Green Chemistry and Multivariate Optimization in the Extraction of Phenolic Compounds: The Potential of NaDES in Alternative Raw Materials for Expanded Extrudates.

Abstract

Phenolic compounds are secondary metabolites widely distributed among plants, with bioactive properties, especially antioxidant activity. The search for sustainable extraction methods has driven the use of natural deep eutectic solvents (NaDESs), formed by combinations of natural compounds, such as organic acids, sugars, alcohols, and amino acids. This study optimized NaDES (sorbitol, citric acid, and glycine) efficiency and compared it to that of 70% methanol solution in extracting total soluble phenolic compounds (TSPCs) from six flours matrices-corn, buckwheat, biofortified orange sweet potato, red lentil, Sudan grass, and chickpea-before and after thermoplastic extrusion cooking. Quantification was performed using the Folin-Ciocalteu method, with statistical analysis at the 10% significance level. In general, the methanolic extracts showed higher TSPC levels in the raw materials, whereas the levels were higher in NaDESs for legumes. After extrusion, a reduction in the TSPC levels was observed, except in the sweet potato. Multivariate analysis (PLS-DA and heatmap) distinguished the raw and extruded samples, revealing structural and chemical changes from thermal processing. The AGREE scores were 0.7 (NaDES) and 0.54 (methanol), favoring NaDES. The BAGI score (75.0) confirmed the method's robustness and suitability for sustainable analytical applications.