Drying Kinetics and Quality Evaluation of Thai Rice Noodles Using Far-Infrared Radiation

Abstract

This study investigates the drying characteristics and quality (color, texture, water activity, rehydration ratio, and microstructure via scanning electron microscopy) of dried Thai rice noodles using far-infrared radiation. Infrared (IR) radiation to dry rice noodles increases porosity. It will assist retain the shape of the Thai rice noodle and reduce the browning reaction when restored by soaking in hot water. The experiments were conducted with infrared power of 200, 400, and 600 W; air velocity of 1.0 m/s; and distance between the sample and radiator of 200 mm. Then, the drying kinetics of Thai rice noodles dried by far-infrared radiation were investigated. The results showed that the drying of Thai rice noodles with far-infrared occurred when the drying rate decreased. The drying rate was 1.07×10−2–4.92×10–2 gwater/gdry mass·min, and the drying time was 60–270 min. The higher the infrared power, the faster the drying rate and the shorter the drying time. The experimental data were fitted to various thin-layer drying models. The Midilli–Kucuk model was the best model to obtain the highest R2 value, the lowest root mean square error, and c2 values. The average effective moisture diffusivity (Deff)avg increased with increasing infrared power. Quality results, such as color tone, water activity, hardness, and rehydration ratio, were compared with commercially available dried products. Infrared drying was found to improve the quality of the dried noodles.