Development and Box-Behnken design optimization of a green extraction method natural deep eutectic solvent-based for...

Area of Science:

• Agro-food science
• Green chemistry
• Natural product chemistry

Background:

• Agri-food by-products like barley malt rootlets (BMRs) are rich sources of phenolic compounds.
• Traditional extraction methods often rely on organic solvents, posing environmental and safety concerns.
• Green chemistry principles drive the search for sustainable extraction solvents, including natural deep eutectic solvents (NADESs).

Purpose of the Study:

• To develop and optimize an environmentally friendly, cost-effective, and rapid extraction method for phenolic compounds from BMRs.
• To evaluate the efficacy of various NADESs as extraction solvents for these compounds.
• To identify optimal extraction parameters for maximizing phenolic compound yield.

Main Methods:

• Screening of several natural NADESs for phenolic compound extraction from BMRs.
• Optimization of extraction conditions using a Box-Behnken experimental design.
• Analysis of phenolic compounds (acids and flavonoids) in the extract using High-Performance Liquid Chromatography with Photodiode Array/Mass Spectrometry (HPLC-PDA/MS).

Main Results:

• A choline chloride-malic acid (1:2 molar ratio)-based NADES demonstrated the highest total phenolic content.
• Optimal extraction conditions were determined: 1:21 solid-to-liquid ratio, 80°C, 43 minutes, and 29% added water.
• The optimized method yielded 9.51 ± 0.83 gallic acid equivalents per gram of BMRs.

Conclusions:

• Natural deep eutectic solvents offer a sustainable and efficient alternative for extracting phenolic compounds from barley malt rootlets.
• The optimized NADES extraction method provides a high yield of valuable antioxidants from an agri-food by-product.
• This research contributes to valorizing agri-food waste and promoting greener extraction technologies.