Changes of gluten protein composition during sourdough fermentation in rye flour

Background and Objectives

Celiac disease (CD) is an immune-mediated condition triggered by gluten consumption. Although more studies stated that gluten proteins are partially degrading during sourdough fermentation, it is still unclear whether the CD toxic epitopes are affected. Our aim was to examine the effect of controlled sourdough fermentation on the gluten content and composition with different sourdough starters in rye flour.

Findings

Despite significant changes in protein size distribution and a decrease in secalin types confirmed by high-performance liquid chromatography methods, the enzyme-linked immunosorbent assay results showed increased gluten content after fermentation. The incomplete degradation of gluten and the potential resistance of celiac toxic epitopes may explain our results. As part of the R5 antibody binding, epitopes are supposed to be unavailable in the native form of secalins; they might be released and become accessible in the smaller protein fragments.

Conclusions

In comparison of the effect of different starter cultures, the results show that the different microbiological composition of the sourdough samples might be the reason for the differences in the protein degradation.

Significance and Novelty

Results highlight the importance of a deeper investigation of the effects of gluten protein degradation on CD toxicity and the standardization of the fermentation process.