Research advances on the astringency mechanism and its regulation based on macromolecular interactions with salivary proteins using tribology

Astringency is one of the most complex sensations originating from the interaction between foods containing astringency substances (such as polyphenols) and salivary proteins. Despite being considered as a tactile response, the specific physical processes responsible for astringency and sub-qualities remain controversial. “Tribology” conducted in a simulated oral environment is a potential method for quantifying astringency. The article systematically reviews the technique of oral tribology used to study and understand astringency, including the instrumentation, influencing factors, and its correlations established so far with both the total astringency and sub-qualities. The methods of regulating astringency, especially from the tribological perspective, have also been discussed. Oral tribology can provide important information for astringency, including mechanism understanding, sub-qualities differentiation, and astringency prevention, demonstrated by the quantitative or qualitative correlations established. However, it still requires further innovation and development, including simulating real oral conditions and the sequence of events at each stage of astringency perception development with the combination of analyses by multiple technologies. The recently proposed hypothesis of the coexistence of friction and the molecular mechanism is a promising one of astringency perception. And the most promising approach for reducing astringency appears to be the utilization of polysaccharides, although further exploration is required.