Comparative structural characterization of 7 commercial galacto-oligosaccharide (GOS) products. (29th April 2016)

• Record Type: Journal Article
• Authors: van Leeuwen, Sander S.; Kuipers, Bas J.H.; Dijkhuizen, Lubbert; Kamerling, Johannis P.
• Is Part Of: Carbohydrate research. Volume 425(2016)
• Page Start: 48
• Page End: 58
• Publication Date: 2016-04-29
• Subjects: Galacto-oligosaccharides -- NMR spectroscopy -- Prebiotics -- High-pH anion-exchange chromatography profiling; Carbohydrates -- Periodicals; Chemistry, Organic -- Periodicals; Biochemistry -- Periodicals; Carbohydrates -- Periodicals; Chimie organique -- Périodiques; Glucides -- Périodiques; Biochemistry; Carbohydrates; Chemistry, Organic; Periodicals; Electronic journals; 507.78
• DOI: 10.1016/j.carres.2016.03.006
• Languages: English
• ISSNs: 0008-6215

Abstract

Highlights: Seven GOS products were structurally characterized. Large structural diversity was observed between GOS preparations. 1D 1 H NMR and HPAEC-PAD profiling allow structural assessment of GOS. Structural-reporter-group library for GOS analysis was expanded. Graphical abstract: Abstract: Many β-galactosidase enzymes convert lactose into a mixture of galacto-oligosaccharides (GOS) when incubated under the right conditions. Recently, the composition of commercial Vivinal GOS produced by Bacillus circulans β-galactosidase was studied in much detail in another study by van Leeuwen et al. As a spin-off of this study, we used the developed analytical strategy for the evaluation of 6 anonymous commercial GOS products, in comparison with Vivinal GOS. These GOS products were first subjected to HPLC-SEC, calibrated HPAEC-PAD profiling (glucose units in relation to a malto-oligosaccharide ladder), and 1D 1 H NMR spectroscopy. For a more detailed analysis and support of the conclusions based on the initial analysis, the GOS products were separated into DP-pure subpools on Bio-Gel P-2 (MALDI-TOF-MS analysis), which were subjected to calibrated HPAEC-PAD profiling and 1 H NMR analysis. Unidentified peaks from different GOS products, not present in Vivinal GOS, were isolated for detailed structural characterization. In this way, the differences between the various GOS products in terms of DP distribution and type of glycosidic linkages were established. A total of 13 new GOS structures were characterized, adding structural-reporter-group signals and HPAEC-PAD based glucose unit G.U. values to the analytical toolbox. The newly characterized products enhance the quality of the database with GOS structures up to DP4. The combined data provide a firm basis for the rapid profiling of the GOS products of microbial β-galactosidase enzymes.