Drying kinetics and optimization of quercetrin extraction from melastoma malabathricum leaves

Abstract

The leaves of Melastoma malabathricum were dried and ultrasonicated to produce a high-quality extract. The optimum drying temperature was determined to obtain the highest yield, total phenolics, and flavonoids, especially quercetrin content with antiradical capacity. The Midilli model could explain the drying kinetics satisfactorily. The effective diffusivity of moisture ranged between 2.16 and 10.22 × 10−11 m2s−1, and the activation energy was 49.81 kJ mol−1. The dried leaves were extracted under optimized conditions in terms of particle size, solid-to-solvent ratio, solvent concentration, extraction time, and ultrasonic amplitude of the ultrasound-assisted system. The quadratic model was applied to predict reasonably the yield and quercetrin content in the extract.