A A C C   2 0 0 0   A n n u a l   M e e t i n g

Several imaging techniques have been used to measure the bubble structure of bread doughs throughout processing, and to identify effects on bread texture. Doughs were prepared by a Chorleywood Bread Process, using single-cultivar flours and several mixing times. Gas volume fraction was calculated from dough density measurements. The size distribution of bubbles after mixing and first proof was measured by microscopy of thin sections, using digital image analysis. For doughs after moulding and during final proof, an X-ray computerised tomography (CT) scanner was used to image the internal structure non-invasively. Differences in texture were already apparent at the start of final proof for doughs prepared from wheat cultivars of differing quality. The CT scans also clearly showed the effects of single and four-piece moulding on the distribution and orientation of bubbles within the doughs. The development of these structures throughout proof was studied by proving doughs in a humidified box placed within the scanner. After baking, direct comparisons were also made between the CT images and the bread structure. Quantitative measurements of bread texture were made with newly developed digital image analysis software. For a constant rate of work input, longer mixing times were required for maximum loaf volume than for finest texture. Cultivars with greater protein strength required greater work input to achieve these optima.