Optimization of the Ultrasonic-Assisted Extraction of Phenolic Compounds, Ferric Reducing Activity and Antioxidant Activity of the Beta vulgaris Using Response Surface Methodology

Phenolic compounds act as receiver of the free radicals and antioxidant activity of the extracts has high correlation with these compounds amount. Ultrasonic-assisted extraction (UAE) presently is an interesting technique for recovering the valuable compounds from the vegetal materials. The aim of this research was optimization of the extraction condition of UAE using response surface methodology (RSM). Effects of extraction time and ultrasound intensity on the total phenolic contents (TPC), antioxidant properties, as well as ferric reducing antioxidant power (FRAP) of Beta vulgaris extract were investigated. The results showed that 92.68% of intensity and 15.85 min were the optimum extraction condition for highest TPC extraction. The amount of TPC, EC50 and FRAP in extract of Beta vulgaris in optimum conditions of UAE were equal to 0.916 mg gallic acid/g of extract, 0.937 mg/mL and 1.20 mmol/mL, respectively. Therefore, results showed that ultrasound intencity has a positive effect on the extraction efficiency of phenolic compounds and ferric reducing antioxidant power, but has a negative effect on the free radical scavenging ability. It can be concluded that the extraction efficacy of Beta vulgaris extract could be enhanced significantly by optimization of the extraction process by means of RSM.