Ultrasonic-assisted Processes to Recover Phenolics from Watermelon Rinds

Abstract

A combination of Ultrasonic-Assisted Extraction (UAE) and Natural Deep Eutectic Solvent (NADES) was employed to recover phenolic compounds from watermelon rind powder. Among the various NADES formulations tested, the most efficient formulation in terms of extraction effectiveness, as determined by Total Phenolic Contents (TPC), was the one derived from lactic acid and 1,2–propanediol. Single-factor experiments were systematically conducted to evaluate the impact of different UAE parameters, including the liquid-to-solid ratio, ultrasonic power, water content in NADES, and extraction duration, on TPC. The favourable conditions for the UAE process using the lactic acid and 1,2–propanediol-based NADES were found to be as follows: a liquid-to-solid ratio of 60 ml/g, 20% water content in NADES, a temperature of 30 °C, and an extraction duration of 15 minutes. This research presents an efficient, environmentally friendly, and practical method for the retrieval of phenolic compounds from watermelon rind powder.