Model rva 4

The pasting properties of NBF-gum mixtures (7% w/w) were measured on a Rapid Visco Analyser (RVA) (Model RVA-4, Newport Scientific PTY Ltd., Warriewood, Australia). All NBF-gum mixture dispersions (5% w/w) containing 0, 0.3, and 0.6% (weight basis) gum concentrations were prepared, as previously described. The dispersions (28 g) were then poured into aluminum canisters and stirred manually using a plastic paddle for 20~30 s prior to insertion into the RVA machine. The heating and cooling cycles were programmed in the following manner. All samples were held at 50°C for 1 min, and then heated to 95°C at a rate of 7.5°C/min and held at 95°C for 5 min, cooled to 50°C at a rate of 7.5°C/min, and finally held at 50°C for 5 min, while maintaining a rotation speed of 160 rpm. Then, the peak viscosity (maximum viscosity during pasting), breakdown viscosity (the difference between the peak viscosity and the minimum viscosity during pasting), setback viscosity (the difference between the maximum viscosity during cooling and the minimum viscosity during pasting), final viscosity (the viscosity at the end of the RVA run), and pasting temperature (temperature indicating an initial increase in viscosity) of the NBF-gum mixture dispersions were determined.