Oral astringency: effect of ageing and role of saliva

Oral astringency is an important sensory characteristic of food and beverages containing polyphenols. However, while polyphenols enriched diet are recommended especially for elderly, astringency perception in elderly people is not documented. The aim of the present work was to evaluate sensitivity to astringency in function of age and saliva (flow and composition). Fifty-four panellists including 30 elderly people (age=75±4.2) and 24 young people (age=29.4±3.8) participated in this study. Astringency was evaluated by 2-Alternative Forced Choice procedure using four tannic acid solutions (from 0.02 g/l to 0.574 g/l). Whole unstimulated saliva was collected for 5 min before and after sensory tests. Each 2-AFC test was done 3 times and evaluation was performed 3 times in three different sessions. Results showed that there was a significant difference in astringency threshold between young group and elderly group (elderly=0.41 g/l ± 0.23, young=0.29g/l ± 0.26; p=0.011). There were no significant differences in unstimulated salivary flow either at the beginning (p=0.56) or the end (p=0.1) of the session between young and elderly. Moreover, correlation between unstimulated salivary flow and threshold was significant only for young group (r=-0.44, p=0.029)