title: Prevalence and stability of lysozyme in cheese.
abstract: The use of the preservative and potential allergen hen egg white lysozyme in cheese production has to be declared. In the present study, an HPLC method with fluorescence detection (HPLC-FLD) was optimised and validated for the analysis of lysozyme in cheese. Lysozyme was detected in concentrations between 30.8 and 386.2mg/kg cheese in 30 out of 46 analysed commercial cheese samples. During cheese production and storage for 0-54weeks a lysozyme satellite peak (LSP) was detected, which totals up to 18% of the lysozyme content. Mass spectrometry and peptide mass fingerprint revealed that LSP possesses the same primary structure as lysozyme. Since disulphide scrambling could not be detected, LSP was assigned to a conformational isomer of lysozyme. As a consequence, LSP was included in the HPLC-FLD analysis of lysozymes in cheese.
authors.affiliation: Department of Chemistry and Pharmacy, Food Chemistry, Emil-Fischer-Center, University of Erlangen-Nuremberg, Schuhstr. 19, 91052 Erlangen, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Schneider
authors.affiliation: Bavarian Health and Food Safety Authority, Eggenreuther Weg 43, 91058 Erlangen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Werkmeister
authors.affiliation: Institute of Biochemistry, Emil-Fischer-Center, University of Erlangen-Nuremberg, Fahrstr. 17, 91054 Erlangen, Germany.
authors.forename: C-M
authors.initials: CM
authors.lastname: Becker
authors.affiliation: Department of Chemistry and Pharmacy, Food Chemistry, Emil-Fischer-Center, University of Erlangen-Nuremberg, Schuhstr. 19, 91052 Erlangen, Germany. Electronic address: monika.pischetsrieder@lmchemie.uni-erlangen.de.
authors.forename: M
authors.initials: M
authors.lastname: Pischetsrieder
keywords: Cheese; Fluorescence detection; HPLC; Hen egg white lysozyme; Lysozyme degradation