Tracking Gluten throughout Brewing Using N-Terminal Labeling Mass Spectrometry

Area of Science:

• Food Science
• Biochemistry
• Immunology

Background:

• Celiac disease is triggered by gluten in grains.
• Fermentation can produce immunotoxic gluten fragments.
• Characterizing these fragments is crucial for managing celiac disease.

Purpose of the Study:

• To characterize gluten-derived polypeptides during bench-scale brewing.
• To evaluate the immunotoxic potential of these fragments.
• To identify stable, potentially harmful peptides in fermented products.

Main Methods:

• N-terminal labeling mass spectrometry was used to track gluten hydrolysates.
• Protein hydrolysates were analyzed at each brewing stage: malting, mashing, boiling, fermentation, and aging.
• Immunotoxicity was assessed by comparing peptide sequences to known celiac-stimulating peptides.

Main Results:

• Gliadin hydrolysis varied by protein region and brewing stage; termini were hydrolyzed, but central regions remained stable.
• Most hydrolysis occurred during malting, while most precipitation occurred during boiling.
• Yeast addition created new cleavage sites but did not achieve complete hydrolysis, with clinically relevant peptides consistently detected.

Conclusions:

• Brewing processes partially degrade gluten, but immunotoxic peptides persist.
• The central regions of gliadins are resistant to hydrolysis during brewing.
• N-terminal labeling mass spectrometry is a novel method for tracking gluten fate and identifying potential biomarkers for hydrolyzed gluten in fermented foods.