The interaction of lignin and hemicellulose in the lignocellulosic matrix creates a recalcitrant cell wall that limits the efficacy and viability of lignocellulosic biorefinery. Biorefinery uses integrated processes involving pre-treatment, fractionation, separation and purification to convert biomass into individual constituents, which are transformed into high-value chemicals, fuel, materials and energy. In cereals such as barley and its major byproduct from the brewing industry (brewer’s spent grains (BSG)), lignin and the hemicellulose domain, predominated by arabinoxylans, are crosslinked by hydroxycinnamic acid, mainly ferulic acid to form a rigid cell wall. Here, we report the use of selective deep eutectic solvents (DES) based on choline chloride and different carboxylic acids to preserve ferulic acid acyl groups on C-OH of α-l-arabinosyl moieties of arabinoxylans, enabling a selective cell wall deconstruction. As a result, a wide range of bioactive components with health-promoting biological activities initially inaccessible because they are bound within the cell wall are recovered and identified. Our preliminary results from MS1 scans in negative ion mode using a drift tube ion mobility-mass spectrometry confirmed more than 10 theoretical m/z values resulting from BSG cell wall deconstruction. These ions were confirmed to result from the release of feruloylated arabinoxylo-oligosaccharides (FAAO) with varying degrees of glycosylation. By tracking acetyl substitutions on xylosyl residues of released FAAOs, it is expected that more FAAOs could be identified. These preliminary data warrant further fragmentation experiments and the computation of collision cross-sections to accurately resolve the structures of major compounds from the cell wall deconstruction. The implications of these results are three-fold: