Inverse method to sequentially estimate temperature-dependent thermal conductivity of cherry pomace during nonisothermal heating

• A rapid method to estimate thermal conductivity of foods above 100 °C is presented.
• Specific heat of cherry pomace increased with moisture (25–70%) and temperature.
• Thermal conductivity increased with temperature (25–125 °C) and moisture content.
• Thermal diffusivity increased with temperature and decreased with moisture.

Fruit and vegetables are a rich source of many bio-active compounds from which value-added nutraceuticals can be produced. The objective of this work was to estimate temperature-dependent thermal properties of cherry pomace. Differential scanning calorimetric was used to estimate the specific heat. Samples of tart cherry pomace at different moisture contents were canned and heated at 126.7 °C in a steam retort. Ordinary least squares and sequential estimation methods were used for estimating the parameters in MATLAB with Comsol. Thermal conductivity at 25 °C (k1) and 125 °C (k2) during 90 min heating for 70%, 41% and 25% MC were: 0.49 and 0.55; 0.20 and 0.39; and 0.15 and 0.28 W/m °C, respectively, with errors less than 3%. Results are useful for (a) processors desiring to use cherry pomace to make value-added by-products at elevated temperatures common in extrusion and other food drying methods; and (b) researchers desiring a convenient, rapid method to estimate thermal properties of thick and solid foods at elevated temperatures under dynamic conditions.