SUPERPOSITION OF COMPLEX VISCOSITY CURVES DURING GELATINIZATION OF STARCH DISPERSION AND DOUGH

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1 Corresponding author. Phone: 315-787-2266; Fax:315-787-2397/2284; e-mail: mar2@cornell.edu

ABSTRACT

Complex viscosity (η*) of 8% tapioca starch dispersion (STD) during gelatinization at a specific oscillatory frequency (ω, rad s−1) was independent of the heating rates: 1.5 to 6.0C min−1 when plotted against temperature as the independent variable instead of time. The influence of ω in the range: 3.14 to 62.83 rad s−1 on η* was scaled by a frequency shift factor resulting in a reduced complex viscosity (η*R) versus temperature (58–88C) master curve. Similar η*R versus temperature master curves were derived for η* data on a 8% waxy rice STD at the heating rate 2C min−1 and ω values 1.27 to 125.6 rad s−1, and a 45.5% waxy rice dough at the heating rate 4C min−1 and ω values 1.27 to 94.2 rad s−1. The areas under the η*, at ω=6.28 rad s−1, versus temperature curves of the tapioca and the waxy rice STDs with different starch concentrations were exponentially related to the concentrations.

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