A major challenge in isolating oligosaccharides from dairy streams is to enrich oligosaccharides while simultaneously reducing the content of simple sugars (mono- and disaccharides) that do not possess the desired prebiotic functions. An integrated approach based on optimized conditions that favor maximum lactose hydrolysis, monosaccharide fermentation and oligosaccharides recovery by nanofiltration was developed. Upon complete lactose hydrolysis and fermentation of the monosaccharides by yeast, nanofiltration of fermented whey permeate from colostrum enabled the recovery of 95% of the oligosaccharides at high purity. While the number of commercially available standards has limited the quantification of only a few sialylated oligosaccharides, the application of both high performance anion exchange chromatography with pulsed amperometric detection and mass spectrometry provided a complete profile of the final product. Approximately 85% of the oligosaccharides in the final concentrate were sialylated, with the remainder being neutral. (C) 2017 Elsevier Ltd. All rights reserved.