Accurate Measurement of Pasting Temperature by the Rapid Visco-Analyser: a Case Study Using Rice Flour

Pasting properties are among the most important characteristics of starch, determining its applications in food processing and other industries. Pasting temperature derived from the Rapid Visco-analyser (RVA) (Newport Scientific), in most cases, is overestimated by the Thermocline for Windows software program. Here, two methods facilitating accurate measurement of pasting temperature by RVA were described. One is to change parameter setting to 'screen' the true point where the pasting viscosity begins to increase, the other is to manually record the time (T1) when the pasting viscosity begins to increase and calculate the pasting temperature with the formula of (45/3.8) x(T1-1)+ 50 for rice flour. The latter method gave a manually determined pasting temperature which was significantly correlated with the gelatinization temperature measured by differential scanning calorimetry.