Effect of pressure on processes modelling the Maillard reaction

Abstract

The Maillard reaction between tryptophan and glucose or xylose was studied as a function of pressure. Using model reactions, volumes of activation for the formation of the intermediate imine and the Amadori rearrangement and for the decomposition of the aminoketose were measured as -14, 8 and 17 cm'mol-', respectively. Pressure therefore accelerates the initial reactions but retards the formation of the final heterocyclic products and melanoidins. Oxygen was found to accelerate the latter reaction.

Insights into C–C Bond Cleavage Mechanisms in Dichloroacetonitrile Formation during Chlorination of Long-Chain Primary Amines, Amino Acids, and Dipeptides

“…The Δ G ⧧ values of the first two reactions (steps c1 and c2 ) are 13–15 kcal/mol both assisted by ClO – , while that of the last addition reaction (steps c3 ) is 25 kcal/mol assisted by four water molecules (see Text S2 for details) with the rate constant k calc of ∼10 –6 M –1 s –1 and reaction half-life of ∼10 years. Such a low k calc value agrees well with the fact that the addition reaction of olefin substituted with the relatively strong electron-withdrawing −CN group and HOCl is kinetically unfeasible to occur . This also suggests that Int 2 is a potentially detectable intermediate, that is expected to be observed in experiment in the future.…”

The effect of high pressure on the formation of volatile products in a model Maillard reaction

“…This step is formally similar to the decomposition of the Amadori rearrangement product which has been previously shown also to have a positive volume of activation. 7 Retardation of the rate of decomposition of the ARP in forming melanoidins was further confirmed in the present work although it now appears that this only applies at neutral or acidic pH while at high pH pressure actually accelerates browning. 12 Neutral proton transfers are usually accompanied by no volume change so the various enolizations are unlikely to be contributing significantly to the volume of activation.…”

Structural and Emulsifying Properties of Soybean Protein Isolate–Sodium Alginate Conjugates under High Hydrostatic Pressure

“…As shown in Table 1, the HHP treatment significantly reduced the absorbances at 294 nm and 420 nm (p < 0.05) compared to those of the SPI-SA-0.1 conjugate, indicating its inhibitory effect on the SPI-SA Maillard reaction. Isaacs and Coulson [36] and Martínez, et al [37] found that the intermediate and advanced stages of the Maillard reaction were suppressed, which indicated a retardation of the degradation of the Amadori rearrangement products. The values represent means ± standard deviations; The ranges (a-d) represent the row-wise decreasing magnitudes of the absorbances (p < 0.05).…”