Separation of saponins from quinoa bran by a novel single-column three-stage foam fractionation technology

This study developed a novel single-column three-stage foam fractionation technology to separate saponins from quinoa bran. For efficient separating saponins from their highly concentrated aqueous solution (300 mg/L), large bubbles, multi-layered foam and small bubbles performed their own specific functions to achieve a high enrichment ratio of 7.1 and a high recovery percentage of 91.7%, respectively. Multi-layered foam could strengthen the foam drainage with a low liquid holdup of 0.5% and enhance the foam stability with a high half-life of 630 s simultaneously. FTIR and HPLC-MS were performed to analyze and characterize the ingredients of the product (mainly are triterpenoid saponins) and the purity of total saponins (91.9%). This work is expected to provide a simple and highly-efficient technology for the separation of natural surface-active substances and facilitate the industrial application of foam fractionation.