| The rheological properties of non-developed (by the ice powder procedure), partially developed (by rheometer with shear or extensional deformation), and developed doughs (by farinograph) have been investigated and these four doughs represent different levels of dough development. To understand the relationship between gluten proteins and dough rheology, this study used (1) a rheometer and laser scanning confocal microscope (LSCM) to study the relationships between rheological properties and ultrastructural characteristics of these four types of doughs; (2) disulfide-sulfhydryl analyses, gel filtration chromatography, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), acid polyacrylamide gel electrophoresis (A-PAGE), and densitometry to investigate proteins in the four types of doughs mentioned and relate protein properties to dough rheology; and (3) two one-stage fermentation procedures (ice powder ingredients without the use of a mixer or normal ingredients with the use of a mixer) to make crackers and compare quality attributes of these crackers.;Rheological data revealed that developed dough had the highest G* (most elastic), followed by doughs partially developed with extensional deformation and then shear deformation, and finally by non-developed dough. The LSCM z-sectioning (scanning of different layers of the sample) and the analysis of amount of protein matrix showed that developed dough had the most protein matrix, and non-developed dough had the least. It also showed the higher the G*, the more the protein network.;Free sulfhydryl content was the lowest in native flour and non-developed dough, and the highest in partially developed doughs, while a reverse trend was observed for disulfide content. The protein elution profiles from gel filtration chromatography among same flour samples shifted with levels of dough development. With respect to the smallest sized protein molecules, native flour had the most, followed by non-developed, partially developed, and then developed doughs. SDS-PAGE and A-PAGE exhibited similar protein patterns among the same protein fractions of each native flour and its different doughs. Densitometric data showed that the amount of high molecular weight (HMW) glutenins increased and the amounts of low molecular weight glutenins, gliadins, and albumins/globulins decreased with progressive levels of dough development. Results also indicated that the increase in both size and amount of HMW glutenins is related to the strength of dough and the amount of protein matrix present in the dough.;Based on the one-stage fermentation procedures to make crackers, it was found that the overall qualities (i.e., weight, moisture, length, width, thickness, volume, and peak breaking force) of baked normal and ice powder crackers could distinguish among all flour samples. The overall qualities of baked normal and ice powder crackers made from the same flour showed similar trends. Baked ice powder crackers had higher weight, moisture, and peak breaking force than normal crackers, whereas they had less shrinkage and were lower in thickness and volume. As demonstrated by this study, the ice powder technique has the potential for producing acceptable crackers. |
