In-Depth Mechanistic Study on the Formation of Acrylamide and Other Vinylogous Compounds by the Maillard Reaction
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- 作者：Richard H. Stadler ; Fabien Robert ; Sonja Riediker ; Natalia Varga ; Tomas Davidek ; Sté ; phanie Devaud ; Till Goldmann ; Jö ; rg Hau ; and Imre Blank
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2004
- 出版时间：August 25, 2004
- 年：2004
- 卷：52
- 期：17
- 页码：5550 - 5558
- 全文大小：160K
- 年卷期：v.52,no.17(August 25, 2004)
- ISSN：1520-5118
文摘
The formation of acrylamide was studied in low-moisture Maillard model systems (180 
f">C, 5 min)based on asparagine, reducing sugars, Maillard intermediates, and sugar degradation products. Weshow evidence that certain glycoconjugates play a major role in acrylamide formation. The N-glycosylof asparagine generated about 2.4 mmol/mol acrylamide, compared to 0.1-0.2 mmol/mol obtainedwith 
fchars/alpha.gif" BORDER=0>-dicarbonyls and the Amadori compound of asparagine. 3-Hydroxypropanamide, the Streckeralcohol of asparagine, generated only low amounts of acrylamide (~0.23 mmol/mol), whilehydroxyacetone increased the acrylamide yields to more than 4 mmol/mol, indicating that fchars/alpha.gif" BORDER=0>-hydroxycarbonyls are much more efficient than fchars/alpha.gif" BORDER=0>-dicarbonyls in converting asparagine into acrylamide. Theexperimental results are consistent with the reaction mechanism based on (i) a Strecker typedegradation of the Schiff base leading to azomethine ylides, followed by (ii) a fchars/beta2.gif" BORDER=0 ALIGN="middle">-elimination reactionof the decarboxylated Amadori compound to afford acrylamide. The fchars/beta2.gif" BORDER=0 ALIGN="middle">-position on both sides of thenitrogen atom is crucial. Rearrangement of the azomethine ylide to the decarboxylated Amadoricompound is the key step, which is favored if the carbonyl moiety contains a hydroxyl group infchars/beta2.gif" BORDER=0 ALIGN="middle">-position to the nitrogen atom. The fchars/beta2.gif" BORDER=0 ALIGN="middle">-elimination step in the amino acid moiety was demonstratedby reacting under low moisture conditions decarboxylated model Amadori compounds obtained bysynthesis. The corresponding vinylogous compounds were only generated if a fchars/beta2.gif" BORDER=0 ALIGN="middle">-proton was available,for example, styrene from the decarboxylated Amadori compound of phenylalanine. Therefore, it issuggested that this thermal pathway may be common to other amino acids, resulting under certainconditions in their respective vinylogous reaction products.Keywords: Acrylamide; asparagine; Maillard reaction; mechanisms; synthesis; Strecker degradation;fchars/beta2.gif" BORDER=0 ALIGN="middle">-elimination; decarboxylated Maillard intermediates; azomethine ylides; LC-MS/MS; GC-MS; NMR.
f">C, 5 min)based on asparagine, reducing sugars, Maillard intermediates, and sugar degradation products. Weshow evidence that certain glycoconjugates play a major role in acrylamide formation. The N-glycosylof asparagine generated about 2.4 mmol/mol acrylamide, compared to 0.1-0.2 mmol/mol obtainedwith fchars/alpha.gif" BORDER=0>-dicarbonyls and the Amadori compound of asparagine. 3-Hydroxypropanamide, the Streckeralcohol of asparagine, generated only low amounts of acrylamide (~0.23 mmol/mol), whilehydroxyacetone increased the acrylamide yields to more than 4 mmol/mol, indicating that fchars/alpha.gif" BORDER=0>-hydroxycarbonyls are much more efficient than fchars/alpha.gif" BORDER=0>-dicarbonyls in converting asparagine into acrylamide. Theexperimental results are consistent with the reaction mechanism based on (i) a Strecker typedegradation of the Schiff base leading to azomethine ylides, followed by (ii) a fchars/beta2.gif" BORDER=0 ALIGN="middle">-elimination reactionof the decarboxylated Amadori compound to afford acrylamide. The fchars/beta2.gif" BORDER=0 ALIGN="middle">-position on both sides of thenitrogen atom is crucial. Rearrangement of the azomethine ylide to the decarboxylated Amadoricompound is the key step, which is favored if the carbonyl moiety contains a hydroxyl group infchars/beta2.gif" BORDER=0 ALIGN="middle">-position to the nitrogen atom. The fchars/beta2.gif" BORDER=0 ALIGN="middle">-elimination step in the amino acid moiety was demonstratedby reacting under low moisture conditions decarboxylated model Amadori compounds obtained bysynthesis. The corresponding vinylogous compounds were only generated if a fchars/beta2.gif" BORDER=0 ALIGN="middle">-proton was available,for example, styrene from the decarboxylated Amadori compound of phenylalanine. Therefore, it issuggested that this thermal pathway may be common to other amino acids, resulting under certainconditions in their respective vinylogous reaction products.Keywords: Acrylamide; asparagine; Maillard reaction; mechanisms; synthesis; Strecker degradation;fchars/beta2.gif" BORDER=0 ALIGN="middle">-elimination; decarboxylated Maillard intermediates; azomethine ylides; LC-MS/MS; GC-MS; NMR.