Rapid high performance liquid chromatographic detection of furosine (?-n-2-furoylmethyl-l-lysine) in yogurt and cheese marketed in Turkey

Furosine (-N-2-furoylmethyl-L-lysine) content determination in the yogurt and different cheese types (pickled white, kasar, processed, canned tulum, blue-veined and mozzarella cheeses) marketed in Turkey was performed using ion-pair reversed-phase high performance liquid chromatography (RP-HPLC). Calibration study (R2 = 0.9999), analytical method validation and recovery studies gave satisfactory results. The lowest furosine values were observed in pickled white cheeses (5.35 ± 0.01 to 7.28 ± 0.02 mg100 g protein). All cheeses except pickled white showed furosine values between 182.16 ± 0.12 (canned tulum) and 261.32 ± 0.10 mg100 g protein (ripened kasar). The highest content of furosine was observed in whole yogurt (316.47 ± 0.17 mg100 g protein) which could be because of severe heat treatment and the addition of milk powder during the manufacturing process. The method provides a rapid, reproducible and accurate determination of this Amadori compound (-deoxy-fructosyl-lysine) in yogurt and cheese samples. © 2006, Blackwell Publishing.