The
enzyme transglutaminase 2 (TG2) plays a crucial role in the initiation of
celiac disease by catalyzing the deamidation of
gluten peptides. In susceptible individuals, the deamidated
peptides initiate an immune response leading to
celiac disease. Several studies have addressed lactic fermentation plus addition of
enzymes as a means to degrade
gluten in order to prevent adverse response in celiacs. Processing for complete
gluten degradation is often harsh and is not likely to yield products that are of comparable characteristics as their
gluten-containing counterparts. We are concerned that incomplete degradation of
gluten may have adverse effects because it leads to more available TG2-binding sites on
gluten peptides. Therefore, we have investigated how
lactic acid fermentation affects the potential binding of TG2 to
gluten protein in wheat flour by means of estimating TG2-mediated transamidation in addition to measuring the available TG2-binding motif QLP, in α2-gliadin. We show that lactic fermentation of wheat flour, as slurry or as part of sourdough bread, did not decrease the TG2-mediated transamidation, in the presence of a primary
amine, to an efficient level (73%-102% of unfermented flour). Nor did the lactic fermentation decrease the available TG2 binding motif QLP in α2-gliadin to a sufficient extent in sourdough bread (73%-122% of unfermented control) to be useful for celiac safe food.