The effect of a rotary extrusion divider on commercial white pan bread dough

The baking industry has been looking for ways to reduce costs, produce more bread, and improve product quality for many years. New equipment and procedures have been introduced to increase production speed, but quality has declined. There has been speculation that major defects (decline in quality) have been due to damage to the dough resulting from its mechanical processing. This study was conducted to determine to what extent damage to commercial white pan bread dough results from the use of a rotary extrusion divider. The study was conducted at a commercial bread plant and a pilot plant at the American Institute of Baking (AIB). Transmission electron microscopy (TEM) was used to study changes in dough structure at three sampling points; immediately after mixing, immediately after dividing, and just before moulding. TEM micrographs showed commercial divider dough samples were overmixed. Gluten appeared broken and ruptured into smaller irregular strands with more and larger vacuoles. TEM micrographs of the dough from a commercial rounder showed some repair of proteins had occurred, but large vacuoles still existed in the gluten sheets.; Physical dough properties were measured by a texture analyzer and two dough density methods. The texture analysis showed decreases in elasticity, resistance to extension, and less work input by the divider dough samples compared to the mixer samples. True dough density showed that there was a significantly higher density in divider dough samples (1.72 g/cm3) versus mixer (1.32 g/cm3) and moulding (1.11 g/cm 3).; Protein composition changes were followed by Size-Exclusion High Performance Liquid Chromatography (SEC-HPLC). Soluble polymeric proteins (SPP) increased to 17.7% and insoluble polymeric proteins (IPP) decreased to 35.5% in the divider dough samples over the mixer samples. The ratio of IPP to SPP was smallest in the divider dough samples at 2.00. SEC-HPLC showed a shift to more SPP, indicating decreased strength and resistance as the dough exited the divider.; Results of this study showed that the damage occurred in the proteins in the divider. The resting time of 65 to 75 seconds before molding appears insufficient for the protein to repair. This affected the gas holding abilities of white pan bread dough, resulting in product quality defects.