| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 20.39 MB | Adobe PDF |
Advisor(s)
Abstract(s)
Deep eutectic solvents (DES) are a new generation of alternative solvents resulting from the mixture of
two (or more) starting materials where the eutectic temperature of the mixture is considerably lower than
the melting point of the individual components [1]. DES can be considered “designer solvents” due to the
possibility of combining different hydrogen bond acceptors and donors, to obtain solvents with specific
affinity to the target molecules. Among their many applications is the potential use of DES as both
solvents and formulation media of extracts rich in phenolic compounds [2].
In this work, the heat assisted extraction of phenolic compounds from walnut leaves was optimized, using
DES based on choline chloride (CC) and carboxylic acids. To evaluate the response, the main phenolic
compounds present in the extract (acid 3-O-caffeyloquinic acid, quercetin 3-O-glucoside and quercetin
O-pentoside) were determined by HPLC-DAD.
From a preliminary solvent screening, butyric acid (BA) and phenylpropionic acid (PPA) were selected as
hydrogen bond donors. The extraction conditions (time, temperature and water content) were then
optimized by an experimental design, assisted by response surface methodology. Water content was the
most relevant extraction variable, followed by temperature and, lastly, extraction time.
Under the optimized conditions, it was possible to obtain a response of 37.9±4.0 mg/g dw for CC:BA and
31.7±4.2 mg/g dw, for CC:PPA. Compared to the traditional water + ethanol reference solvent, similar or
higher extraction yields were obtained using the selected DES.
Description
Keywords
Citation
Vieira, Vanessa; Prieto, Miguel; Barros, Lillian; Coutinho, João A.P.; Ferreira, Olga; Ferreira, Isabel C.F.R. (2017). Optimization of the extraction of phenolic compounds from walnut leaves using DES. In 10º Encontro Nacional de Cromatografia. Bragança. ISBN 978-972-745-234-7
Publisher
Instituto Politécnico de Bragança