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Kinetics of Acrylamide Formation/Elimination Reactions as Affected by Water Activity
Author(s) -
de Vleeschouwer Kristel,
Plancken Iesel Van der,
Van Loey Ann,
Hendrickx Marc E.
Publication year - 2008
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp060389f
Subject(s) - acrylamide , maillard reaction , chemistry , reaction rate constant , water activity , kinetics , reaction rate , asparagine , elimination reaction , chemical kinetics , water content , thermodynamics , organic chemistry , catalysis , polymer , physics , enzyme , geotechnical engineering , quantum mechanics , engineering , copolymer
The influence of water activity on the kinetics of acrylamide formation and elimination reaction was investigated using low‐moisture equimolar asparagine‐glucose model systems, which were heated at temperatures between 120 and 200 °C for variable heating times. To determine the water content corresponding to the water activities tested, a sorption moisture isotherm was constructed experimentally. The acrylamide concentrations measured at different water activities could be modeled on the basis of a reaction scheme including not only acrylamide formation and elimination reactions but also an alternative Maillard reaction between both reactants. The corresponding rate constants and activation energies were estimated using nonlinear regression analysis. Whereas the rate constant for acrylamide formation varied only slightly with the initial water activity of the model system, the elimination rate constant showed a clear minimum around a water activity of 0.82. The opposite trend, namely, a maximum at a water activity of 0.82, was found for the Maillard reaction rate constant as a function of water activity, which confirms data from literature. The activation energies for the different reactions changed in a comparable way as the corresponding rate constant with water activity.