Identifying infrared radiation as the external heat source during fig slice drying: A heat and mass transfer perspective

This research clarified the positioning of infrared radiation heat sources by studying the heat and mass transfer mechanism during drying process. First, the coupled model reasonably simulated fig slices’ moisture migration and temperature change (R2 > 0.916). For infrared radiation coupled hot air drying (IR+AD), the external heat source model more accurately predicted the drying process, yielding heat and mass transfer AAD of 13.96% and 6.74%, respectively. Moreover, the IR+AD process was completed in a mere 40 min, compared to 100 min for hot air drying (AD) alone. The pectin of fig slices dried by IR+AD was well retained, and the ratio of soluble sugars and organic acids was moderate (6.73). Additionally, the microstructure of cell wall and fig slice dried by IR+AD was more uniform than other drying methods. Overall, infrared radiation, as an external heat source, accelerated the drying process of fig slices and effectively improved the sensory quality and texture feature of dried fig slices.