Abstract: The effect of Spirulina powder on the rheological properties, microstructure and gluten properties of wheat flour dough was investigated. The results showed that in terms of mixograph characteristics, the addition of Spirulina powder generally increased the water absorption rate, development time and peak curve area of dough, and increased the energy required to form dough. Adding a small amount of Spirulina powder enhanced the strength and reduced the viscosity of dough, but the kneading resistance became weaker at higher concentrations of added Spirulina powder. After adding Spirulina powder, the breaking force of dough gradually increased and the breaking distance decreased. Meanwhile, the free sulfhydryl content increased and the disulfide bond content decreased. When the amount of added Spirulina powder was more than 6%, the wet gluten content decreased significantly, and the micrograph showed that the gluten network was seriously damaged. Polyacrylamide gel electrophoresis (PAGE) showed that the proportion of high-molecular-mass glutenin decreased and the proportion of low-molecular-weight glutenin increased after adding Spirulina powder. The results of Fourier transform infrared (FT-IR) spectroscopy showed that the addition of Spirulina powder reduced the content of ordered structure and increased the content of disordered structure in gluten proteins. Therefore, it is speculated that when a small amount of Spirulina powder is added to dough, dietary fiber in Spirulina fills the gluten network in dough after absorbing water, strengthening the adhesive state of the gluten protein network and improving dough strength. However, when the amount of added Spirulina powder is higher than 6%, the cross-linking of gluten proteins is hindered, thereby weakening gluten, reducing the ordered structure content of gluten proteins, and ultimately deteriorating the rheological properties of dough.

Key words: Spirulina powder; dough; rheological properties; gluten; microstructure