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TAUTOMERIC EQUILIBRIA OF D‐GLUCOSE AND D‐FRUCTOSE: NMR SPECTROMETRIC MEASUREMENTS
Author(s) -
HYVÖNEN LEA,
VARO PERTTI,
KOIVISTOINEN PEKKA
Publication year - 1977
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1977.tb12572.x
Subject(s) - tautomer , anomer , chemistry , fructose , equilibrium constant , anomeric effect , analytical chemistry (journal) , mass spectrometry , chromatography , organic chemistry
The influence of temperature and concentration on the anomeric equilibrium of glucose was determined by 1 H NMR spectrometry and on the tautomeric equilibrium of fructose by 1 3 C Fourier transformation NMR spectrometry. The proportion of the ol‐anomer at the equilibria of glucose solutions was approximately constant at 5% and 10% concentrations at different temperatures. At higher concentrations (20, 50 and 65%) the proportion of the cy‐anomer at equilibrium was increased at higher temperatures. The proportion of both α‐ and β‐fructofuranoses was increased at the equilibrium of 20% fructose solutions at higher temperatures. The tautomeric equilibrium of fructose remained approximately unchanged in the 20, 50 and 80% fructose solutions at room temperature.