Infrared assisted hot air dryer for turmeric slices:Effect on drying rate and quality parameters

An infrared assisted with hot air dryer (IRHAD) was designed and developed to retain the quality of turmeric during drying. Drying experiments were conducted at three different mode of operation [infrared assisted with hot air drying (IRHAD), infrared drying (IRD), and hot air drying (HAD)] and three different drying temperatures (50, 60 and 70 °C) at fixed air velocity of 2 m/s. It was observed that IRHAD at 70 °C showed higher drying rate and recorded 26.98% and 35.21% lesser drying time than IRD and HAD, respectively. An increase in drying temperature (up to 60 °C) increase the curcumin, oleoresin, colour and starch content and further increase in temperature degrades the quality of the turmeric. IRHAD provided maximum retention of curcumin, oleoresin, and starch content and less colour deterioration at 60 °C temperature compared to IRD and HAD. The drying methods and drying temperatures have significant effect (P ≤ 0.01) on the quality parameters investigated. IRHAD with the drying temperature of 60 °C could be the suitable operating condition to produce better-quality turmeric. [Display omitted] •Infrared assisted with hot air dryer (IRHAD) were developed for turmeric slices.•The performance of IRHAD was superior than IRD and HAD.•IRHAD with a temperature of 70 °C showed less drying time followed by IRD and HAD.•IRHAD with 60 °C drying temperature resulted in the quality parameters retention.