ULTRASOUND-ASSISTED DEEP EUTECTIC SOLVENT EXTRACTION OF PHENOLIC COMPOUNDS FROM ROSE MYRTLE

Abstract

Rose myrtle fruits contain high levels of phenolics and other bioactive compounds. To increase the extraction efficiency of phenolic compounds, ultrasound-assisted- deep eutectic solvents (DESs) was proposed. First of all, six different DESs were used in this research and compared with traditional solvents (ethanol, methanol, and water), and the most suitable solvents for extracting phenolic compounds from rose myrtle fruits was choline chloride: urea (molar ratio of 1:2). Then, the Box–Behnken design was used to find the optimal extraction conditions (ultrasonic power (X₁), solid to liquid ratio (X₂), and extraction time (X₃)) for the achievement of high total phenolic contents (TPC) and antioxidant activity (IC50). The results showed that the optimum ultrasound assisted-DES extraction parameters to achieve the highest TPC and antioxidant activity (IC50) (85.19 mgGAE/g fresh fruit and 2.31 mg/g, respectively) were X₁ of 233 W, X₂ of 440 mg/ml, and X₃ of 55 min. Compared with traditional maceration extraction, ultrasound-assisted-DES has a higher TPC and antioxidant activity (IC50) and shorter extraction time. Scanning electron microscopy images (SEM) revealed that the dissolution of bioactive components was enhanced from the disrupted cells after ultrasound-assisted-DES extraction. Consequently, the combination of ultrasound-assisted-DESs extraction provide an excellent extraction method for efficient extraction of bioactive components of rose myrtle fruit.