Biopurification of functional soybean oligosaccharides from defatted soybean yellow pulp water fermented by yeast species: A process study.

This study presents a biotechnological method for isolating highly functional soybean oligosaccharides (SBOS) from soybean yellow pulp water (YPW) using microbial fermentation and resin-based purification methods. Candida sake selectively metabolizes sucrose, enabling the enrichment of target oligosaccharides. Under optimized fermentation conditions (6 % w/v YPW, 4 % v/v inoculum, and 28 °C), an 8 h process achieved retention rates of 85.93 % for raffinose and 85.17 % for stachyose, preserving the functional oligosaccharides. Isoelectric precipitation at pH 4.6 removed 72.47 % of the protein, while sequential treatment with AB-8, 001 × 7, and D392 resins resulted in 72.47 % decolorization and 74.98 % desalination at a flow rate of 2 BV/h. The final product contained 74.98 % functional oligosaccharides, demonstrating the scalability of the proposed approach for YPW valorization. These findings contribute to the sustainable utilization of soybean-processing byproducts through targeted resource recovery strategies.