SENSORY FIRMNESS AND VISCOUSNESS Table III Discrimination Thresholds of Firmness and Viscousness of 80% and 90% Correct Judgements (Cream Base Substances) 487 Firmness Sample Group Discrimination Threshold (%) Sample P = 80% P = 90% Group Viscousness Discrimination Threshold (%) P • 80% P ---- 90% A 9.5 15.5 ,a 44.0 159.0 B 9.0 14.0 b 25.0 32.5 C 11.0 18.0 c 14.5 23.0 D 16.0 24.0 d 9.5 17.0 E 28.0 44.0 e 15.5 27.5 to 50 40 o "• 30 E o 20 10 " [3 ...... /lp = 90 %, •Ap= 80% i ! ! ..... 10 • 10 2 10 3 ]0 4 g / cm 2 Hardness Figure 4. Discrimination threshold for firmness of cream base substances in relation to hardness DISCUSSION AND CONCLUSIONS In the case of firmness, as is shown in Fig. 4, the tendency of becoming easy to discriminate as the hardness increased was noted however, extreme increase of hardness, such as seen in sample A, showed the reverse effect. Sample group B was the easiest to discriminate, that is, 80% of the panel

488 JOURNAL OF THE SOCIETY OF COSMETIC, CHEMISTS • 50 .c 40 ._E 20. .m_ C2 10 # d 0 101 10 2 10 3 1'04 cps Viscosity ,4p = 90 % Zip = 8O % Figure 5. Discrimination threshold for viscousness of cream base substances in relation to viscosity t- 'i, 50 ,40 30 20 10 ....... ZIp = 90% --,4p = 80% 0 10 • 10 2 lb 3 10 4 g/cftC Hardness Figure 6. Discrimination threshold for firmness of mechanical spring in relation to hard- ness