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This study aimed to investigate the impact of heat treatment on the molecular structure of starch and protein in wheat flour and to establish a correlation between the changes in molecular structure and the resulting effects on the pasting properties of the flour. Heat treatment increased the pasting viscosity and pasting temperature with the extent of heat-treated time and temperature. Moreover, the water absorption indexes, swelling power, and gelatinization enthalpy of heat-treated flour were higher than that of untreated flour, while the water solubility indexes were lower. The clustered starch granules and aggregated protein increased the particle size of flour after heat treatment. Additionally, heat treatment decreased the damaged starch content from 6.54% in native flour to 2.94% in treated flour (100 °C, 30 min), causing an increase in the short-range order structure and relative crystallinity of starch. The aggregated protein induced by heat owned the lower free sulfhydryl content and higher SDS-insoluble protein and β-sheet structure. The pasting properties variations were mainly correlated with the molecular structure changes of protein induced by heat. These results provided a theoretical basis for tailoring flour to produce wheat-based products with desired properties through the application of heat treatment technology. [Display omitted] • Heat treatment increased the pasting viscosity and pasting temperature of wheat flour. • Heat treatment induced the protein aggregation of wheat flour. • Heat treatment increased the crystallinity and short-range order structure of wheat flour. • The high viscosity in heat treated flour mainly related with the structural changes in protein. [ABSTRACT FROM AUTHOR]

The effect of superheated steam treatment on the physicochemical properties of wheat flour and quality characteristics of cake were investigated. Superheated steam treatment significantly increased the swelling power, viscosities and gelatinization temperature, but reduced the gelatinization enthalpy (p < 0.05), compared with native wheat flour. However, the dough made from the treated flour was harder to form. Moreover, superheated steam treatment significantly increased the value of falling number. Cake quality was affected by the changes in the physicochemical properties of wheat flour. Results showed that superheated steam treatment significantly decreased the hardness of cake from 1465 g (native flour) to 377 g (150 °C, 1 min), and increased the specific volume of cake from 3.12 mL/g (native flour) to 3.9 mL/g (150 °C, 1 min). The present study suggests that superheated steam treatment has great potential as a flour modification technology for cake quality improvement. • Physicochemical properties of wheat flour treated with superheated steam were studied. • Superheated steam treatment weakened the gluten strength of dough. • Superheated steam treatment promoted the functional properties of wheat flour. • Wheat flour superheated steam treatment could improve cake quality characteristics. [ABSTRACT FROM AUTHOR]

Flavourzyme is a commercial peptidase, mainly with exopeptidase activity. In this study, effects of Flavourzyme addition (0–0.16 g/100 g) on properties of wheat dough and bread were systematically studied. Bread with a low concentration (0.01–0.08 g/100 g) of Flavourzyme addition had a large specific volume and soft texture with a uniform cell structure. The optimal Flavourzyme content was 0.04 g/100 g and the specific volume increased from 3.9 mL/g to 4.4 mL/g, the hardness decreased from 21.7 N to 13.3 N. The gas production capacity of yeast increased with low concentrations of Flavourzyme addition, promoting dough expansion. Flavourzyme had a clear hydrolysis effect on wheat gluten in dough and caused the depolymerization and unfolding of gluten structure, thus decreasing the strength and viscoelasticity of dough. Confocal laser scanning microscopy and scanning electron microscopy results further revealed that a low concentration of Flavourzyme had a slight effect on gluten. However, the gluten structure became discontinuous and open, which made the dough easily collapsed during fermentation, resulting in poor bread quality with high Flavourzyme content. The positive effects of appropriate amount of Flavourzyme addition on dough and bread properties indicated the potential of Flavourzyme as a bread improver by substituting chemical additives. • Moderate amount of Flavourzyme addition improved the quality of bread significantly. • The optimal addition of Flavourzyme is 0.04 g/100 g (based on wheat flour). • Dough expansion was enhanced with moderate Flavourzyme addition. • Moderate Flavourzyme addition did not cause obvious damage to gluten network. [ABSTRACT FROM AUTHOR]