Drying kinetics and quality characteristics of daylily dried by mid-infrared

Abstract

Abstract Industrially, the use of far-infrared (FIR) as a heat source for drying daylily presents some issues, such as high energy consumption and large loss of nutrients. The use of mid-infrared (MIR) was performed to study the drying of daylily to explore its advantages, with the FIR drying as a comparison. Drying models were established by the drying kinetics, and the changes of nutrition, rehydration ratio (RR) and water migration pattern were researched. The results showed the best-fitting drying model was the Modified Henderson and Pabis model. Under the same temperature, compared with FIR drying, the drying time of MIR drying was shortened by 50%, the effective moisture diffusivity (D eff) was increased by 103%, the drying activation energy (E a) was reduced by 10%, the reducing sugar and ascorbic acid retention rate was increased by 13.9% and 9.7%, respectively. The MIR drying had better RR and water migration characteristics.