resumo
The extraction of phenolic compounds from walnut leaves (Juglans regia L.) was optimized using heat-assisted extraction and deep eutectic solvents based on choline chloride and carboxylic acids. A preliminary solvent screening was performed using a selected group of carboxylic acids as hydrogen bond donors, showing that the highest extraction yield of phenolic compounds was obtained using choline chloride mixtures with butyric or phenylpropionic acid at a mole ratio 1:2, with 20% of water (w/w). The extraction conditions (time, temperature and water proportion) were then optimized by an experimental design, assisted by response surface methodology. To evaluate the response, the three most abundant compounds identified by HPLC (neochlorogenic acid, quercetin 3-O-glucoside and quercetin O-pentoside) were quantified. Additionally, the solid/liquid ratio effect at the optimal conditions, in dose-response format, was studied in view of its upscale, not showing any significant decrease until 140 g/L. The results here presented provide valuable information towards the design of a process in a pre-industrial form for the extraction of phenolic compounds from J. regia leaves using deep eutectic solvents.
palavras-chave
RESPONSE-SURFACE METHODOLOGY; MICROWAVE-ASSISTED EXTRACTION; TEMPERATURE MIXTURES LTTMS; VIRGIN OLIVE OIL; IONIC LIQUIDS; OPTIMIZATION; ANTIOXIDANT; RECOVERY; DESIGN; FLAVONOIDS
categoria
Agriculture
autores
Vieira, V; Prieto, MA; Barros, L; Coutinho, JAP; Ferreira, ICFR; Ferreira, O
nossos autores
Vanessa Vieira
InvestigadorGrupos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
The authors thank the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), V. Vieira (SFRH/BD/108487/2015) grant and L. Barros contract. To project POCI-01-0145-FEDER-006984 - Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) - and by national funds through FCT - Fundacao para a Ciencia e a Tecnologia. To project CICECO-Aveiro Institute of Materials POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. This work is funded by the European Structural and Investment Funds (FEEI) through POCI, within the scope of Project POCI no 030463. To Xunta de Galicia for financial support for the post-doctoral researcher of M.A. Prieto.