Wheat bran-associated subaleurone and endosperm proteins and their impact on bran-rich bread-making

The functionality of wheat bran-associated subaleurone and endosperm proteins was investigated. The wheat cultivars Apache and Akteur were used as they displayed widely different subaleurone protein contents upon microscopic analysis. Brushing of their roller mill bran yielded a peripheral endosperm- and subaleurone-enriched flour fraction with a protein content of 15.1% and 22.1% for Apache and Akteur, respectively, compared to 10.0% and 12.8% for regular flour. The peripheral endosperm fraction of Akteur, but not Apache, displayed increased glutenin and gliadin contents and increased glutenin subunit crosslinking. Bread-making using bran subjected to heat treatment and particle size reduction indicated that the gluten quantity and quality of the bran-associated tissue, as well as its availability and vitality, significantly affected dough and bread properties. These findings were validated using four commercial bran samples and demonstrate the potential importance of heat stabilization and wheat selection when producing bran for bread-making.