Easy Fabrication of Bovine Serum Albumin/Astragalus Membranaceus Oil Microcapsules through a Sonochemical Method

Abstract

AbstractIn the research, bovine serum albumin/astragalus membranaceus oil (BSA/AM) core‐shell microcapsules were prepared using the sonochemical method. The energy provided by ultrasound was used to initiate the cross‐linking reaction of the sulfhydryl groups of cysteine residue in BSA to form a disulfide bond, thereby encapsulating the core material‐AM. The core‐shell structure and morphology of the BSA/AM microcapsules were confirmed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. The microcapsule size was determined by dynamic light scattering (DLS). The composition and loading rate of AM were characterized through Fourier transform infrared spectroscopy (FT‐IR) and thermogravimetric analysis (TGA). The hardness and Young's modulus were measured using nanoindentation. And the release performance of BSA/AM microcapsules was investigated by ultraviolet‐visible spectrophotometer (UV‐Vis). The TEM and SEM results show that the BSA/AM microcapsules are spherical with a narrow size distribution. A core‐shell structure and a smooth microcapsule surface were clearly observed. The DLS results show that the microcapsules size and shell thickness are ca. 300 nm and 40 nm, respectively. The FT‐IR results indicate that the shell was formed by denaturing the cross‐linking of BSA under ultrasonic irradiation conditions. The loading rate of AM, approximately 67.6 %, was calculated by TGA. Based on nanoindentation, the hardness and Young's modulus are 0.0107 GPa and 0.1477 GPa, respectively. In terms of the release performance, all astragalus membranaceus oil can be almost released during the time period of four hours.