Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/12/2019
Publication Date: 5/5/2019
Citation: Liu, K. 2019. Aqueous extraction for making feed proteins from soybeans. Annual Meeting and Expo of the American Oil Chemists' Society. PCP 4a.
Technical Abstract: Defatted soymeal, a coproduct of modern soybean processing, is primarily used in feed for various livestock and farm fish worldwide. Because the defatting process uses hexane, it suffers from safety concerns and negative environmental impact and fails to remove heat-stable antinutrients directly. Thus, research was conducted to develop soy protein ingredients with reduced heat-stable antinutrients using aqueous solvents instead of hexane. Raw soybeans were divided into two portions, one was ground into enzyme active flour and the other was oven-roasted and ground into roasted flour. Aqueous extraction was done using both concentrate and isolate approaches. The effect of the aqueous extraction on content and recovery rate of protein, oil, oligosaccharides, and phytate in resulting protein products were investigated. The concentrate approach was applicable to both enzyme-active and roasted flours. Protein concentrates produced had oligosaccharides and phytate contents significantly lower than the original flours (85-92% and 56-74% reduction, respectively). The isolate approach was applicable only to the enzyme-active flour. The resulting isolate had higher protein content, but lower protein recovery than the concentrate. Both products had similar oligosaccharide contents, but the isolate had phytate content even higher than the raw flour. With either approach, oil was not easily separated out. Instead it went either into the protein fraction using the concentrate approach or into the fiber and protein fractions using the isolate approach. Based on the composition and recovery of nutrients and antinutrients, the protein concentrate made by the aqueous process was suitable for feed application.