Solid Food Thermal Conductivity Determination at High Temperatures

Thermal conductivity of carrots and potatoes was measured using a line heat source probe adapted for measurements to 130°C. Fastest response and rapid attainment of linearity in temperature rise vs In time plots, were obtained with a silicone oil-filled probe with an uninsulated thermocouple junction. Custom designed electronics to amplify thermocouple output, and computer control of measurements, data acquisition and analysis resulted in 0.4% data repeatability (two standard deviations) for calibration standards. Thermal conductivity of carrot and potato vs temperature agreed well with the published volume fraction model for multi-component foods.