Revisiting the structural features of arabinoxylans from brewers' spent grain

- In Brewers' spent grain (BSG) arabinose did not justify all branches present in xylan.
- Mass spectrometry (MS) analysis assigned other substituents than arabinose on xylan.
- MS analysis revealed also hexose residues attached to arabinoxylans.
- BSG presents glucuronoarabinoxylans and acetylated arabinoxylans.
- The BSG is a potential source of a large screening prebiotic by-product.