ABSTRACT Muntingia calabura , whose leaves are rich in phenolic and flavonoid content, was studied for the synergistic effects of UV‐C pretreatment during microwave drying (from 200 watts to 360 watts). Fresh leaves of the plant were subjected to UV‐C pretreatment for durations of 5, 10, 15 and 20 min. The results were further used to evaluate the leaf drying kinetics, energy performance and quality characteristics. Results showed that moderate UV‐C (5–10 min) in conjunction with moderate microwave (200 W) drying improved drying performance. Improvements were indicated by higher effective moisture diffusivity, lower activation energy, decreased drying time and reduced energy consumption. Extended UV‐C treatment (15–20 min) with high microwave power resulted in tissue damage, pigment loss, and decreases in model performance. The Midilli model was the best fit ( R 2 = 0.999) among semi‐empirical thin‐layer models for all time and energy treatments. Moderate UV‐C pretreatment improved retention of phytochemicals and maintained optical properties. Overall, the research has shown for the first time that UV‐C assisted microwave drying is a novel and efficient method for the sustainable preservation of M. calabura leaves.
Ramanathan et al. (Wed,) studied this question.