Electronic equivalent to human tongue
reliable taste measurements for companies currently relying on
human tasters for their quality control of foods.
A new hand-held electronic tongue aims to provide accurate and reliable taste measurements for companies currently relying on human tasters for their quality control of foods.
According to a report in the science journal 'Nature' the device made by Antonio Riul of EMBRAPA Instrumentação Agropecuária in São Carlos, Brazil(1), and colleagues rivals human taste buds and never tires.
The electronic tongue can sense low levels of impurities in water. It can discriminate between Cabernet Sauvignons of the same year from two different wineries, and between those from the same winery but different years. It can also spot molecules such as sugar and salt at concentrations too low for human detection.
The report continues that details of this new system are still not understood however each taste sensation may correspond to a fingerprint signal induced by the differential activation of the various taste receptors.
It contains four different chemical sensors. The sensors comprise very thin films of three polymers and a small molecule containing ruthenium ions. These materials are deposited onto gold electrodes hooked up to an electrical circuit.
In a solution of flavoursome substances such as sugar, salt quinine (bitter) and hydrochloric acid (sour), the thin sensing films absorb the dissolved substances. This alters the electrical behaviour (the capacitance) of the electrodes in a measurable way.
Each sensor responds differently to different tastes. A composite sensor that incorporates all four therefore produces an electronic fingerprint of the taste. The researchers combine these responses into a single data point on a graph. The position on the graph reflects the type of taste: sweet lies towards the top left, for example, sour towards the top right.
