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

Self-aggregating polymeric micelles are novel promising vehicles to solubilize and targeting delivery hydrophobic food ingredients. Solubilization of beta-carotene with octenylsuccinate oat beta-glucan (OSG) micelles, in terms of the apparent solubility of beta-carotene ([S](beta-car)), was investigated in this study. Its dependence on the degree of substitution (DS) and molecular weight (M-w) 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 beta-carotene-loaded OSG micelles were determined. Results from RSM revealed that the maximum [S](beta-car) (12.84 mu g/mL) encountered with the intermediate DS (0.0183), high M-w (17.1 x 10(4) g/mol) and IP (4.3 W). TEM images evidenced a minor deformation of OSG micelles upon beta-glucan solubilization. In terms of size and polydispersity index, beta-carotene-loaded OSG micelles exhibited good thermal stability, intermediate freeze-thaw stability and inferior storage stability. Furthermore, regarding to the retention of beta-carotene, beta-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](beta-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. (C) 2015 Elsevier Ltd. All rights reserved.