The aim of this study is to investigate the application of ultrasound in the extraction of betanin from beets (Beta vulgaris) using Deep eutectic solvents (DES). The extraction process was optimized using response surface methodology. The time variable was found to be correlated with the extraction performance. Three DES (choline chloride: urea (CC:U), choline chloride: glycerol (CC:G), and choline chloride: citric acid (CC:Ac)) were studied. The concentration of betanin extracted with CC:U, CC:G, and CC:Ac was 41. 27-67.51, 82.46-104.45, and 50.06-111.93 mg/100 g. The maximum betanin extraction of 111.193 mg/100 g was achieved with CC:Ac in 38 min using 44% DES in water in an ultrasonic bath. These results demonstrate that DESs are excellent solvents for the extraction of betanin with superior efficiency to conventional extraction solvents. Ultrasound significantly improved the efficiency of betanin extraction from beets. However, a higher betanin content in the extracts did not translate into greater active antioxidant capacity, which may be related to the synergistic effects of other compounds present in the beet extracts. This study is the first attempt to optimize the parameters for ultrasound extraction of betanin from B. vulgaris using eutectic solvents.

Deep eutectic solvents (DES) are emerging as green and sustainable solvents for the efficient extraction of bioactive compounds and with that have increasingly attracted attention as environmentally friendly alternatives of traditional organic solvents. In this study, aimed to investigate the application of ultrasound in the extraction of betanin from beets (Beta vulgaris) with DES. The optimization of extraction was performed using the response surface methodology. The time variable was relevant in the performance of the extractions. In this work, three DES Choline chloride: urea (CC:U), Choline chloride: glycerol (CC:G) and Choline chloride: Citric acid (CC: Ac) and were studied. The results demonstrated that DES were excellent solvents for extraction of betanin with superior efficiency to conventional extraction solvents. The concentration of betanin varied from 41.27 to 67.51 mg/100 g with CC-U 82.46 to 104.45 mg/100 g with CC-G and 50.06 to 111.93 mg/100 g with CC-Ac. The optimum point in the extraction of betanin using Choline chloride:Citric acid (CC:Ac) was 111.193 mg/100 g in 38 min and 44% DES in water in ultrasonic bath with temperature of 35 ºC, frequency of 37 kHz and amplitude of 100%W. The use of ultrasound is found to have significant improvement in the extraction efficiency of betanins obtained from beets. However, the higher content of betanins in the extracts did not translate into a greater active antioxidant capacity, as it may be related to the synergism of other compounds present in the beet extracts. This study is the first attempt to optimize the ultrasound parameters to extract Beta vulgaris betanin with eutectic solvents.