2-Furoylmethyl amino acids as indicators of Maillard reaction during the elaboration of black garlic

This study reports the formation of 2-furomethyl-amino acids (2-FM-AA) as indicators of Maillard reaction (MR) in black garlic elaboration, followed by the determination of furosine by ion-pair RP-HPLC-UV. The method was assessed for accuracy, repeatability and detection and quantitation limits indicating its adequacy. Traditional procedure of black garlic obtainment and the inclusion of convective drying (CDP) and ohmic heating (OHP) were assayed. For comparison purposes, three commercial black garlic samples were used. Together with furosine (2-FM-lysine), 2-furoylmethyl-gamma-aminobutyric acid and 2-FM-arginine were detected. Levels of furosine were higher in CDP (46.6-110.1 mg/100 g protein) than in OHP (13.7-42.0 mg/100 g protein) samples, probably due to the most severe processing conditions used in the former. These results highlight the suitability of 2-FM-AA as chemical indicators to monitor the process of black garlic elaboration in order to obtain high quality products.