Nuclear chemistry

Glutamic acid

Quantum mechanics

Amino acid

Pyrazine

Biochemistry

Food science

Stereochemistry

Medicinal chemistry

Aspartic acid

Physics

Organic chemistry

Kinetics

Maillard reaction

Chemistry

Ascorbic acid

Browning

Food Chemistry

The kinetics of browning and the correlation between browning products (BPs) and pyrazine compounds were investigated by heating equimolar l-ascorbic acid (ASA)/acidic amino acids under weak alkaline conditions at 120-150°C for 10-120min. The formations of BPs and pyrazine compounds from the reaction were monitored by UV-vis and SPME-GC-FID, respectively. The formation of BPs in both ASA/l-glutamic acid and ASA/l-aspartic acid model reaction systems followed zero order reaction kinetics with activation energies (Ea) of 90.13 and 93.38kJ/mol, respectively. ASA/l-aspartic acid browned at a slightly higher rate than ASA/l-glutamic acid. The total concentration of pyrazine compounds was highly and positively correlated with that of BPs. Based on the observed kinetic data, the formation mechanisms of BPs and pyrazine compounds were proposed.

Kinetics of browning and correlations between browning degree and pyrazine compounds in l-ascorbic acid/acidic amino acid model systems