Dough expansion capacity as a research tool

Two main factors appear to control bread-making performance—the dough rheological properties and the gas cell stability. To study these factors, a novel instrument and methodology was developed to allow measurements of expansion capacity of dough subjected to low pressures. A vacuum pump attached to a desiccator equipped with a dough height tracker was introduced for the measurement of dough expansion. The dough height and time were measured at each processing stage of dough (after mixing, 52-min fermentation, 77-min fermentation, 90-min fermentation, and after proofing) and at five different negative pressures (29, 26, 23, 20, and 17 in. of Mercury). Rapid expansion of dough pieces caused by subjecting them to different negative pressures gave maximum heights, which compared well with the final baked loaf height. However, after mixing, negative pressures below 29 in. of Hg negative pressure were insufficient to expand doughs to their full capacity. There was good reproducibility in maximum dough height and time to reach maximum dough height. The application of the technique requires 1–5 min at 29 in. of Hg negative pressure depending on the processing stage.; This technique was used to study the effects of potassium bromate (oxidant), natural flour lipids, and dough conditioners, at different stages of baking. It was shown that the addition of an optimum level of bromate (30-ppm) has effects only at proofing and baking stages, and is consistently related to the changes in loaf volume and loaf height in bread from untreated and defatted flours. Information on the contribution of natural flour lipids at different bread processing stages was also obtained by this methodology. Expansion capacities of nine hard and ten soft white wheats were measured by vacuum expansion. A good correlation (r2 = 0.99) was found between dough height and baked loaf height for this series. The results from these experiments suggest that the vacuum expansion test is a quick and reliable method for assessing the quality of flour, bake performance prediction, and new ingredient functionality in the dough formulations. Additional studies suggest that this instrument is equally effective for evaluation of pizza doughs. Experiments from pizza studies showed that this methodology could also be effectively applied to on-line process control and product development activities to improve processing time and reduce costs.; Factors influencing the gas cell structure of dough for breadmaking were studied. Quantitative measurements of the gas cell shape and size distribution were obtained with CrumbScan software. The effects of different variables on gas cell structure were investigated to help in understanding the reasons for variations in stability of dough structures. Results of this study showed that the differences in crumb grain features between different bread types could be distinguished and were significantly different (p < 0.05).