BIOLOGICAL VERIFICATION OF FLUID-TO-PARTICLE INTERFACIAL HEAT-TRANSFER COEFFICIENTS IN A PILOT-SCALE HOLDING TUBE SIMULATOR

Inactivation kinetics of immobilized bovine pancreas trypsin (type III ) was used in conjunction with a finite difference model to verify flu id-to-particle heat transfer coefficients to particulates in a holding tube of a pilot scale aseptic processing simulator operated at temper atures ranging from 90 and 110 degrees C. The enzyme was sealed in a s tainless steel capsule, which was pretested to be suitable for high-te mperature, short-time applications, and embedded at the center of a fi nite cylindrical particle. The percentage retention of the enzyme acti vity was calculated by using transient temperatures and their respecti ve D values in a finite difference program. Heat transfer coefficients estimated for the potato particles under similar experimental conditi ons were used as input data. Excellent comparison was observed between predicted and measured percentage retention of enzyme activity.