Solubilization of β-carotene with oat β-glucan octenylsuccinate micelles and their freeze-thaw, thermal and storage stability

Abstract

Self-aggregating polymeric micelles are novel promising vehicles to solubilize and targeting delivery hydrophobic food ingredients. Solubilization of β-carotene with octenylsuccinate oat β-glucan (OSG) micelles, in terms of the apparent solubility of β-carotene ([S]β-car), was investigated in this study. Its dependence on the degree of substitution (DS) and molecular weight (Mw) of OSG and stirrer input power (IP) was explored with the aid of response surface methodology (RSM). More importantly, the freeze-thaw, thermal and storage stability of β-carotene-loaded OSG micelles were determined. Results from RSM revealed that the maximum [S]β-car (12.84 μg/mL) encountered with the intermediate DS (0.0183), high Mw (17.1 × 104 g/mol) and IP (4.3 W). TEM images evidenced a minor deformation of OSG micelles upon β-glucan solubilization. In terms of size and polydispersity index, β-carotene-loaded OSG micelles exhibited good thermal stability, intermediate freeze-thaw stability and inferior storage stability. Furthermore, regarding to the retention of β-carotene, β-carotene-loaded OSG micelles were susceptible to thermal treatment and storage but kept stable against freeze-thaw treatment, but presented nice freeze-thaw stability. The loss of [S]β-car upon thermal treatment and storage was of temperature and time dependence. These results cast new light on the possible fortification of insoluble ingredients by OSG micelles in aqueous food systems.