Synthesis, characterization, and applications of natural deep eutectic solvents (NADES) in the extraction of phenolic compounds from spent hop

• Grant number: 23/13030-7
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: November 01, 2023
• End date: January 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Stanislau Bogusz Junior
• Grantee: Guilherme da Silva Ribeiro
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/03229-8 - Synthesis, characterization and applications of natural deep eutectic solvents (NADES), AP.PNGP.PI

Abstract

The principles of green chemistry are receiving increasing importance due to the need to reduce the use of classical organic solvents, commonly classified as toxic, explosive, and polluting in industrial processes. In this regard, the use of natural deep eutectic solvents (NADES) is a bold and innovative alternative to replace conventional organic solvents in extraction processes. The objective of this research is to synthesize, characterize, and apply NADES in the extraction of phenolic compounds from an important brewing by-product, the spent hops. For that, the response surface methodology will be employed to synthesize thirty different NADES. After synthesis, the NADES will be characterized in terms of pH, polarity, viscosity, density, Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). The three best NADES obtained in the optimization step will be used as green solvents to obtain ready-to-use extracts rich in phenolic compounds from spent hops. Other extractions using water (100%) and hydroalcoholic solution (60%) will also be performed with spent hops for the purpose of comparing the solvents extraction efficiency. Furthermore, a method for the identification and quantification of phenolic compounds in the extracts will be developed, optimized, and validated using HPLC-MS/MS. The extracts obtained with NADES, water, and hydroalcoholic solution will be evaluated for their stability during one year of storage. Additionally, the principles of green chemistry will be use to calculate the eco-scale of the extraction solvents. It is believed that this research will provide important information about the synthesis, characterization, and application of NADES as alternative, sustainable, and environmentally friend solvents to replace the traditional organic solvents in industrial processes for obtaining plant extracts from spent hop waste, providing a destination and adding value to this industrial by-product. (AU)