Origin of 2,3-pentanedione and 2,3-butanedione in D-glucose/L-alanine Maillard model systems.
Model studies using independently labeled D-[(13)C]glucoses and L-[(13)C]alanines have indicated that 2,3-butanedione is formed by a single pathway involving only glucose carbon atoms, whereas 2, 3-pentanedione is formed by two pathways, one involving glucose carbon atoms (10%) and the other (90%) through the participation of C2'-C3' atoms of L-alanine and a C(3) carbon unit from D-glucose. Analysis of label incorporation into selected mass spectral fragments of 2,3-pentanedione have indicated that the C(3) carbon unit originates either from C1-C2-C3 or from C4-C5-C6 fragments of D-glucose. In addition, model studies with pyruvaldehyde and glyceraldehyde have implicated these intermediates as plausible C(3) glucose carbon units capable of producing 2,3-pentanedione upon reaction with L-alanine. The labeling studies have also confirmed a previously identified chemical transformation of alpha-keto aldehydes affected by the amino acid that leads to the addition of the C-2 atom of the amino acid to the aldehydic carbon atom of alpha-keto aldehydes.
Yaylayan
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VA
McGill University, Department of Food Science and Agricultural Chemistry, Quebec, Canada.
Keyhani
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A
D000409:Alanine / Q000737:chemistry*; D002247:Carbon Isotopes; D003931:Diacetyl / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D005947:Glucose / Q000737:chemistry*; D015416:Maillard Reaction; D008956:Models, Chemical; D010422:Pentanones / Q000737:chemistry*
D002247:Carbon Isotopes; D010422:Pentanones; D005947:Glucose; D003931:Diacetyl; C013186:2,3-pentanedione; D000409:Alanine