Gluten-degrading proteases in wheat infected by Fusarium graminearum – protease identification and effects on gluten and dough properties.

Abstract

Recently, we have observed a relationship between poor breadmaking quality and protease activities 6 related to fungal infection. This study aims to identify potential gluten-degrading proteases secreted by 7 fungi and to analyse effects of these proteases on rheological properties of dough and gluten. Fusarium 8 graminearum infected grain was used as a model system. Zymography showed that serine-type 9 proteases secreted by F. graminearum degrade gluten proteins. Zymography followed by LC-MS/MS 10 analyses predicted one serine carboxypeptidase and seven serine endo-peptidases to be candidate fungal 11 proteases involved in gluten degradation. Effects of fungal proteases on the time-dependent rheological 12 properties of dough and gluten were analysed by small amplitude oscillatory shear rheology and large 13 deformation extensional rheology. Our results indicate that fungal proteases degrade gluten proteins not 14 only in the grain itself, but also during dough preparation and resting. Our study gives new insight into 15 fungal proteases and their potential role in weakening of gluten.

Gluten-degrading proteases in wheat infected by Fusarium graminearum – protease identification and effects on gluten and dough properties.