Development and Numerical Simulation of a Coupled Kinetic Model for Potato Starch Saccharification Under Far-Infrared Intermittent Microwave Convective Drying

Leveraging the high starch content of potatoes, this study developed a model for the hydrolysis of gelatinized starch by β-amylase under coupled microwave, far-infrared, and convective drying. Experiments were conducted using Microwave Convective Drying (MCD), Far-Infrared Microwave Convective Drying (FIR-MCD), and Far-Infrared Intermittent Microwave Convective Drying (FIR-IMCD), all employing a microwave power density of 3.2 W/g. Numerical simulations performed with COMSOL Multiphysics 6.0 systematically analyzed the starch hydrolysis process and key performance parameters under the MCD, FIR-MCD, and FIR-IMCD protocols. The simulation results indicated that compared to MCD and FIR-MCD, the FIR-IMCD process resulted in a lower final maltose content in the samples. In contrast, FIR-IMCD significantly enhanced both the efficiency and uniformity of saccharification during drying, increasing the average starch conversion rate from 46% to 51%. The maximum increase in maltose yield per sample reached 9.3%. Furthermore, FIR-IMCD achieved better temporal synchronization between the concentration of gelatinized starch and β-amylase activity, while the saccharification conversion time was substantially reduced by approximately 81.66%.