The use of microbial transglutaminase in a bread system: A study of gluten protein structure, deamidation state and protein digestion

Microbial transglutaminase (mTG) catalyses the formation of protein crosslinks, deamidating glutamine in a side-reaction. Gluten deamidation by human tissue transglutaminase is critical to activate celiac disease pathogenesis making the addition of mTG to wheat-based products controversial. The ability of mTG (0-2000 U.kg(-1)) to alter gluten's structure, digestibility and the deamidation state of six immunogenic gluten peptides within bread was investigated. Gluten's structure was altered when mTG exceeded 100 U.kg(-1), determined by confocal microscopy, extractability and free sulfhydryl assays. The effect of mTG on six immunogenic peptides was investigated by in vitro digestion (INFOGEST) and mass spectrometry. The addition of mTG to bread (0-2000 U.kg(-1)) did not alter the deamidation state or digestibility of the immunogenic peptides investigated. Overall, this investigation indicated that the addition of mTG to bread does not create activated gluten peptides. This analysis provides evidence for risk assessments of mTG as a food processing aid.

Automated summary

The study investigated the impact of adding different concentrations of mTG to bread on gluten structure, digestibility, and immunogenic peptides. The results showed that the addition of mTG did not affect the deamidation state and digestibility of immunogenic peptides, indicating that mTG addition does not produce activated gluten peptides.