title: Digestibility of gluten proteins is reduced by baking and enhanced by starch digestion.
abstract: METHODS
  Resistance of proteins to gastrointestinal digestion may play a role in determining immune-mediated adverse reactions to foods. However, digestion studies have largely been restricted to purified proteins and the impact of food processing and food matrices on protein digestibility is poorly understood.
  
  
  RESULTS
  Digestibility of a total gliadin fraction (TGF), flour (cv Hereward), and bread was assessed using in vitro batch digestion with simulated oral, gastric, and duodenal phases. Protein digestion was monitored by SDS-PAGE and immunoblotting using monoclonal antibodies specific for celiac-toxic sequences (QQSF, QPFP) and starch digestion by measuring undigested starch. Whereas the TGF was rapidly digested during the gastric phase the gluten proteins in bread were virtually undigested and digested rapidly during the duodenal phase only if amylase was included. Duodenal starch digestion was also slower in the absence of duodenal proteases.
  
  
  CONCLUSIONS
  The baking process reduces the digestibility of wheat gluten proteins, including those containing sequences active in celiac disease. Starch digestion affects the extent of protein digestion, probably because of gluten-starch complex formation during baking. Digestion studies using purified protein fractions alone are therefore not predictive of digestion in complex food matrices.
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK.
authors.forename: Frances
authors.initials: F
authors.lastname: Smith
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Pan
authors.affiliation: Institut Polytechnique laSalle Beauvais, Beauvais, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Bellido
authors.affiliation: Institute of Food Research, Norwich, UK.
authors.forename: Geraldine A
authors.initials: GA
authors.lastname: Toole
authors.affiliation: Campden BRI, Chipping Campden, UK.
authors.forename: Fred K
authors.initials: FK
authors.lastname: Gates
authors.affiliation: Reacta Biotech Limited, Manchester, UK.
authors.forename: Martin S J
authors.initials: MS
authors.lastname: Wickham
authors.affiliation: Rothamsted Research, Harpenden, UK.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Shewry
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, UK.
authors.forename: Serafim
authors.initials: S
authors.lastname: Bakalis
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Padfield
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK.
authors.forename: E N Clare
authors.initials: EN
authors.lastname: Mills
mesh_terms: D000681:Amylases / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000032:analysis; D001939:Bread; D003296:Cooking; D004063:Digestion; D004386:Duodenum / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005433:Flour; D005903:Gliadin / Q000378:metabolism; D005983:Glutens / Q000737:chemistry / Q000276:immunology / Q000378:metabolism* / Q000493:pharmacokinetics; D006801:Humans; D015151:Immunoblotting; D013213:Starch / Q000378:metabolism* / Q000493:pharmacokinetics
chemical_list: D000911:Antibodies, Monoclonal; D005983:Glutens; D013213:Starch; D005903:Gliadin; D000681:Amylases
keywords: Allergen; Baking; Celiac; Digestion; Gluten