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RESEARCH PRODUCT

Salivary properties involved in astringency sensitivity in human differ as a function of age

subject

description

Astringency is an important sensory characteristic of foods and beverages containing polyphenols. However, astringency perception in elderly people is not documented. Current hypothesis on astringency mechanism involved aggregation of the mucosal pellicle by tannins and its protective role by salivary proteins in particular proline rich-proteins (PRPs). The aim of the present work was to evaluate sensitivity to astringency in function of age and saliva (flow and composition). Fifty-four panelists including (30 elderlies and 24 young) participated in this study. Astringency was evaluated by 2-Alternative Forced Choice procedure. For salivary PRPs, a western blot methodology was set up to evaluate specifically glycosylated (gPRPs) and basic PRPs (bPRPs). Results showed that the astringency threshold was significantly higher in the elderlies compared to the young group.A negative correlation between salivary flow and threshold value was observed in the young group only. When it comes to PRP amounts, the results showed that there was no difference between young and elderlies regarding g- and bPRP levels. However, a negative correlation between bPRPs levels and astringency threshold was observed in elderly group while a positive correlation was observed for gPRPs level in the young group. This is the first study describing a difference in oral astringency perception between young and elderly subjects related to respective salivary properties. Salivary PRP amounts should explain this difference but only at the group scale. These results suggest that different mechanisms occur in astringency sensitivity as a function of age. Further analysis considering other salivary tannin binding proteins should be performed in the future in order to decipher these mechanisms in both populations.