Comparison of Gluten Extraction Protocols Assessed by LC-MS/MS Analysis

Area of Science:

• Food science
• Analytical chemistry
• Biochemistry

Background:

• Gluten detection accuracy is crucial for managing celiac disease (CD) and nonceliac gluten sensitivity (NCGS).
• Inefficient gluten extraction leads to under-estimation of gluten content, posing health risks.
• Reliable analytical methods require optimized and reproducible extraction protocols.

Purpose of the Study:

• To evaluate the efficiency and reproducibility of five different gluten extraction protocols.
• To identify optimal methods for gluten extraction for accurate gluten quantitation.
• To assess the impact of multi-step protocols on protein co-extraction.

Main Methods:

• Liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM-MS) was employed.
• Five distinct gluten extraction protocols were investigated.
• Protein identification and quantification were performed across all extracted fractions.

Main Results:

• The IPA/DTT and two-step protocols demonstrated high enrichment for gluten proteins (55-86% and 41-68% of identifications).
• Both IPA/DTT and two-step protocols exhibited excellent reproducibility (CV < 15%).
• Multi-step protocols revealed significant protein co-extraction across fractions, indicating complex behavior.

Conclusions:

• The IPA/DTT and two-step protocols are efficient and reproducible for gluten extraction.
• Careful examination of all fractions is necessary in multi-step extraction protocols.
• Optimized gluten extraction is fundamental for accurate gluten testing and dietary management.