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Taubman et al. published a paper in the MBAA Technical Quarterly that reported that a strain of ''L. brevis'', ''L. curvatus'', ''L. plantarum'', and ''Pediococcus pentosaceus'' that were found to reduce gluten in sourdough bread making had a similar functionality when fermenting wort. They found that these strains reduced gluten to undetectable levels in 5-7 weeks. However, they lost the ability to reduce gluten when co-fermented with yeast, probably due to competition from the yeast. The wort that was fermented with only one of the lactic acid bacteria strains and no yeast resulted in an unpleasant fermented beverage. The researchers also reported analyzing commercial sour beers and finding some with reduced levels of gluten, but did not offer an explanation on how to accomplish this <ref>[https://www.mbaa.com/publications/tq/tqPastIssues/2018/Pages/TQ-55-1-0305-01.aspx Microbial Gluten Reduction in Beer Using Lactic Acid Bacteria and Standard Process Methods. Brett F. Taubman, Stephan Sommer, Jacob Edwards, Travis Laws, Logan Hamm, and Brenton A. Frank. 2018. DOI: https://doi.org/10.1094/TQ-55-1-0305-01.]</ref><ref>[http://masterbrewerspodcast.com/094-microbial-gluten-reduction-in-beer-using-lactic-acid-bacteria-and-standard-process-methods "094: Microbial Gluten Reduction in Beer Using Lactic Acid Bacteria and Standard Process Methods". Master Brewers Association Podcast. June 2018.]</ref>. The researchers hypothesized that the cause of the off-flavors in the 100% ''Lactobacillus'' fermentations were due to oxygen and hydrogen sulfide in the headspace of the fermenters and that further experiments with purging the oxygen and hydrogen sulfide from the head space should be done, however, previous research has shown that wort fermented with only ''Lactobacillus'' does not fully attenuate which leaves ample amounts of residual sugar available for contaminants to potentially produce off-flavors (assuming they can withstand the low pH produced by the lactic acid bacteria fermentation). Performing long fermentations with only ''Lactobacillus'' are generally not recommended due to the residual sugar left by 100% ''Lactobacillus'' fermentation. For example, it is recommended to [[Wort_Souring#Souring_in_the_Boiler_.28Kettle_Sour.29|kettle sour]] within 24-48 hours in order to lower the risk of off-flavor development. Attenuation/ethanol/final gravity measurements were not reported in this study.
Another study by [http://agris.fao.org/agris-search/search.do?recordID=LV2019000334 Bradauskiene et al. (2019)] looked at the reduction of gluten by four different probiotic ''Lactobacillus'' strains. They first performed a "wet fractionation" which is a method of separating solids from the liquid wort. This is a method that has been shown to physically remove a portion of gluten from the liquid and is done by centrifuging the wheat/water mixture. Separate fractions of starch, fiber, and bran were obtained and then each separately centrifuged. The centrifuged liquid of each fraction (starch, fiber, and bran) was separated split into the starch 4 different fermenters and each fermented with a different ''Lactobacillus' strain (two strains of ''L acidophilus'', one strain of ''L. plantarum'', and fiber fractionsone strain of ''L. brevis''). The results of the study showed that different strains reduce gluten by different amounts after 24 hours of fermentation, but overall the amount of gluten reduction was too small to achieve the 20 mg/kg of gluten that is required to label something as "gluten free". The gluten content was reduced by a significant amount in the fiber portion which was initially 7800 mg/kg and went down to 2200-2800 mg/kg depending on the strain used with the greatest reduction by one of the ''L. acidophilus'' strains. The starch portion had low gluten to begin with at 80 mg/kg and was reduced to 12-30 mg/kg . The bran fraction had around 33750 mg/kg, but the gluten reduction was not reported for it. While some strains of ''Lactobacillus'' could be used to make a starch-only containing liquid gluten-free, they were unable to achieve enough gluten reduction with the fiber and bran fractions of wheat <ref name="Bradauskiene_2019" />.
==See Also==