Computed tomography (CT) using synchrotron radiation-sourced X-ray was applied to observation of ice grains in frozen food. At SPring-8 we developed a piece of equipment for keeping specimens in frozen state during the CT measurements, in which vapor of liquid nitrogen blew on the specimen. This capability enabled non-destructive observation of three-dimensional structures of ice grains in frozen specimens of tuna and soybean curd.
The effect of oil-droplet size distribution on the lipid oxidation in oil-in-water emulsions was theoretically examined based on the autocatalytic rate equation. The computational assessment involved lipid droplets coated with a surfactant comprising a hydrophobic moiety. Although the lipid oxidation rate showed a decreasing trend as the oil-droplet size decreased, the polydispersity of the oil-droplet size scarcely affected the lipid oxidation process for oil-droplets of median diameter ranging between 100 nm and 3 μm.
Dynamic binding capacity (DBC) of model proteins in ion-exchange chromatography was analyzed based on a simplified pore diffusion model in order to develop a simple method for designing a capture chromatography process. A dimensionless parameter, F0＝u0dp2/(ZDm) was derived from the pore diffusion model, where u0 is the superficial velocity, dp is the particle diameter, Z is the column bed height, and Dm is the molecular diffusion coefficient. Breakthrough curves of model proteins (lysozyme and immunoglobulin G) were measured for cation exchange chromatography columns of two different particle sizes (dp＝34 and 90 μm) at various temperatures (8, 13, 18, 23 and 28℃). The efficiency E＝DBC/SBC values calculated from the experimental data were well correlated to F0 (SBC＝static binding capacity). The E-F0 curve was found to be useful for designing efficient capture processes of proteins.