Plant-Derived Polysaccharide Ultrafast Purification Reinvented: A Green Aqueous Two-Phase System with Deep Eutectic Solvents for Simultaneous Decolorization and Deproteinization

Abstract

Accurate characterization of plant-derived polysaccharides (PDPs) is often hindered by coextracted impurities such as proteins and pigments, which interfere with the elucidation of their chemical structures and functional properties. Conventional approaches for deproteinization and decolorization are typically time-consuming and environmentally unfriendly and may cause undesirable structural alterations in polysaccharides. Despite numerous attempts, no universally applicable method has yet been established to remove both classes of impurities. In this study, Lycium barbarum L. polysaccharides (LBPs) were employed as model polysaccharides to develop a deep eutectic solvent-based aqueous two-phase system (ATPS@DES) for the ultrafast purification of PDPs. Notably, the system enabled the concurrent deproteinization and decolorization of LBPs within only 10 s, achieving efficiencies greater than 94% while maintaining a polysaccharide retention above 77%. The pigment removal mechanism was elucidated through quantum chemical (QC) calculations. Subsequent physicochemical characterization and bioactivity assays confirmed that the purified polysaccharides retained their structural integrity and biological functions, thereby verifying the mildness and reliability of this process. Moreover, validation across 10 additional PDPs underscored the universality and applicability of the proposed method. Overall, ATPS@DES integrates ultrafast purification, high efficiency, and broad applicability into a green and reliable platform, providing a promising alternative to conventional multistep purification strategies for PDPs.