization and heating in model systems.
- Technique of interfacial deposition of preformed polymer.
- Encapsulation increased the stability of bixin.

Bixin is a good quencher of singlet oxygen, but is unstable at high temperatures and has low solubility in water. The aim of this study was to evaluate the stability of bixin in lipid-core nanocapsules (BIX-LNC) during photosensitization (5-25 °C) and heating (65-95 °C) in model systems of ethanol:water (2:8). The BIX-LNC were prepared by the technique of interfacial deposition of preformed polymer, with a mean diameter (D4,3) of 195 ± 27 nm. During photosensitization in air-saturated conditions, free bixin and BIX-LNC exhibited activation energies of 7.09 and 11.48 kcal/mol, respectively, and in the absence of oxygen exhibited activation energies of 8.96 and 16.31 kcal/mol, respectively. During heating, free bixin and BIX-LNC showed activation energies of 15.06 and 23.81 kcal/mol, respectively. The activation energies for BIX-LNC were superior to those of free bixin in both the photosensitization and heating experiments, suggesting that encapsulation increased the stability of bixin.