AbstractThe influence of substitution of the (1 → 4)‐β‐D‐xylan backbone with α‐L‐arabinofuranosyl units on the infrared spectra has been studied using the freeze‐dried form of related oligo‐ and polysaccharide models. The peak intensity ratios at 1164 and 990 cm‐1 can be suggested as an index of arabinofuranosyl contribution. A valid correlation was found between the substitution of the xylosyl units at the position O‐3 by arabinosyl units and the intensity of the above‐mentioned absorption bands. The results are valuable for the identification of arabinoxylan type polysaccharides, as well as, for studies of the xylan component behaviour of plant materials in various technical and biotcch‐nological processes.