Abstract: Rheology is important to the manufacturing of cereal-based food products. With the use of dynamic rheometer, the research was aimed at rheological properties of wheat flour-water dough containing California almond flour and alpha-amylase. The change of visco-elastic modulus (G″and G′) of dough was investigated for doughs containing 0%, 12.5%, 25%, 37.5% and 50% California almond flours, respectively, with frequency and temperature changing. The effect of different almond flour content on dough G″and G′at same frequency and temperature points was compared. The effect of alpha-amylase on G″ and G′of dough containing 0%, 50% full-fat and 50% fat-free almond flours were also determined. Results showed: (1) that almond flour content significantly affect dough G″and G′, and that G″value of dough containing full-fat almond flour is larger than that of dough containing fat-free almond flour. But the value of G′was greater for dough containing fat-free almond flour, which suggested that lipid in almond flour played a role; (2) that when frequency is same, G″and G′of wheat flour dough is larger than those of doughs containing 12.5% and 25% almond flour (full-fat or fat-free) and less than those of dough containing 37.5% and 50% almond flour. This could be caused by the interactions of almond and wheat proteins; (3) that when the temperature of the dough was increased, the value of G″and G′of doughs decreased with increased almond flour content; when the tempera- ture of the dough was decreased, G′value decreased with increased almond flour content. The G′value for dough containing fat-free almond flour was greater than that for full-fat almond flour dough, while the effect of almond flour on dough G″value was found to be insignificant with decreased temperature; (4) that the G″and G′values of doughs all went down after alpha- amylase addition. An understanding of the fundamental aspect of dough rheology could contribute significantly to improved formulation, greater success in processing, increased productivity in manufacturing, and higher quality products of cereal-based foods.

Key words: dough system, California almond flour, visco-elastic modulus, alpha-amylase, rheology