Germinated barley foodstuff (GBF) contains insoluble protein and dietary fiber, and has the potential to attenuate diarrhea and colonic mucosal damage in colitis. Since GBF contains a poorly digested protein fraction, this protein may be transferred to and absorbed in the colon. It may therefore be possible to detect the GBF antigen in colitis patients with dysfunctional colonic mucosal barrier defense. In this study, the antigenic potency of GBF was examined in vivo and in vitro. Using the AOAC method, the indigestible fraction of GBF (dietary fiber) was obtained, and the poorly digested protein fraction in GBF was determined. Using Sprague Dawley rats with chronic colitis induced by dextran sulfate sodium (DSS, 2.5% in diet), a GBF and control diet were administered, and total and specific serum immunoglobulin E (IgE) against intestinal contents and the soluble GBF protein were determined. In addition, reactivity between serum and intestinal content were examined by gel electrophoresis mobility shift assay (EMSA). GBF showed relatively low protein digestibility (47%) because of its low solubility in neutral pH. Total serum IgE in both dietary groups was not significantly different, and specific IgE antibodies against intestinal contents and the soluble GBF protein were not significantly different. In addition, supershifts were not observed in either dietary group by EMSA. The possible antigenicity of oral GBF was considered to be low in this colitis model.

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