New glycerol glycosides in sake formed by Aspergillus oryzae α-glucosidase A
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View abstract on PubMed
Summary
This summary is machine-generated.Sake contains novel glycosides, including up to four glucose units linked to glycerol, identified using LC-MS and NMR. One major compound, alpha-isomaltosylglycerol (α-iMG), is prevalent in commercial sake.
Area Of Science
- Food Chemistry
- Biochemistry
- Enzymology
Background
- Sake production involves Aspergillus oryzae's alpha-glucosidase, which creates unique glycosides.
- These glycosides influence sake's flavor and may possess beneficial biological activities.
Purpose Of The Study
- To identify novel transglycosylation products in sake.
- To characterize the structure and prevalence of these newly identified compounds.
Main Methods
- Liquid chromatography-mass spectrometry (LC-MS) for detecting and identifying glycosides.
- In vitro transglycosylation experiments using recombinant alpha-glucosidase A (AgdA).
- Nuclear magnetic resonance (NMR) spectroscopy for structural elucidation.
Main Results
- Discovery of diglucopyranosylglycerol, triglucopyranosylglycerol, and tetraglucopyranosylglycerol in sake, representing the first observation of such long glucose chains.
- Absence of these compounds in sake brewed with AgdA-disrupted Aspergillus oryzae.
- Identification of alpha-isomaltosylglycerol (α-iMG) as a major in vitro synthesis product.
- Detection of α-iMG in commercial sake at an average concentration of 1095 ppm.
Conclusions
- The identified glycosides are transglycosylation products of glycerol and glucose units formed by Aspergillus oryzae's alpha-glucosidase.
- Alpha-isomaltosylglycerol (α-iMG) is a common component in commercial sake, marking its first reported occurrence in food and beverages.
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