Optimization and Kinetic Studies of Ultrasound-Assisted Extraction on Polyphenols from Satsuma Mandarin (Citrus Unshiu Marc.) Leaves

The present article includes the Ultrasound-Assisted Extraction (UAE) of Citrus unsiu Marc. leaves rich in polyphenols. The best possible combinations of solvent, pH of the media, solvent/solid ratio, extraction time, extraction temperature and particle size were obtained for the maximum extraction of Total Phenolic Compounds (TPC) and Total Flavonoid Compounds (TFC) by using One-Factor-at-a-Time (OFAT) approach.  The optimum extraction conditions of TPC were as follows: pH 4 in water; solvent/solid ratio of 20:1; extraction time, 54 min; and extraction temperature, 53ºC. On the other hand, pH 2 in water, solvent/solid ratio of 42:1, 48 min and 58ºC were found to be the optimal conditions for the extraction of TFC.  The solvent selection was the most effective parameter for the related system.  Additionally, several kinetic models (Film theory, Peleg model, first-order mechanism model and second order mechanism model) were employed to examine the kinetics of UAE.