Production of dry-cured formed ham with different concentrations of microbial transglutaminase: Mass spectrometric analysis and sensory evaluation

Dry-cured formed hams were produced with different concentrations of microbial transglutaminase (TG; 0.05, 0.1, 0.2, 0.5, and 0.8% Activa PB) and glucono-delta-lactone as control. A sensory evaluation was performed during a 43-day storage to determine cohesion, cavities, and local separation of dry-cured formed ham. Rising TG concentrations resulted in a slight increase in the evaluation of all sensory parameters, whereas amounts of TG higher than 0.5% led to an only very minor improvement. Dry-cured formed ham samples were analyzed by a sensitive HPLC-MS/MS method for the detection of TG using five tryptic marker peptides. Even very small amounts of Activa PB (0.05%) were detectable unambiguously. A decrease of TG detectability during the storage time of dry-cured formed ham was not observed. Using four marker peptides, no false-positive or -negative results were obtained. The amounts of two marker peptides were calculated using isotope-labeled peptides. They showed high correlations to the amount of Activa PB (R2 > 0.995).