Use of a deep eutectic solvent-assisted matrix solid-phase dispersion extraction for phenolic compounds determination from pigmented wheat

In this study, an innovative extraction method for the determination of phenolic compounds in pigmented wheat was developed and optimized. Using deep eutectic solvents (DESs), a greener alternative extraction procedure is offered to the conventional ones based on organic solvents. A matrix solid-phase dispersion (MSPD) extraction was performed and enhanced by the addition of DES in the homogenization step. In comparison with an ultrasound-assisted solid liquid extraction, the MSPD-DES technique allowed to obtain a higher extraction efficiency reducing organic solvent consumption and environmental impact. Although different DESs were tested, the one based on choline chloride and glycerol (1:2 molar ratio) showed the best extraction yield of phenolic compounds. A three-level four-factor Box-Behnken design optimization was performed: sample-to-dispersing material ratio, DES volume, extraction solvent volume, and number of cycles were evaluated. Under the optimal conditions a total phenolic content (TPC) of 3.562 ± 0.005 mg GAE/g was achieved. The AGREEprep, BAGI, and ComplexMoGAPI indicators confirmed the environmental sustainability of the proposed methodology. The qualitative profile of the extracted phenolic compounds was determined using high-performance liquid chromatography-photodiode array detector.