Unit operations to enhance protein extraction within the food industry are vital to improve current processes, especially for cost reductions and sustainability. Here a study of ultrasound-assisted extraction (UAE) from soy slurry and okara produced at pilot-scale and further processed using a lab or pilot-scale probe system is presented. Confocal imaging and particle size measurements were used to study the physical effects of UAE on these soy processing materials. Ultrasound at pilot-scale was infeasible for soy slurry, in contrast to lab-scale. UAE from okara solution significantly increased protein yield by 4.2% at pilot-scale (p < 0.05). Okara solution flow rate and okara concentration also significantly improved the protein extraction yield. During lab-scale sonication of okara solution, a greater energy intensity resulted in a higher yield of up to 40% after 15 min treatment. Considering total extraction yields at pilot-scale during soybase production, ultrasound is not considered viable for industrial processing. (C) 2017 The Authors. Published by Elsevier Ltd.