Effects of pressure on charge transport in protein powders

Abstract

Conductivity has been measured in d.c. experiments on hydrated bovine serum albumin (BSA) in the pressure range 10–500 MPa and at room temperature. Interfacial and bulk conductivities were determined by detailed measurements on samples equilibrated with 81% relative humidity as a function of pressure. It is revealed that while the interfacial conductivity is insensitive to it, the bulk conductivity decreases exponentially with pressure up to at least 400 MPa. The exponential decrease of bulk conductivity can be attributed to squeezing adsorbed water out of strategically important positions along the conduction pathway(s).