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Published on: April 13, 2019
Characterization of galactooligosaccharides derived from lactulose
Oswaldo Hernández-Hernández1, Fernando Montañés, Alfonso Clemente
1Instituto de Química Orgánica General (CSIC) C/Juan de la Cierva 3, 28006 Madrid, Spain.
Journal of Chromatography. A
|June 7, 2011
Summary
This study characterizes galactooligosaccharides (GOS) produced from lactulose using fungal enzymes. Different enzymes yield GOS with varying degrees of polymerization, impacting their potential as prebiotics.
Area of Science:
- Microbiology
- Carbohydrate Chemistry
- Biotechnology
Background:
- Galactooligosaccharides (GOS) are non-digestible carbohydrates with prebiotic potential.
- Modulating the intestinal microbiota is crucial for gut health.
- Enzymatic synthesis offers a route to produce specific oligosaccharide structures.
Purpose of the Study:
- To characterize oligosaccharides produced by transgalactosylation of lactulose using different fungal β-galactosidases.
- To compare the degree of polymerization (DP) and structures of GOS synthesized by Aspergillus oryzae, Aspergillus aculeatus, and Kluveromyces lactis enzymes.
- To identify byproducts formed during the enzymatic synthesis.
Main Methods:
- Transgalactosylation reactions using lactulose as a substrate and β-galactosidases from A. oryzae, A. aculeatus, and K. lactis.
- High-Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry (HPLC-ESI-MS) for detecting and quantifying oligosaccharides up to DP6.
- Gas Chromatography-Mass Spectrometry (GC-MS) analysis of trimethylsilyl oximes for characterizing disaccharides and trisaccharides.
Main Results:
- Oligosaccharides up to DP6 were detected using A. oryzae enzymes (GOSLuAo).
- Enzymes from K. lactis (GOSLuKl) and A. aculeatus (GOSLuAa) produced oligosaccharides up to DP4 and DP5, respectively.
- Disaccharides (galactosyl-galactoses, galactosyl-fructoses) and trisaccharides were identified in all mixtures.
- Galactosyl- and digalactosyl-glycerols were formed when glycerol was present as a stabilizer with A. aculeatus and K. lactis enzymes.
Conclusions:
- The choice of β-galactosidase significantly influences the yield and DP of GOS produced from lactulose.
- HPLC-ESI-MS and GC-MS are effective methods for characterizing complex GOS mixtures.
- Understanding GOS structure is key to optimizing their prebiotic effects and potential applications in functional foods.
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