Measuring AGEs requires total acid or enzymatic protein hydrolysis with concomitant GC or LC separation with mass detection.
Viatmin C oxidation products play a role in the browning process of lens crystallins.
The Maillard reaction or “nonenzymatic browning” is a complex series of reactions between reducing carbohydrates and nucleophylic residues and N-terminal amino groups of proteins. In the first step of this processes, reducing sugars typically from a rather labile Schiff bases adduct, which as a rule rearrange to the more stabile Amadori products. In complex reaction pathways via dicarbonyl intermediates the Amadori compounds are slowly degraded to a plethora of compounds summarily subsumed under the term advanced glycation end products (AGEs).
Most AGEs are formed from aminoketoses via highly reactive dicarbonyl intermediates such as 1-deoxyglucosone, 3-deoxyglucosone, 1,4-dideoxy-5,6-dioxoglucosone, glyoxal and methylglyoxal.