Development of a Method Based on Natural Deep Eutectic Solvents for Extraction of Flavonoids from Food Samples

Natural deep eutectic solvents (NADES) are promising green solvents for the extraction of compounds from natural products. This is the first study to use a sample preparation method based on NADES for the extraction of flavonoids (rutin, hesperidin, neohesperidin, naringenin, naringin, quercetin, hesperetin, and chrysin) from fruits, vegetables, and spices. In total, 17 types of NADES based on choline chloride, acetylcholine chloride, choline tartrate, betaine, and carnitine with different compositions were tailored to test their extraction efficiency. Operational conditions such as water content in NADES and liquid/solid ratios were also studied. A response surface methodology was used for multivariate optimization of some extraction parameters. Efficient recovery of extracted flavonoids (higher than 70%) was achieved using a 30% water solution of acetylcholine chloride/lactic acid ratio (2:1) as an extraction solvent. Other conditions for SLE-NADES were as follows: liquid/solid ratio 3:1, extraction temperature 60 A degrees C, extraction time 30 min, and stirring speed 1400 rpm. Each extract was analyzed by UHPLC with UV and MS/MS detection. The developed method was applied for analysis of flavonoids in fruits (cranberry, fruits of Lycium barbarum L., grape, plum, and orange peel), vegetables (onion and broccoli), and spices (mustard, rosemary, and black pepper).