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

Olivia Ogilvie; Sarah Roberts; Kevin Sutton; Nigel Larsen; Juliet Gerrard; Laura Domigan

doi:10.1016/j.foodchem.2020.127903

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

Food Chem. 2021 Mar 15:340:127903. doi: 10.1016/j.foodchem.2020.127903. Epub 2020 Aug 26.

Authors

Olivia Ogilvie¹, Sarah Roberts², Kevin Sutton³, Nigel Larsen², Juliet Gerrard⁴, Laura Domigan⁵

Affiliations

¹ School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand; The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch Mail Centre, Christchurch 8140, New Zealand; Department of Chemical and Materials Engineering The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address: oogi280@aucklanduni.ac.nz.
² Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand; The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch Mail Centre, Christchurch 8140, New Zealand.
³ Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand; The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch Mail Centre, Christchurch 8140, New Zealand. Electronic address: kevin.sutton@plantandfood.co.nz.
⁴ School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand; School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address: j.gerrard@auckland.ac.nz.
⁵ School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Riddet Institute, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand; Department of Chemical and Materials Engineering The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address: l.domigan@auckland.ac.nz.

PMID: 32889205
DOI: 10.1016/j.foodchem.2020.127903

Abstract

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.

Keywords: Celiac; Food processing; Immunogenic peptide; Mass spectrometry; Peptidomics.

MeSH terms

Bread* / analysis
Celiac Disease
Digestion
Glutens / chemistry*
Glutens / immunology
Glutens / pharmacokinetics*
Humans
Peptide Fragments / analysis
Peptide Fragments / immunology
Proteolysis
Streptomyces / enzymology
Transglutaminases / chemistry
Transglutaminases / metabolism*
Triticum / chemistry

Substances

Peptide Fragments
Glutens
Transglutaminases

Supplementary concepts

Streptomyces mobaraensis