Optimization and Characterization of Curcumin Loaded in Octenylsuccinate Oat β-Glucan Micelles with an Emphasis on Degree of Substitution and Molecular Weight

The dependence of the curcumin loading capacity (CLC) of octenylsuccinate oat β-glucan (OSG) micelles on the structural parameters (degree of substitution, DS; molecular weight, Mw) of OSG was unknown and explored in this study. Meanwhile, the curcumin-loaded OSG micelle (COM) was first characterized. The results from response surface methodology revealed that the linear effects of Mw and stirrer input power, as well as the quadratic effect of DS, were significant (p < 0.05). The maximum CLC value of the OSG micelle was obtained as 4.21 μg/mg. Dynamic light scattering showed that the average size and ζ potential of the COM were 308 nm and -10.8 mV, respectively. Transmission electron microscopy and atomic force microscopy evidenced that the COM was elliptical in shape. Fourier transform infrared spectroscopy, differential scanning calorimeltry, and X-ray diffraction revealed that curcumin was loaded in OSG micelles in an amorphous form by interacting with OSG molecules.