Effect of microwave pretreatment on truffle solar drying from an energetic perspective

Drying, an age-old method of food preservation, involves the concurrent exchange of heat and mass, resulting in reduced moisture content. The current study is based on experimental approach to evaluate the impact of combined microwave and solar drying on the drying kinetics and the energy efficiency of truffle drying. This study explores the impact of a 4-min microwave pretreatment on the solar drying of truffle slices. The findings demonstrate that microwave treatment significantly reduces the time required for solar drying. When compared to solar drying without pretreatment, microwave treatment leads to a reduction in drying time ranging from 23.07% to 70.37% at temperatures between 50 and 80°C. The Midilli–Kucuk model is employed to elucidate the experimental results, revealing strong fits with high correlation coefficients and low standard error values. Microwave pretreatment enhances the drying rate of truffle slices, resulting in a higher effective moisture diffusivity compared to untreated slices. The activation energy for drying also decreases from 76.37 to 25.25 kJ/mol after microwave pretreatment. An energy analysis of the drying process underscores that elevating the drying air temperature reduces energy consumption. Furthermore, the proposed microwave pretreatment influences the energy efficiency of the drying process.