Optimising turmeric quality through combined infrared and hot air drying (IRHAD) using WASPAS based on RSM

Combined infrared and hot air drying (IRHAD) are widely used due to their affordability, simplicity, and efficient heat dispersion. This work aims to decrease the moisture content and the colour difference (ΔE), influencing the quality of turmeric drying. The drying optimisation conditions were determined by the WASPAS technique based on RSM, with an entropy weight that had the highest Q value of 0.8999 and a coefficient (R2) of 0.9396, suggesting a robust correlation. The results were a temperature of 70 °C, an air velocity of 1.5 m/s, a drying time of 137 minutes, and an infrared power of 1500 watts. This combination leads to a moisture content of 3.14% and ΔE of 20.43. Meanwhile, the MAPE values are at an excellent level of 3.640 for moisture content and 1.422 for ΔE. These conditions can be used to improve product quality and long-term shelf life.