The influence of microwave drying on drying and rehydration kinetics of Acanthus ilicifolius leaves in tea production

Acanthus ilicifolius, commonly known as Jeruju, is a medicinal herb found in Malaysia, recognized for its anti-inflammatory and antioxidant properties, making it an ideal candidate for healthy tea. This study investigated the crucial drying and rehydration processes of Acanthus ilicifolius leaves in tea production, focusing on drying kinetics and characteristics. Utilizing microwave drying with varying power levels, four mathematical models; Page, logarithmic, Newton, and Midili and Kucuk were employed to analyze drying behaviour, while Peleg and first-order kinetic models were applied to the dried leaves in powder form for a rehydration behaviour assessment. Results demonstrate microwave drying at 1000 W as the fastest, taking only 20 min, while commercial shade drying requires 72 hrs. The Page model best fits the drying behaviour, showing higher R 2 values (0.9840-0.9999) and lower X 2 values (0.0007-0.0048) for both methods. Microwave drying process preservation yields the lowest a* value of -4.16±0.61, and microwave drying post-commercial drying exhibits a DPPH inhibition value of 23.84%. In the rehydration process of the dried leaves, the first-order kinetic model proves most suitable with higher R 2 values (0.8998-0.9943). The study emphasizes the significant impact of the drying method on Acanthus ilicifolius leaves, offering valuable insights for optimizing tea production with this medicinal herb.