Impact of post-harvest degradation of wheat gluten proteins by Fusarium culmorum on the resulting bread quality

This study was conducted to investigate the impact of wheat gluten protein degradation during storage in a dough and bread system due to different levels of fungal contamination with F. culmorum. Therefore, artificially infected grains were stored in a model system and analysed for their gluten content and quality. This revealed a substantial loss in wet gluten content and a weakening of the gluten network in the infected samples during storage. Subsequently, the samples were used to bake wholegrain breads and the obtained dough and breads were analysed. Reduced quality as a consequence of storage was found for all samples, but in the infected samples to a greater extent than in the healthy grains. The breads presented a reduced quality, mainly due to their high bake loss, deformed loaf shape and open crumb structure. The reason for these results was mainly found to be due to the increased enzymatic activities originating from the fungal metabolism. Furthermore, the deterioration of the bread quality after storage was independent of the level of initial infection. Consequently, this study demonstrates the importance of optimal storage conditions and the development of efficient methods to suppress fungal proliferation during storage, in order to reduce economic losses and ensure a consistent high quality of the resulting products.