RELATIONSHIPS BETWEEN SENSORY VISCOSITY AND APPARENT VISCOSITY OF CORN STARCH PASTES

Sensory viscosity and apparent viscosity of corn starch pastes were st udied at 15 degrees, 25 degrees, 37 degrees and 50C, within the concen tration range 0.9%-6.2%. The oral and visual sensory viscosity estimat ions were obtained by the converging limits method, a modified version of magnitude estimation. The exponents (perceptual growth rate) were similar (0.40 oral and 0.41 visual). No significant differences were d etected between the two evaluations. Visual stimulation yielded result s with a lower deviation, suggesting that this type of judgment is eas ier for the subject. The consistency of results obtained by the conver ging limits was determined by comparison of the viscosity of starch pa stes with silicone oil by cross-modality matching. The ratio upper/low er limit of physical range used (13/0.03 for corn starch similar to 11 00/1.80 for silicone oil) is approximately the same for both substance s. This is also shown by the fact that the slope of the log-log functi on relating them equals 1.11 +/- 0.21. No significant effect of temper ature was observed on the oral viscosity estimates. The effective rang e of sensory viscosity for corn starch pastes was between 340 and 1300 cP.