A randomised, double-blind, cross-over trial to evaluate bread, in which gluten has been pre-digested by prolyl endoprotease treatment, in subjects self-reporting benefits of adopting a gluten-free or low-gluten diet

Dinka Rees, Grietje Holtrop, Gemma Chope, Kim-Marie Moar, Morven Cruickshank, Nigel Hoggard

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The aim of the present study was to determine if the enzyme Aspergillus niger prolyl endoprotease (ANPEP), which degrades the immunogenic proline-rich residues in gluten peptides, can be used in the development of new wheat products, suitable for gluten sensitive (GS) individuals. We have carried out a double-blind, randomised, cross-over trial with two groups of adults; subjects, self-reporting benefits of adopting a gluten-free or low-gluten diet (GS) n=16 and a control non-GS group n=12. For the trial, volunteers consumed four wheat breads: normal bread, bread treated with 0.8% or 1% ANPEP and low-protein bread made from biscuit flour. Compared to controls, GS subjects had a favourable cardiovascular lipid profile - lower LDL (4.0 ± 0.3 vs. 2.8 ± 0.2 mmol/L; P=0.008) and LDL/HDL ratio (3.2 ± 0.4 vs. 1.8 ± 0.2; P=0.005) and modified haematological profile. The majority of the GS subjects followed a low-gluten lifestyle, which helps to reduce the GI symptoms severity. The low-gluten lifestyle does not have any effect on the quality of life, fatigue or mental state of this population. Consumption of normal wheat bread increased GI symptoms in GS subjects compared with their habitual diet. ANPEP lowered the immunogenic gluten in the treated bread by approximately 40%. However, when compared to the control bread for inducing GI symptoms, no treatment effects were apparent. ANPEP can be applied in the production of bread with taste, texture and appearance comparable to standard bread.
Original languageEnglish
Pages (from-to)496-506
Number of pages11
JournalBritish Journal of Nutrition
Issue number5
Early online date6 Mar 2018
Publication statusPublished - 14 Mar 2018



  • gluten sensitive
  • gastrointestinal symptoms
  • lipid profile
  • enzyme

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