Influence of Manothermosonication on the Physicochemical and Functional Properties of Ferritin as a Nanocarrier of Iron or Bioactive Compounds.

Ferritin is a multisubunit protein with a hollow interior interface and modifiable surfaces. In this study, the manothermosonication (MTS) technology was applied to apo-red bean seed ferritin (apoRBF) to produce the MTS-treated apoRBF (MTFS). MTS treatment (200 kPa, 50 °C, and 40 s) maintained the spherical morphology of apoRBF (12 nm), but reduced the content of α-helix structure and increased the content of random coil structure, and correspondingly decreased the ferritin stability. The MTS treatment also affected the ferritin's iron storage function by decreasing its iron oxidative deposition activity and increasing the iron release activity. Importantly, the disassembly and reassembly properties of the MTFS induced by pH changes were retained, which facilitated its usage in encapsulation of tea polyphenol-epigallocatechin gallate (EGCG) into the ferritin by a relatively benign pH conversion routine (pH 3.0/6.8). In addition, the water solubility of the MTFS was increased, leading to the improved encapsulation efficiency of the EGCG molecules. This study will facilitate the ferritin modification and functionalization by MTS to design a protein variant to be used as new scaffold for iron and bioactive compounds.