The purpose of this article is to study molecular dynamics through nuclear magnetic relaxation (NMR) dispersion of Arabic gum aqueous solutions analysed in terms of two-fraction exchange model. The experiments revealed that relaxation of water molecules was non-monoexponential, which was interpreted in terms of a model describing the magnetization transfer due to exchange of water and polysaccharide protons. The analysis showed that water dynamics decreased slightly with gum content. Polymer-chain dynamics was assigned to regime II of the tube/reptation model. Peculiar temperature dependence of exchange rate was observed in the whole concentration range of Arabic gum solutions. NMR relaxation probed in a broad frequency and temperature range allows probing of the molecular dynamics of complex food systems. © 2022 Society of Chemical Industry.