A Pilot‐Plant Study of Continuous Ultrasonic Extraction of Soybean Protein

Abstract

Methods were studied to extract soybean proteins from commercial defatted flakes with ultrasonic energy, continuously and efficiently, in a pilot plant. Studies also included batchwise sonication of aqueous soybean slurries in a tank. Parameters investigated included soybean‐to‐solvent ratios of 1:10, 1:20, and 1:30; solvents of tap water and 0.1N NaOH; and extraction with and without sonication. Protein yield and energy requirements for extraction were measured to correlate the operating condition with the extent of protein extraction. For a residence time of 0.7 sec in the continuous sonication process, the extracted protein yield was greatest at 1:30 soy‐to‐alkaline solvent ratio. Energy input to produce protein isolate is the least at 1:10 soy‐to‐alkaline solvent. Although the continuous sonication procedure is workable, the commercial operation remains to be tested.