Implementation of subcritical water extraction with natural deep eutectic solvents for sustainable extraction of phenolic compounds from winemaking by-products

• Published in: Food research international 2020-11, Vol.137, p.109728-109728, Article 109728
• Main Authors: Loarce, L., Oliver-Simancas, R., Marchante, L., Díaz-Maroto, M.C., Alañón, M.E.
• Format: Article
• Language: English
• Subjects: Bioactive compounds; NADESs; Phenols; Plant Extracts; Solvents; Subcritical water extraction; Vitis; Water; Winemaking by-products
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2020.109728

[Display omitted] •Recovery of valuable compounds from by-products enhance the food chain sustainability.•Grape pomace is a natural source of phenolic compounds with biological activities.•The implementation of subcritical water extraction and NADES was proposed.•Optimization pointed out the use of ChClU 30% at 100 °C as the best extraction conditions.•Implementation of subcritical water and ChClU led to highly efficient and green method. In attempt to recover valuable phenolic compounds from grape pomace by-products, a new implemented methodology has been proposed. The subcritical water extraction technique has been implemented with the use of emerging eco-solvents such as natural deep eutectic solvents (NADESs). The extraction efficiency of different NADESs were screened. Among them, choline chloride containing urea as hydrogen bond donor was selected (ChClU). However, due to pressurised system and the viscosity of NADESs, ChClU could not be used as truly solvent but as a solvent modifier in an promising percentage of 30%. The optimum extraction temperature for the isolation of phenolic compounds was 100 °C since extractions above this temperature implied the loss of the original composition of grape pomace due to thermaldegradation reactions and neoformation of Maillard compounds. The employ of subcritical water combined with 30% of ChClU led to a significant rise of extracted phenolic compounds quantities in comparison with the solely use of subcritical water. Among them, the extraction of catechin and epicatechin suffered an increase of 45.05 and 47.98% respectively, so this implementation led to highly efficient and truly eco-friendly extraction method. The implementation of subcritical water with NADESs to extract valuable compounds from winery by-products has not been applied until now.