Green extraction of xylan hemicellulose from wheat straw

Hemicellulose, as a rich source of five distinct sugars, has a wide range of application prospects. The physicochemical properties of hemicellulose depend on the source and extraction method. The aim of this study was to determine the effect of hydrothermal severity on the chemical composition, extraction yield, and purity of hemicellulose. Hence, wheat straw was subjected to hydrothermal process using an experimental design with 16 runs: 140–170 °C reaction temperatures, 30—120-min reaction time, and liquor to solid ratio of 15. The pre-extracted wheat straw showed higher thermal stability compared to the untreated wheat straw. The presence of hemicelluloses in the pre-extracted wheat straw as well as recondensation of lignin over the pre-extraction stage was suggested based on the FT-IR data. The xylose content (62.35–68.13%) and lignin content (4.14–9.02%) of hemicellulose increased along with heightening the severity factor from 2.34 to 3.18. The data showed that using hydrothermal process with SF of 2.34–3.18 is an efficient method to isolate high purity hemicellulose (91–96%) including β-(1→4)-D-xylopyranosyl residues and side branches of a-L-arabinofuranosyl groups from wheat straw with possible application in developing sweeteners and thickening agents for a wide range of industrial applications such as bakery products, beverages, and pharmaceutical syrups. Graphical abstract