Ultrasound-assisted extraction of phenolic acids, flavonols, and flavan-3-ols from muscadine grape skins and seeds using natural deep eutectic solvents and predictive modelling by artificial neural networking

• Published in: Ultrasonics sonochemistry Vol. 79; p. 105773
• Main Authors: Alrugaibah, Mohammed, Washington, Taylor L., Yagiz, Yavuz, Gu, Liwei
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2021; Elsevier
• Subjects: ANN; Antioxidants; Catechin; Choline; Deep Eutectic Solvents; Ellagic; Ellagic Acid; Ethanol; Extraction; Flavonols; Grape; NDES; Original; Plant Extracts; Polyphenols; Solvents; Ultrasound; Vitis; Water; NDES; ANN; SSE; AAE; Grape; RASE; Extraction; Ultrasound; Ellagic
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2021.105773

[Display omitted] •Ultrasound-assisted extraction of 8 phenolics from grape pomace using 9 NDES.•A newly formulated NDES (#1) extracted the highest amount of ellagic acid.•A modified NDES (#3) extracted the highest amount of catechin and epicatechin.•Artificial neural networking favored the extraction optimization and prediction. The objective of this study was to investigate the extraction efficiency of 9 natural deep eutectic solvents (NDES) with the assistance of ultrasound for phenolic acids, flavonols, and flavan-3-ols in muscadine grape (Carlos) skins and seeds in comparison to 75% ethanol. Artificial neural networking (ANN) was applied to optimize NDES water content, ultrasonication time, solid-to-solvent ratio, and extraction temperature to achieve the highest extraction yields for ellagic acid, catechin and epicatechin. A newly formulated NDES (#1) consists of choline chloride: levulinic acid: ethylene glycol 1:1:2 and 20% water extracted the highest amount of ellagic acid in the skin at 22.1 mg/g. This yield was 1.73-fold of that by 75% ethanol. A modified NDES (#3) consisting of choline chloride: proline: malic acid 1:1:1 and 30% water extracted the highest amount of catechin (0.61 mg/g) and epicatechin (0.89 mg/g) in the skin, and 2.77 mg/g and 0.37 mg/g in the seed, respectively. The optimal yield of ellagic acid in the skin using NDES #1 was 25.3 mg/g (observed) and 25.3 mg/g (predicted). The optimal yield of (catechin + epicatechin) in seed using NDES #3 was 9.8 mg/g (observed) and 9.6 mg/g (predicted). This study showed the high extraction efficiency of selected NDES for polyphenols under optimized conditions.