Methodology to obtain true thermal conductivity of low porosity food powders

A technique was developed to measure, at a porosity close to zero, the true thermal conductivity of food powders. Samples of low porosities were prepa red by mechanically compressing the food powder using a hydraulic press at pressures up to 3.035 x 10(5) kPa (abs) in specially designed stainless ste el cylinders with a dummy probe in place. Variation in porosity of the samp les was less than 5%. Thermal conductivity was measured as a function of po rosity (0.086 to 0.7), moisture content (0 to 37%, dry basis), and temperat ure (30 to 150 degreesC) by the thermal conductivity probe method. The ther mal conductivity values decreased with an Increase in porosity and increase d with an increase in moisture content and temperature.