Improved efficiency of brewer’s spent grain arabinoxylans by ultrasound-assisted extraction

•Significant reduction of extraction time using ultrasound assisted extraction.•Less energy and solvent consumption using ultrasound assisted extraction.•Arabinoxylans rich extracts obtained with ultrasound almost absent of starch.•Ultrasound assisted extraction produced smaller arabinoxylans polymers.

Arabinoxylan (AX) rich extracts from brewer’s spent grain (BSG) were produced by the application of ultrasound-assisted extraction (UAE) and conventional alkaline extraction (AKE). UAE and AKE were optimised for the production of the highest yield of ethanol insoluble material using response surface methodology (RSM). The efficiency of UAE was established by the significant reduction of time (7 h to 25 min) and energy when compared to AKE, to recover similar amounts of AX (60%) from BSG, leading to the production of starch-free AX-rich extracts.