Determination of advanced glycation endproducts by LC-MS/MS in raw and roasted almonds (Prunus dulcis)

A sensitive and reliable LC-(ESI)MS/MS method was developed and validated for the simultaneous analysis of five common advanced glycation endproducts (AGEs) after enzymatic digestion in raw and roasted almonds. AGEs included carboxymethyl-lysine (CML), carboxyethyl-lysine (CEL), pyralline (Pyr), argpyrimidine (Arg-p), and pentosidine (Pento-s). This method allows accurate quantitation of free and AGE-protein adducts of target AGEs. Results indicate that CML and CEL are found in both raw and roasted almonds. Pyr was identified for the first time in roasted almonds and accounted for 64.4% of free plus bound measured AGEs. Arg-p and Pento-s were below the limit of detection in all almond samples tested. Free AGEs accounted for 1.3-26.8% of free plus bound measured AGEs, indicating that protein-bound forms predominate. The roasting process significantly increased CML, CEL, and Pyr formation, but no significant correlation was observed between these AGEs and roasting temperature.