A saliva molecular imprinted localized surface plasmon resonance biosensor for wine astringency estimation

- New technology to understanding the interactions of polyphenols and complex protein matrices was proposed.
- Mimic global interactions of wine polyphenols and saliva matrix applied to wine astringency.
- The sensor response correlates well to astringency by sensorial analysis.
- Showed that astringency could not be evaluated based on analysis of individual polyphenols.
- Insight into the role of individual polyphenols in the context of wine astringency.

Wine astringency was evaluated based on the interaction of two complex matrices (red wine and saliva) by combining localized surface plasmon resonance (LSPR) and molecular imprinted polymers (MIP) at gold nanodisks as an alternative to sensorial analysis. The main objective of the work was to simulate wine astringency inside the mouth by mimicking this biological system. The LSPR/MIP sensor provided a linear response for astringency expressed in pentagalloyl glucose (PGG) units in concentrations ranging from 1 to 140 μmol/L. The sensor was also applied to wine samples correlating well with sensorial analysis obtained by a trained panel. The correlation of astringency and wine composition was also evaluated showing that anthocyanins may have an important role, not only for pigmentation but also in astringency.