No abstract

No abstract

To explore the interaction between wheat starch and gluten, the thermomechanical, rheological properties, steamed bread quality of wheat flour, and gluten–starch doughs from different varieties were compared. Thermomechanical analysis showed that the stable time and gelatinization viscosity of model dough were higher than that of wheat dough. The results showed that R model dough (the ratio of starch/gluten is consistent with the original flour) had a higher stable time, strength, viscosity, stability, and extension properties than that of C model dough (the protein content is consistent with the original flour). Steamed bread prepared by model doughs exhibited higher hardness, gumminess, and chewiness. The internal structure of R dough steamed bread exhibited more tightly than that of C model dough steamed bread. Optimization of the starch/gluten ratios in wheat flour will be important for wheat breeding and controlling wheat processing aiming to better control the quality of steamed bread. Practical applications Wheat starch and protein are the two main components of wheat flour. Dough is a complex material with a high degree of elasticity and rheological properties of dough play an important role in end‐product quality. The processing of dough is the result of the interaction between starch and gluten, and the interaction affects the rheological properties of dough and ultimately the quality of products. In this study, two models of starch–gluten dough were established. First, starch–gluten ratio of dough was consistent with original wheat flour dough; second, the gluten content was consistent with the original dough. The rheological properties and the quality of steamed bread were compared between the original wheat flour dough and the model dough. The information obtained is expected to be important for wheat breeding and wheat dough processing aiming to broaden the application of wheat and wheat flour.

SummaryThe formula and preparation of steamed bread are different from those of western bread. The extensional rheological behaviour plays a key role in the development of steamed bread dough. However, there are inadequate studies on the rheological properties of mixed dough with yeast. In this study, the relationship between properties of dough in the presence or absence of yeast was elucidated. Besides, the flour characteristics and quality of steamed bread prepared from different wheat varieties were evaluated. The uniaxial/biaxial extensional rheological properties of wheat dough were compared with traditional rheological test results. Large deformations in the extensional properties were measured by Extensograph and the Kieffer extensibility rig, while the biaxial extension was quantified using uniaxial compression. These characteristics of dough and flour correlated with each other in different ways. Correlation analysis illustrated that the uniaxial extensional rheological properties of dough with yeast better indicated the quality of the steamed bread. Moreover, the total work for breakage of the dough with yeast was the best predictor for specific volume of steamed bread. The texture‐based properties of steamed bread showed correlation with biaxial extension viscosity. The rheological tests provide useful information for evaluating wheat flour and steamed bread quality.

During the production of steamed bread, fermentation is a critical step to obtain a final product with the desired characteristics. The quality of the final steamed bread is significantly affected by the properties of the dough. This study investigated the effects of fermentation on the rheological properties, state of water, microstructure of the dough, and the quality of steamed bread. After fermentation, the steamed bread dough exhibited higher stickiness, and was more easily to break during uniaxial extension. Biaxial extension tests revealed a significant decrease in biaxial extensional viscosity from 110,118 (0 min) to 11,544 Pa·S (80 min) at the strain rate of 0.04/S. The properties of the dough matrix were closely related to the fermentation time and the quality of the steamed bread is significant affected by the fermentation time. The results is valuable to provide theoretical basis for steamed bread making under precise control. Practical applications Fermentation is a key step in the production of steamed bread. This study (a) investigated the rheological properties of Chinese steamed bread dough during fermentation, including dough stickiness, uniaxial extensibility, and biaxial extension; (b) evaluated the effects of fermentation on the microstructure of fermented dough and steamed bread quality; and (c) investigated the relationship between the fermentation process and the quality of steamed bread. The information provided in this work will serve as the basis for further study on physical properties of fermented dough. The results is very valuable to provide theoretical basis for determining quality during the industrial production of steamed bread. This potentially leads to improved quality of steamed bread under precise control.

No abstract

The flood in small basin specializes in quick confluence, high peak value, hard to forecast and serious destruction effect, and once the flood disaster happens. It will put a great threat to the safety of the lives and properties of the resident alongside the river. Rational determination of design flood peak is crucial to the determination of scale, safety and benefit of the projects such as regulation of small basin, river renovation, danger eliminating and reinforcement of dangerous reservoirs and so on. Most of the small basins in China either lack gauged flood data or the catchment area of the project is quite different from the catchment area of the hydro-station, while the rainfall (metrological) data within this basin is relatively abundant. So, rational utilizing available gauged flood data to calculate the design flood of the project place whose catchment area is quite different from the hydro-station’s and utilizing available rainfall data to figure out the design flood are becoming particularly important. The rational method, (comprehensive) instantaneous unit hydrograph, hydrologic analogy, regional comprehensive method, experience formula and some other often-used methods which are often used in the flood calculation of small basin are systematically introduced in this paper. Taking Tingxi Basin in Fujian Province as an example, the above mentioned methods are applied and verified in the four places of Zaoshui hydro-station (10.5km2), Lower dam basin of Xiamen pumping storage power station (12.1km2), Wufeng hydro-station (50.1km2), and Tingxi Water Reservoir (100.8km2), the rationality of the results are analyzed, and the difference of those methods are compared in this paper. On the basis of these things, the application scope and condition of these methods are concluded, and a set of design flood calculation methods of small basin are relatively systematically summarized.

No abstract