The chemical composition and antioxidant and release properties of a black rice (Oryza sativa L.)-loaded chitosan and polyvinyl alcohol composite

A bioactive compound was successfully extracted from black rice (Oryza sativa L) using a solvent extraction process. It was loaded into a chitosan and polyvinyl alcohol-based hydrogel composite at 10, 20 and 30 wt%. The total phenolic content was estimated as 1-4 mg GAE/g extraction. An SEM investigation revealed that the surface pores indicated interfacial adhesion between the bioactive compound and hydrogel composite. There was no significant change in thermal properties. Then, the bioactive compound loaded into the hydrogel composite presented swelling behavior of 600-1200% within 48 h. With the presence of the bioactive compound in the hydrogel composite, greater antioxidant properties were present as investigated by DPPH, ABTS and FRAP assays. Furthermore, the in vitro release characteristic ranged from 60 to 80% for 60 min. Preliminary investigation can be used to explain why a bioactive compound loaded into a chitosan and hydrogel composite has attracted interest in pharmaceutical and cosmetic research. (C) 2017 Elsevier B.V. All rights reserved.