Ultrasound assisted extraction of phenolic compounds from Capparis Ovata var canescens fruit using deep eutectic solvents

The aim of this study is to develop a green procedure that provides high-efficiency extraction of phenolic compounds from Capparis Ovata fruit with Deep Eutectic Solvent (DES) using ultrasound-assisted extraction method. Ten DES combinations were prepared by mixing various proportions of choline chloride (ChCl), Na-acetate and Na-citrate with sugar alcohols, carboxylic acid. These DESs were tested as an effective solvent for recovering phenolic compounds. DES composed of lactic acid combining with ChCl showed the highest efficiency of extraction for phenolic compounds. Optimal extraction conditions were found as follows; 20% water in DES, liquid/solid ratio 20:1 (mL/g), temperature 50℃, and extraction time 30 min. The maximum total phenolic content, total flavonoid content, DPPH inhibition percentage, and ferric reducing power capacity values under optimal conditions were 30.55 ± 0.57 mg GAE/g DW, 13.04 ± 0.4 mg QE/g DW, 98.49 ± 2.51% and 1.79 ± 0.04 (absorbance units), respectively. The concentrations of all phenolic compounds determined by chromatographic method have increased under optimal extraction conditions. Practical applications The application of DES in the extraction of the phenolic compound is an innovative approach for environmentally, friendly, low-costs, and improving extraction efficiency. Caper fruits are known to be rich sources of bioactive compounds. Caper is consumed as food and traditional folk medicines for their health benefits. At previous studies, a green extraction procedure to obtain phenolic compounds from Capparis Ovata var canescens fruit has not been established by using DES. Therefore, this study aimed to improve a green procedure to obtain phenolic compounds with strong antioxidant properties, which could be employed in the food industry. In addition, determination of optimal extraction conditions has been performed to guide large-scale production.