Comparative Recalcitrance and Extractability of Cell Wall Polysaccharides from Cereal (Wheat, Rye, and Barley) Brans Using Subcritical Water

Cereal brans constitute an unexploited source of valuable cell wall polysaccharides and phenolics. Sequential subcritical water extraction (SWE) of wheat, barley, and rye bran enables the isolation of cell wall polysaccharides with targeted molecular structures. The extracts switched from glucan-rich to higher contents of feruloylated arabinoxylan (F-AX) with extraction time, resulting in significant radical scavenging activity. Structurally, wheat and rye F-AXs exhibited mostly single C­(O)-3 arabinose substitutions, whereas barley bran F-AX showed a complex substitution pattern. The recalcitrance of the insoluble residues after SWE was revealed by the enrichment of F-AX populations with disubstituted arabinose units and the presence of hydroxycinnamic acids, lignin, and proteins. This study demonstrates the versatility of SWE to extract cell wall polysaccharides from cereal brans with tailored molecular structures and radical scavenging activity for potential use in food and biomedical applications.