Breads from white grain sorghum: Rheological properties and baking volume with exogenous gluten protein

Bread made with a composite flour containing sorghum is nutritionally valua ble. However, sorghum alone lacks the functional proteins for breadmaking. This study investigated the rheological properties and bread baking potenti al of a sorghum-based composite flour system containing various amounts of vital wheat gluten (exogenous gluten protein). Mixograph and Kieffer tests result showed that exogenous gluten protein significantly enhanced the comp osite dough's strength. At fixed gluten protein levels, as sorghum flour in creased, water absorption decreased slightly, dough strength and extensibil ity decreased, and mixing time increased significantly. Exogenous gluten pr oteins when added in the form of vital wheat gluten into the composite flou r without wheat flour could not form an appropriate gluten network for brea d making. The interaction between exogenous and endogenous proteins in whea t flour and in the composite flour contributed greatly to the rheological p roperties of the sorghum composite dough and bread volume.