Recycling of wheat gluten wastewater: separation, characterisation, and solution rheology of arabinoxylans

A significant volume of gluten production wastewater, containing arabinoxylan, is generated during wheat processing, presenting an underutilised resource. In this study, water-extractable arabinoxylan (WEAX) was obtained from this wastewater through water extraction and alcohol precipitation, followed by purification, and its chemical and rheological properties were subsequently investigated. The analysis revealed a mean molecular weight of 4.57 x 104 Da for WEAX, with arabinose (38.08%) and xylose (43.77%) as the predominant monosaccharides. Notably, the sample exhibited characteristic structural properties of arabinoxylan, as confirmed by FT-IR spectra. Scanning electron microscopy further revealed a heterogeneous solid morphology, comprising filamentous flake and spherical structures. Moreover, WEAX demonstrated favourable thermal stability and revealed shear-thinning behaviour, as well as weak gelation, as evidenced by thermogravimetry, differential scanning calorimetry, and rheological analysis. This study not only presents a novel approach for the resource treatment of wheat gluten production wastewater but also contributes new insights into the characterisation of arabinoxylan. Recycling of wastewater from gluten production: extraction of arabinoxylan. Arabinoxylan was purified by static adsorption of cellulose DE52. The main monosaccharides of arabinoxylan were arabinose (38.08%) and xylose (43.77%). Arabinoxylan exhibits pseudoplastic fluid behaviour with shear thinning and weak gelation.image