Infrared-aided hot-air drying of coconut: Impact on drying kinetics and quality metrics

This study explored various drying techniques and temperatures to analyze their effects on the drying kinetics and quality of copra. The initial moisture content of coconut kernels was 50%–55% (w.b.), which decreased to 6%–8% (w.b.) as a result of the drying process. This study focuses on evaluating the individual and hybrid effects of infrared drying (IRD) and hot-air drying (HAD) techniques to enhance the quality of copra. Three drying methods were used: IRD, HAD, and infrared-assisted hot-air drying (IRAHAD). Coconut pieces were subjected to different drying temperatures (50, 60, and 70°C) with a constant air speed of 2 m/s. Optimal results were achieved by employing the IRAHAD method at 60°C, preserving a crucial fat content of 68.4% essential for increased extraction of oil from copra and comparatively high drying rates. In particular, the drying rates in IRAHAD were twice as high as those in IRD and HAD. At a drying temperature of 60°C, the logarithmic model and the diffusion approximation model were deemed the best fit for HAD and IRAHAD, respectively.

Practical applications

This study demonstrates the efficacy of infrared-assisted hot-air drying (IRAHAD) at 60°C in preserving copra's crucial fat content of 68.4% for optimal oil extraction. By implementing IRAHAD, producers can efficiently dry coconut kernels while maintaining quality, enhancing extraction yields, and improving overall profitability in the coconut processing industry.