Sensory aspects of astringency and changes of the oral environment in the mechanism of astringency.

Abstract

Astringency, a tactile sensation felt in the mouth after exposure to various foods, is not well understood. The underlying mechanism is not fully known, and it remains a challenging attribute to assess in sensory tests. Additionally, while most food astringency is caused by polyphenolic compounds, the cause of astringency in some other foods is not known. For the first part of my research, my objective was to improve the understanding of the mechanism of astringency by determining if it was related to a loss of saliva's ability to lubricate, the precipitation of specific classes of salivary proteins, or to the removal of oral lubricating films that coat the inside of the mouth. My results show that while astringency may be related to the latter, astringency is not related to a loss of salivary lubricity or the precipitation of any one class of salivary proteins. The second part of my research aimed to improve palate cleansing strategies for astringent foods. Palate cleansers are often used in an attempt to reduce build-up of astringency intensity that occurs over repeated exposures to astringent foods, but it is unknown how, or if, commonly used palate cleansers affect a person's sensitivity to astringency. Although I did not find that any of the cleansers were superior in their ability to limit the build-up of astringency intensity, it was clear that panelists were better able to discriminate among the astringency of various strength solutions when they used nothing or water to cleanse their palates. The aim of part III of my research was to determine the cause of astringency in acidic whey protein beverages. Although some believe that the whey proteins directly cause the astringency, there was reason to suspect that their high acid concentration was instead responsible. The results of my study found this to be true.