Use of o-phthalaldehyde derivatives and high-pressure liquid chromatography in determining the free amino acids in cocoa beans

Wj, Hurst; Ra, Martin

doi:10.1021/jf60231a044

Cited by 9 publications

(1 citation statement)

References 2 publications

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“…Therefore, the formation of corresponding vinylogous compounds in foods is not clear-cut (see Figure 1) and must be studied on a case-by-case basis, taking into account the availability of free amino acids and sugars in the raw agricultural commodity and thermal-processing conditions. Gln and Glu are abundant amino acids present in a free form in many different foods such as wheat (26,27), soybean (28), almonds (28), cocoa (29), and coffee (30). Hence, the Maillard reaction may contribute significantly to the formation of 2-Pyr levels in cooked and roasted foods.…”

Section: Discussionmentioning

confidence: 99%

Formation of Vinylogous Compounds in Model Maillard Reaction Systems

Stadler

Verzegnassi

Varga

et al. 2003

Chem. Res. Toxicol.

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The thermal degradation over temperature and time of selected amino acids (Asp, Gln, and Glu) in the presence of reducing sugars was investigated in low moisture model systems. Copyrolysis of glucose-Asp mixtures led to the release of acrylic acid, attaining >5 mmol/mol Asp at 230 degrees C after 5 min. Spurious amounts of 3-butenamide were detected upon heating Gln together with a carbonyl source. Apparently, intramolecular cyclization is favored to procure 2-pyrrolidinone, reaching levels >3 mmol/mol above 230 degrees C. 2-Pyrrolidinone was also formed in comparable amounts in pyrolyzed sugar-Glu mixtures, indicating that the Maillard reaction may be an important contributor to the formation of 2-pyrrolidinone in certain cooked foods. The chemical route to acrylic acid and 3-butenamide is probably analogous to that described for acrylamide recently. Evidence is also presented that acrylic acid may be an intermediate in the formation of acrylamide, and yields could be augmented by coincubation of fructose-Asp with certain amino acids such as Gln, reaching approximately 5% of the yield obtained by the Asn route. A computational study to determine the reactivity of the vinylogous products indicated a reduced ability of 3-butenamide as compared to acrylamide to form stable intermediates by Michael nucleophilic addition. Acrylamide and acrylic acid exhibited a similar theoretical reactivity potential toward nucleophiles. No information is as yet available on the occurrence of acrylic acid in cooked foods. Extensive toxicological evaluation indicates that acrylic acid is of no concern at the amounts to be expected in foods.

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Section: Discussionmentioning

confidence: 99%