Nonenzymatic Browning Reaction of Essential Amino Acids:  Effect of pH on Caramelization and Maillard Reaction Kinetics

Abstract

The interaction between glucose and essential amino acids at 100 degrees C at pH values ranging from 4.0 to 12.0 was investigated by monitoring the disappearance of glucose and amino acids as well as the appearance of brown color. Lysine was the most strongly destroyed amino acid, followed by threonine which induced very little additional browning as compared with that undergone by glucose. Around neutrality, the nonenzymatic browning followed pseudo-zero-order kinetics after a lag time, while the glucose and amino acid losses did not follow first-order kinetics at any of the pH values tested. Glucose was more strongly destroyed than all of the essential amino acids, the losses of which are really small at pH values lower than 9.0. However, glucose was less susceptible to thermal degradation in the presence of amino acids, especially at pH 8.0 with threonine and at pH 10.0 with lysine. The contribution of the caramelization reaction to the overall nonenzymatic browning above neutrality should lead to an overestimation of the Maillard reaction in foods.

Impact of chemical pre-treatments on the acrylamide formation and sensorial quality of potato crisps

“…This difference was mostly pronounced for L-lysine. This is not surprising since L-lysine is known as a very reactive amino acid in the Maillard reaction, due to the a-and e-amino groups (Ajandouz & Puigserver, 1999;Becalski, Lau, Lewis, & Seaman, 2003). Also in combination with acetic acid, L-lysine appeared to induce more browning compared to glycine.…”

Exaggerated expectations in ancient starch research and the need for new taphonomic and authenticity criteria

“…The Maillard reaction, the abiotic reaction of amino acid and carbohydrate species, produces complex chemistries proposed as one of the routes of preservation of organic matter in soils and kerogens (Larter and Douglas 1980). This reaction, which occurs under ambient conditions and at high temperatures during cooking, produces a variety of high molecular mass pigmented products or "melanoidins" (Ajandouz and Puigserver 1999;Hill et al 2005;Hwang et al 2011). Figure 4 shows the results of a Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) study.…”

Effect of xylose on the molecular and particle size distribution of peanut hydrolysate in Maillard reaction system

“…27 Alanine and methionone were found to be the least reactive amino acids, with only 3.92% and 12.43% losses, respectively, which was in agreement with the report of Ajandouz and Puigserver. 28 Some amino acids markedly decreased after adding xylose to 2%, such as serine, alanine, methionine and isoleucine. However, as the xylose concentration was further enhanced, all the individual amino acids were slightly decreased.…”