Optimization of the extraction and purification of oligosaccharides from defatted soybean meal

Summary Optimization of the extraction of oligosaccharides from defatted soybean meal (DSM) was investigated under various conditions. The optimal ratio of water to DSM and optimal temperature for oligosaccharide extraction was 5:1 and 50 °C, respectively. The use of a stirring process, without any further grinding, improved the extractability of oligosaccharides from DSM, a 10% ethanol‐water solution was more effective than distilled water alone. To purify the oligosaccharides, ultrafiltration was used. More than 90% of the protein was removed from the extracts at a volume concentration ratio (VCR) of 3–5. The percentages of fructose, sucrose, raffinose and stachyose in permeate for a VCR of 5 were 38.6, 51.4, 54.2 and 52.6%, respectively. A VCR of 5 was the most effective for protein removal and recovery of oligosaccharides.