3-Deoxypentosulose:  An α-Dicarbonyl Compound Predominating in Nonenzymatic Browning of Oligosaccharides in Aqueous Solution

Abstract

The thermal degradation of D-glucose, maltose, and maltotriose in aqueous solution was investigated under caramelization (no glycine) and Maillard (with glycine) conditions. Degradation of the sugar and alpha-dicarbonyls product was monitored. Under both caramelization and Maillard reaction conditions, 3-deoxypentosulose was the predominating alpha-dicarbonyl compound formed from maltose and maltotriose. In the absence of an amino compound, however, 3-deoxypentosulose is formed in much lower concentration. It was concluded that 3-deoxypentosulose is formed by a pathway specific for oligo- and polysaccharides since this alpha-dicarbonyl is formed from the alpha-1-->4 glucans such as maltose and maltotriose but not from glucose. For its formation, a retro Claisen reaction of an enolization product of 1-amino-1,4-dideoxyhexosulose is proposed as the route to its formation. 1-Amino-1,4-dideoxyhexosulose could be formed by vinylogous alpha-elimination from the 2,3-enediol structure after Amadori rearrangement, favored by planar alignment of the bonds between C1 and C4. Subsequent rearrangement by keto-enoltautomerization leads to a 1-imino-3-keto structure. In this structure, attack of a hydroxyl anion, provided by water at neutral pH, could cause a splitting off of the C1. This reaction gives rise to formic acid or formamide and a pentose derivative, which reacts further to give 3-deoxypentosulose.

Quantification of the Maillard reaction product 6-(2-formyl-1-pyrrolyl)-l-norleucine (formyline) in food

“…In these foods, the precursor 3-deoxypentosone can form during degradation reactions of starch and oligosaccharides, especially in the presence of water [31,32]. Under quasi water-free conditions, 1,4-dideoxyhexosulose is cleaved from oligosaccharides and possibly starch in the presence of amines [31].…”

Occurrence of acetic acid and formic acid in breakfast cereals

“…AA formation is favoured as a consequence of the lower reactivity of sucrose and the already high presence of monosaccharides in breakfast cereals, mainly from thermal and Maillard-mediated hydrolysis of disaccharides. 21 Statistically significant differences in the FA content were found between cereals based on wheat and corn flours and those based on rice or the mixed cereals (Table 5).…”

Effects of pH on the Formation of Volatile Products in Non-Enzymatic Browning of Maltose

“…The present results showed that the pathway involving 3-deoxypentulose might be one of the main routes for maltose degradation at pH 7-8. Hollnagel and Kroh (2002) reported that 3-deoxypentosulose is the predominant ␣-dicarbonyl compound specifically formed from 1,4-linked oligosaccharides, i.e. maltose and maltotriose, under both caramelization and Maillard reaction conditions.…”