Formation Kinetics of 2,5-Dimethylpyrazine and 2-Methylpyrazine in a Solid Model System Consisting of Amioca Starch, Lysine, and Glucose

A new analysis using the fractional conversion technique was applied to determine the formation kinetics of 2,5-dimethylpyrazine and 2-methylpyrazine in a solid model system containing 4.5% (w/w) lysine, 5.5% glucose, and amioca starch with 10% moisture (dry basis) from 80 to 120 °C. The reaction order and kinetic parameters (rate constants and activation energy) were determined through a parameter estimation technique based on least-squares fit. The formation rate of both pyrazines followed a first-order reaction model. No significant differences were observed for the activation energies and rate constants for 2,5-dimethylpyrazine and 2-methylpyrazine, suggesting the production of these pyrazines was controlled by the same rate-limiting step. The activation energy was 13.5 kcal/mol. Keywords: Kinetics; 2,5-dimethylpyrazine and 2-methylpyrazine; solid state; fractional conversion