ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Green extraction of phenolic compounds from grape pomace by deep eutectic solvent extraction: physicochemical properties, antioxidant capacity

Victoria Vorobyova, Georgii Vasyliev, Margarita Skiba, Svitlana Frolenkova, Julia Zaporozhets, Olena Gnatko, and Olga Linyucheva

Chemical Technology Department, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kiev, Ukraine

E-mail: vorobyovavika1988@gmail.com

Received: 24 September 2022  Accepted: 23 November 2022

Abstract:

Herein, new function-oriented deep eutectic solvents (DESs) with on l-proline or betaine and DL-lactic acid were designed extraction of polyphenol compounds from grape pomace. The formations of new hydrogen between the two components of DESs were evidenced by FTIR and ¹H NMR spectra. Physicochemical characteristics of deep eutectic solvents under the effect of water on density, viscosity, electrical resistance have been revealed. The betaine-based DES could changes the electrical resistance depending on the concentration of water. The feasibility of using ultrasound-assisted extraction of phytochemicals combined with betaine-based and proline-based DES as a green chemistry technique to improve extraction of green (polyphenols) compounds from grape pomace was evaluated. Grape pomace extracts were analyzed by LC-DAD-MS to identify extracted compounds and analyze the impact of type DES on compound chemical profile. LC results indicated that ultrasound-assisted extraction of phytochemicals using betaine-based and proline-based deep eutectic solvent application allowed enhanced hydroxycinnamic acids extraction, while the use of proline-based DES resulted in a more diverse compound profile. The highest recovery efficiencies were recorded with DESs giving the highest total phenolic content (80–92 mg EGE//g d.w), total flavonoid content (47–51 QUE/g d.w), antiradical activity (80% at 100 mg/ml) and reducing power (310–468 mg ASE/g extract). Scanning electron microscope (SEM) results further verified DESs intensified the destruction of cell wall structure, and thereby allowed greater release of polyphenolic from grape pomace.

Keywords: Valorization; Antioxidants; Green extraction; Natural deep eutectic solvents

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02635-w

Chemical Papers 77 (5) 2447–2458 (2023)