Novel Mathematical Model With Integrative Optimization for Microwave Drying of Olive Leaves (Olea Europaea) to Enhance Bioactive Compounds Preservation, Antioxidant Activity, and Energy Efficiency

This study optimized the microwave drying of olive leaves by integrating mathematical modeling and proposing a novel drying model, along with a comprehensive analysis of energy efficiency and bioactive compound preservation. Experiments were conducted at microwave power levels ranging from 100 to 1000 W, assessing drying kinetics, energy efficiency, and retention of bioactive compounds. The optimal power of 700 W achieved a drying time of 21 minutes while preserving key bioactive compounds, with TPC, TFC, and antioxidant activity reaching 108.79 mg GAE/g DM, 12.12 mg RE/g DM, and 23.25 mg GAE/g DM, respectively. Several mathematical models from the literature were evaluated, and the Logarithmic, Modified Henderson–Pabis II, and Hii et al. models showed excellent agreement with the experimental data (R² > 0.99). The proposed new model also demonstrated strong predictive accuracy, with high R² values and low root mean square error and reduced chi-square (χ²). The lowest specific energy consumption was 0.236 × 10⁵ MJ/kg H₂O, accompanied by the highest energy efficiency. These results demonstrate that intermediate microwave power provides an optimal balance between energy efficiency, processing time, and bioactive compound preservation, highlighting both practical and economic advantages for olive leaf drying.