Sugar Fragmentation in the Maillard Reaction Cascade: Isotope Labeling Studies on the Formation of Acetic Acid by a Hydrolytic 
der="0" align
der="0" align
详细信息 查看全文
- 作者：Tomas Daví ; dek ; Sté ; phanie Devaud ; Fabien Robert ; Imre Blank
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2006
- 出版时间：September 6, 2006
- 年：2006
- 卷：54
- 期：18
- 页码：6667 - 6676
- 全文大小：173K
- 年卷期：v.54,no.18(September 6, 2006)
- ISSN：1520-5118
文摘
The formation of acetic acid was elucidated based on volatile reaction products and related nonvolatilekey intermediates. The origin and yield of acetic acid were determined under well-controlled conditions(90-120 
deg.gif">C, pH 6-8). Experiments with various 13C-labeled glucose isotopomers in the presence ofglycine revealed all six carbon atoms being incorporated into acetic acid: C-1/C-2 (~70%), C-3/C-4(~10%), and C-5/C-6 (~20%). Acetic acid is a good marker of the 2,3-enolization pathway since itis almost exclusively formed from 1-deoxy-2,3-diulose intermediates. Depending on the pH, the aceticacid conversion yield reached 85 mol % when using 1-deoxy-2,3-hexodiulose (1) as a precursor.Hydrolytic 
ddle">-dicarbonyl cleavage of 1-deoxy-2,4-hexodiuloses was shown to be the major pathwayleading to acetic acid from glucose without the intermediacy of any oxidizing agents. The presenceof key intermediates was corroborated for the first time, i.e., tetroses and 2-hydroxy-3-oxobutanal, atautomer of 1-hydroxy-2,3-butanedione, also referred to as 1-deoxy-2,3-tetrodiulose. The hydrolyticddle">-dicarbonyl cleavage represents a general pathway to organic acids, which corresponds to an acyloincleavage or a retro-Claisen type reaction. Although alternative mechanisms must exist, the frequentlyreported hydrolytic 
-dicarbonyl cleavage of 1 can be ruled out as a pathway forming carboxylicacids.
deg.gif">C, pH 6-8). Experiments with various 13C-labeled glucose isotopomers in the presence ofglycine revealed all six carbon atoms being incorporated into acetic acid: C-1/C-2 (~70%), C-3/C-4(~10%), and C-5/C-6 (~20%). Acetic acid is a good marker of the 2,3-enolization pathway since itis almost exclusively formed from 1-deoxy-2,3-diulose intermediates. Depending on the pH, the aceticacid conversion yield reached 85 mol % when using 1-deoxy-2,3-hexodiulose (1) as a precursor.Hydrolytic ddle">-dicarbonyl cleavage of 1-deoxy-2,4-hexodiuloses was shown to be the major pathwayleading to acetic acid from glucose without the intermediacy of any oxidizing agents. The presenceof key intermediates was corroborated for the first time, i.e., tetroses and 2-hydroxy-3-oxobutanal, atautomer of 1-hydroxy-2,3-butanedione, also referred to as 1-deoxy-2,3-tetrodiulose. The hydrolyticddle">-dicarbonyl cleavage represents a general pathway to organic acids, which corresponds to an acyloincleavage or a retro-Claisen type reaction. Although alternative mechanisms must exist, the frequentlyreported hydrolytic -dicarbonyl cleavage of 1 can be ruled out as a pathway forming carboxylicacids.