P2-09 Detection of Gluten in a Barley-Malt Beer Produced with and without a Prolyl Endopeptidase Enzyme

Tuesday, July 11, 2017
Exhibit Hall (Tampa Convention Center)
Magdalena Naziemiec , Illinois Institute of Technology , Chicago , IL
Wanying Cao , Illinois Institute of Technology , Chicago , IL
Liyun Zhang , Illinois Institute of Technology , Chicago , IL
Nicholas Smith , University of Wisconsin , Madison , WI
Matthew Arbuckle , University of Wisconsin , Madison , WI
Arnoldo Lopez-Hernandez , University of Wisconsin , Madison , WI
Lanlan Yin , U.S. Food and Drug Administration , College Park , MD
Katherine Fiedler , U.S. Food and Drug Administration , College Park , MD
Binaifer Bedford , U.S. Food and Drug Administration , Bedford Park , IL
Lauren Jackson , U.S. Food and Drug Administration , Bedford Park , IL
Introduction:  Consumers with celiac disease must avoid gluten to maintain good health. Unfortunately, detection of gluten in hydrolyzed and fermented foods poses an analytical challenge.

Purpose:  This study examined how the brewing process and the addition of a prolyl endopeptidase enzyme (Brewers Clarex®) affected gluten detection in beer brewed with barley malt using gluten-specific ELISA and lateral flow devices (LFDs).

Methods:  Beer (55 L) was brewed from barley malt in a pilot plant, and Clarex®was added at varying dosages [0 (control), 0.017, 0.034, 0.068 ml/liter] to equal volumes (13 L) of beer before fermentation. Beer samples were collected until 8.5 weeks fermentation/aging. Five ELISA tests (Ridascreen Gliadin sandwich, Ridascreen Gliadin Competitive, Aller-Tek Gluten, Morinaga Wheat/Gluten, AgraQuant G12) and four LFD kits (AgraStrip G12, ELISA Systems sandwich, ELISA Systems competitive, Morinaga Gluten/Gliadin IIR) were used to detect gluten in samples. Pilot plant trials and analytical tests were completed in triplicate.

Results:  Gluten concentrations in unfermented beer ranged from 96 to 191 ppm gluten across three trials as measured with the AgraQuant G12 ELISA [LOQ, 4 ppm]. After 8.5 weeks fermentation/aging, control beer had <LOQ 10 ppm gluten, while the Clarex®-treated beer (0.017, 0.034, 0.068 ml/liter) had 4 to 21 ppm gluten, <LOQ 35 ppm gluten, and <LOQ 23 ppm gluten, respectively (≤6% CV for all samples). Control beer fermented/aged for 8.5 weeks and subjected to a filtration treatment had up to seven ppm gluten, while comparable Clarex®-treated beer had gluten levels <LOQ of the AgraQuant ELISA. While the AgraStrip LFD tests gave positive results for all unfiltered beer samples, only the control treatment gave positive results for filtered beers.

Significance:  Variability exists when determining gluten content in hydrolyzed and fermented foods. Complementary methods, such as mass spectrometry, are needed to detect gluten in fermented and hydrolyzed foods.