Abstract text: Accurate monosaccharide analysis of plant polysaccharides requires hydrolysis conditions that preserve labile neutral sugars and sensitive uronic acids. Classical approaches remain effective when combined with high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), but often rely on harsh conditions that degrade structural features. Ionic liquids (ILs) have emerged as powerful solvents capable of disrupting hydrogen-bond networks and enhancing accessibility of plant cell wall polysaccharides.

Here, we developed an IL-assisted workflow enabling both extraction and mild depolymerization while maintaining compatibility with HPAEC-PAD. De-starched and deproteinized faba bean cell wall material was treated with IL to extract intact polysaccharides, followed by mild acid hydrolysis within the same IL-enabled system. Compared to a conventional aqueous protocol, the IL-assisted method significantly increased arabinose recovery, reflecting preservation of arabinan-rich side chains of rhamnogalacturonan-I, which are typically degraded under acidic conditions, while maintaining uronic acid integrity.

Preliminary experiments with microcrystalline cellulose showed that IL treatment enhanced hydrolysis under reduced acid conditions, indicating improved accessibility of recalcitrant crystalline regions.

This approach improves monosaccharide recovery, preserves key structural features, and supports accurate analysis of complex plant cell wall polysaccharides.