Thermal Conductivity Measurement and Prediction of Particulate Foods

There is reason to question some of the published thermal conductivity data for particulate foods. It is argued in this article, based on thermal conductivity bounds analysis, that the thermal conductivity of particulate foods should range between 0.03 W m–1 K–1 and 0.30 W m–1 K–1 (provided the porosity is greater than 25%), and that any data outside this range should be rejected. This argument was supported by data for five foods measured as part of this study (cocoa powder, corn starch, whole milk powder, sucrose, and wheat flour), and the majority of published data for particulate foods do indeed fall within this range. The geometric model was found to provide the most accurate thermal conductivity predictions of the models considered, and is recommended for use in first approximation predictions.