Isabel MARRUCHO1, Barbara JESUS1, Maria GONZALEZ-MIQUEL2
1Centro de Química Estrutural and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal, Lisbon, Portugal
2Departamento de Ingeniería Química Industrial y del Medioambiente, Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid, Madrid 28006, Spain, Madrid, Spain
Seaweeds are naturally abundant and are spread all over the globe. They have several biologically active secondary metabolites of great interest. Therefore, the interest of their exploitation has increased over the years. In this work Sargassum muticum was the algae employed as biomass and the aim was to extract phenolic compounds (PCs) and the pigment (fucoxanthin) using green extraction Solvents .
Several betaine-based, proline-based, and choline-based (deep) eutectic solvents ((D)ESs) were tested for the extraction of PCs. All extracts were evaluated according to the total phenolic content (TPC), total flavonoids content (TFC) and the antioxidant activity. Followed by the HPLC characterization of 9 PCs (gallic acid, 3,4?Dihydroxybenzoic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, salicylic acid, catechin and quercetin). There were a few (D)ESs that showed higher efficiency in comparison with conventional extraction solvents also evaluated. Proline combined with propylene glycol (Pro:PPG) was the best (D)ES according to HPLC results, followed by proline:1,2-butanediol (Pro:1,2-But) and choline:citric acid (ChCl:CA). Pro:PPG presented high selectivity towards the salicylic acid and ChCl:CA towards the gallic acid. Optimizations studies of water content and temperature were performed for the three best (D)ESs, being the optimum conditions at 30 %(v/v) of water and 60 ºC of extraction temperature.
Ultrasound assisted extraction (UAE) and Microwave assisted extraction (MAE) were two intensification methods evaluated as the objective to enhance the extraction yield. They improve the extraction by significantly reducing the extraction time when compared with the conventional solid-liquid extraction even though the extraction yield could be slight lower. The exception was Pro:PPG with MAE where the extraction was significantly higher in comparison with the conventional extraction.
This work was financed by FCT/MCTES (Portugal) through the project PTDC/EAM-AMB/2023/2021 and CQE project (UIDB/00100/2020).
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Continuous design and economic analysis of a Sargassum muticum biorefinery process, Bioresour Technol. 343