ORAL ASTRINGENCY - A TACTILE COMPONENT OF FLAVOR

The psychophysical, chemical and physiological bases of the oral sensa tion of astringency are discussed in an effort to clarify the nature o f this enigmatic sensation. It is argued that, despite recent data fro m animal studies that suggest it is a taste sensation mediated by the chorda tympani nerve, astringency arises primarily from increases in f riction between mucosal surfaces. Evidence is discussed that supports the view that oral astringency results primarily from the precipitatio n of salivary, mucoproteins, which impairs the natural lubrication of oral surfaces. The ensuing rise in friction induces sensations of dryn ess and roughness which, although subtle at first, can grow in magnitu de over repeated exposures. These changes in the surface texture of th e mouth are an important component of the 'flavor' of common foods and beverages such as fruits, nuts, teas and coffee.