Drying Characteristics, Process Optimization, and Applied Economic Analysis of Vacuum Microwave Drying of Poria cocos

To explore the vacuum microwave drying (VMD) characteristics of Poria cocos, the drying characteristics, process optimization, and economic analysis of this method were evaluated by multi-index weighted comprehensive scoring and economic comprehensive evaluation methods. Single-factor experiments revealed that the comprehensive quality score of P. cocos peaked at 55°C, 600 W, and -75 kPa when each factor was varied independently. The response surface methodology (RSM) predicted a different optimum: 56.2°C, 609 W, and -77 kPa, yielding a predicted comprehensive score of 0.9955. Within the range of experimental conditions, the maximum drying rate and D_eff value increased with increasing drying temperature and microwave power, and decreased with the reduction of vacuum degree. The drying rate increased first and then decreased with the decrease of moisture, and no obvious constant speed stage was observed. The E_a value of VMD-dried P. cocos was 27.95 kJ/mol, which was lower than that of hot-air drying (HAD), gas jet drying, and vacuum pulsation drying. The Page function effectively predicted the dynamic model of VMD of P. cocos. The economic analysis showed that over a design life of 10 years, the profit created by a single VMD equipment is $2,568,870, which is about four times the profit generated by HAD equipment of the same specification. PRACTICAL APPLICATIONS: This research is conducive to understanding the vacuum microwave drying characteristics of Poria Cocos, grasping the drying process, suitable parameters and economic overview, and providing a reference for the development of P. cocos drying technology.