Scientific journal NRU ITMO
Series "Processes and Food Production Equipment"
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ISSN:2310-1164

September 2019 (published: 24.09.2019)

Number 3(41)

Home > Issue > Synthesis, structure, and formation mechanisms of D-mannose alkali-catalyzed thermodestruction products in aqueous-ethanolic media

UDC 664.11:543.21

Synthesis, structure, and formation mechanisms of D-mannose alkali-catalyzed thermodestruction products in aqueous-ethanolic media

Cherepanov I.S.

Carbohydrate raw materials is an important and available source of potentially biologically active ecologically pure products. Being diastereomers with similar general properties simple monosaccharides show specific activity in processes of live and industrial technological systems, which call in studying transformation processes and products structure for each carbohydrate whereas available research data concern generally D-glucose reactions. Alkali-catalyzed reactions of D-mannose in mixed aqueous-ethanolic media are studied by UV-Vis and vibrational spectroscopy with the use of thin layer chromatography and elemental analysis data. The active dynamics of reaction by the time of 30 min from the beginning of interaction registered by monitoring optical density values of solutions at the wavelength of 420 nanometers is shown. Chromatograms of processes registered at 30, 60, and 90 min also show existence of low and high-molecular thermodestruction products. Processes under investigation proceed under moderate in comparison with dry caramelization temperature conditions (800C) due to the use of mixed aqueous-alcoholic solvent. The latter reduces quantity of low-molecular volatile products allowing to explore the structure of solid products in detail. Detailed studying of IR-Fourier transform spectra and their second derivatives of the solid products isolated from reactionary systems shows existence the carbohydrate rings (bands at 800–1000 and 1140–1175 cm-1) and unsaturated functions, in particular C=C, C=O, COOH (bands at 1600–1750 cm-1), as basic structural elements. Based on data obtained the main processes of thermodestruction product structure formation in the system in question it is assumed oxidizing cleavage of carbohydrate enolic forms together with α-dicarbonyl derivatives’ formation with their subsequent aldol-type condensation, glycosylation processes influencing at the later stages. Thermodestrucion products’ heterofunctionality is responsible for their natural color properties, antibacterial, and reductive activity.
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Keywords: chemical analysis methods; D-mannose; IR-Fourier transform spectroscopy; aqueous-ethanolic media; thermodestruction; product structure

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