The static and dynamic rheological properties of doughs made from six rice and high-gluten wheat flour blends were studied. In the dynamic rheological frequency sweep test, the storage modulus (G’) and loss modulus (G’’) of mixed doughs showed an overall upward trend with increasing amount of rice flour added, and the opposite trend was observed for tan δ. In the creep relaxation test, the maximum creep strain, maximum creep compliance and instantaneous recovery compliance gradually decreased, and the zero shear viscosity and instantaneous recovery ratio gradually increased. These observations indicated that the gluten in wheat flour was diluted after adding rice flour, but the starch granules in rice flour swelled and adhered to each other after absorbing water, and interacted with rice flour proteins, imparting higher elastic modulus and more internal structure to dough. In the dynamic rheological temperature sweep test, the viscoelasticity of mixed doughs was changed significantly before and after the gelatinization temperature, and the G’ and G’’ curves were similar to the starch gelatinization curve, indicating that starch was the major component affecting the rheological properties of raw dough during heating. The G’ and G’’ increased regularly in the high temperature zone, but decreased regularly in the low temperature zone below 60 ℃ during cooling. The samples had solid-like properties during the whole cooling process.

This study was executed in order to further improve the emulsion stability of chitosan/gum arabic composite particles and to regulate the rheological properties of high internal phase emulsions stabilized by it. Chitosan/gum arabic composite particles were prepared by different treatments and were used to stabilize high internal phase emulsions. The effects of the structure and properties of the particles on the structure, rheological properties and stability of high internal phase emulsions were explored. The results showed that compared with the control group (pH 5.0), ultrasonic and heat treatments significantly increased the yield of composite particles. There was no significant difference in the particle size or stability of the high internal phase emulsions stabilized by the treated and control composite particles, while the oil binding capacity and viscoelasticity were significantly improved. pH increase to 7.0 and sodium tripolyphosphate crosslinking had a negative effect on the yield of particles, making the composite particles exhibit poor emulsion stability and oil binding ability. The above findings showed that ultrasonic and heat treatments could improve the stability and adjust the rheological properties of chitosan/gum arabic composite particle-stabilized high internal phase emulsion, which shows potential in food texture regulation and fat substitutes with different textures.

The relationships between chemical composition, structure and physicochemical properties such as pasting, thermal, and textural properties of 12 temperate rice cultivars grown in Heilongjiang Province, China were investigated in this study. There were significant differences in the content of fat, protein, ash, amylose, damaged starch among 12 cultivars. Brabender Viscograph results showed that gelatinization time, peak viscosity, pasting and peak temperature ranged from 9 min to 15 min, 2100 BU to 2500 BU, 58.75 ℃ to 72.00 ℃ and 63.75 ℃ to 84.45 ℃, respectively, except for the waxy one Longjing 9. T_o, T_p, T_c and ΔH were found in the range of 58.34 ℃ to 67.96 ℃, 65.39 ℃ to 75.38 ℃, 78.47 ℃ to 90.69 ℃ and 2.036 J/g to 3.127 J/g respectively. Scanning Electron Micro-photograph results showed that all starch granules were polyhedral with irregular shapes, except Longjing 9 showing signs of the loss of physical integrity. The hardness, adhesiveness, springiness, gumminess, cohesiveness and resilience ranged from 395.87 g to 1161.76 g, -90.842 g·mm to -36.4 g·mm, 0.498 to 0.747, 78.631 g to 466.837 g, 0.199 to 0.569, 0.321 to 0.504, respectively. Correlation studies indicated that amylose, damaged starch, protein, fat and ash played a more important role in determining the rice properties of pasting, thermal, crystallinity and texture.