Drying Kinetics and Quality Assessment of Thai Rice Noodles Using Hot-Air and 2-Stage Drying Methods

This study investigated the drying kinetics and quality attributes of Thai rice noodles subjected to hot air and 2-stage thin layer drying methods. Hot-air drying experiments were conducted at 40, 50, and 60 °C The 2-stage drying involved an initial infrared drying phase at 200, 400, and 600 W for 120, 90, and 30 min, respectively, followed by hot-air drying at temperatures of 40, 50 and 60 °C. Key quality parameters assessed included color metrics, rehydration ratio, surface morphology, and texture. Results showed that the moisture content during hot-air drying decreased exponentially, with the drying rates varying from 0.0119 to 0.0236 and drying times from 120 to 240 min. The effective diffusion coefficient ranged from 1.3378×10−11 to 2.5796×10–11 m2/s and, drying behavior was well described by Page’s drying model. In contrast, the two-stage drying exhibited a linear moisture decrease during the infrared phase and an exponential decrease during the subsequent hot-air drying. The drying rates ranged from 0.0096 to 0.0376  with drying times ranged between 75 and 300 min. Effective diffusion coefficients for the first and second stages ranged from 4.1045×10–12 to 2.6461×10–11 to 1.5668×10–11 to 4.3220×10–11 m2/s, respectively, with drying kinetics accurately predicted by Singh et al. drying model. Quality analysis revealed that prolonged drying time reduced brightness but increased redness and yellowness. Both drying techniques produced dried noodles exhibiting quality characteristics comparable to commercial products, along with a notably higher rehydration ratio. HIGHLIGHTS The drying of Thai rice noodles was investigated using hot air and 2-stage thin layer drying methods. During hot-air drying, the moisture content dropped exponentially, and Page’s drying model accurately captured the drying behavior. Singh et al. drying model correctly anticipated the drying kinetics, which showed a linear moisture drop during the infrared phase and an exponential decrease during the subsequent hot-air drying. Longer drying times increased redness and yellowness while decreasing brightness, according to quality analysis. Both drying methods yielded dried noodles with a noticeably greater rehydration ratio and quality attributes on par with commercial items. GRAPHICAL ABSTRACT