The instrumental apparent viscosity measurements for the RF sample gave a value of 87.2 mPa at 30°C at a shear rate of 29.3 s−1. This value is significantly lower than the L sample but higher than the ice cream samples of lower fat levels. Interestingly, the values for the L sample is similar to that obtained by Goff et al. (1994) of 130 mPa at 20 s−1 and 30°C for a regular fat formulation. The lower apparent viscosities seen for the LF and FF samples (Table 7) were similar to those detected by the trained panelists and there was a correlation between sensory and instrumentally determined apparent viscosity (Table 6). Apparent viscosity was also correlated with the mouthcoating.
In the work of Specter and Setser (1994), the highest mix viscosity was associated with the regular fat control sample (66.7 mPa) with the lowest viscosity occurring for the fat free sample (33.8 mPa) made with 12% N-oil® gel. Three of the four fat free ice creams evaluated by Ohmes et al. (1998) had measured mix viscosities in the range of 24.5–38 mPa s−1 and these values are similar to values determined for FF and LF. Despite these similarities, the viscosity of the light sample in the sutdy of Ohmes et al. was lower than that for the fat free ice creams whereas the opposite was observed during this study (Table 7). The higher apparent viscosity values for the light samples attained in this study suggests the inclusion of a modified starch can at least partially overcome the decrease in viscosity normally associated with fat reduced samples.