Natural deep eutectic solvents for stilbenoid extraction from vine by-products: Solubilization and extraction...

Area of Science:

• Green Chemistry
• Analytical Chemistry
• Natural Product Chemistry

Background:

• Natural deep eutectic solvents (NADES) are sustainable alternatives for polyphenol extraction.
• Selecting optimal NADES is challenging due to numerous combinations and lack of rapid screening methods.
• Efficient extraction of stilbenoids like resveratrol from plant sources is of significant interest.

Purpose of the Study:

• Develop a rapid, cost-effective UV-Vis screening method for assessing stilbenoid solubility in NADES.
• Establish a standard-free approach for NADES selection in polyphenol extraction.
• Optimize NADES-assisted extraction of stilbenoids from grape cane.

Main Methods:

• Screened 20 NADES using a UV-Vis method on a stilbenoid-rich plant extract.
• Correlated UV-Vis results with HPLC-DAD analysis (r = 0.49-0.61) for preselection.
• Optimized extraction parameters (solid-to-liquid ratio, time, water content) using Box-Behnken design and ultrasound-assisted extraction.

Main Results:

• Identified betaine/levulinic acid (1:2 molar ratio) as the most efficient NADES.
• Determined optimal extraction conditions: 20 min, 39% water content, and specific solid-to-liquid ratio.
• Achieved high yields of (E)-resveratrol (2.6 g kg⁻¹) and (E)-ε-viniferin (2.5 g kg⁻¹) from recent Cabernet Sauvignon cane samples.

Conclusions:

• UV-Vis based screening is a rapid, scalable, and standard-free strategy for NADES selection.
• This method facilitates efficient and sustainable NADES-assisted extraction processes.
• The optimized NADES extraction method is comparable to conventional systems and effective for diverse plant materials.