Optimization of Ultrasound-Assisted Obtention of Bluish Anthocyanin Extracts from Butterfly Pea (Clitoria ternatea) Petal Powders Using Natural Deep Eutectic Solvents

This study focused on improving the extraction of anthocyanins from medicinal plants using green solvents, which is important for the food, pharmaceuticals, and cosmetics industries. The goal was to optimize the time (15-50 min), temperature (40-80 °C), and petal/solvent ratio (2.5/7%) for the ultrasound-assisted extraction of anthocyanins from Butterfly Pea (<i>Clitoria ternatea</i>), using a natural deep eutectic solvent (choline chloride/glycerol, ChCl:Gly). The extraction was compared with a simple water extraction. To assess stability, we analyzed the anthocyanin content, antioxidant capacity, and color changes over 21 days. The optimal results were achieved using a temperature of 80 °C for 50 min and a 7% petal/solvent ratio. The CHCl:Gly solvent resulted in higher anthocyanin levels (374.65 mg DGE/L) compared to water (211.63 mg DGE/L). After storing the CHCl:Gly extract at 5 °C, only 16% of anthocyanins were lost, while the water extract lost 38%. The CHCl:Gly extract also showed better antioxidant capacity (156.43 µmol/mL). Color changes were less noticeable in the CHCl:Gly extract, especially when refrigerated. These findings demonstrate the method's effectiveness for producing bioactive extracts, with potential for the food, pharmaceutical, and cosmetic industries.