Electronic tongue
Encyclopedia
The electronic tongue is an instrument that measures and compares tastes.
Chemical compound
s responsible for taste are perceived by human taste receptors, and the seven sensors of electronic instruments detect the same dissolved organic and inorganic compound
s. Like human receptors, each sensor has a spectrum of reactions different from the other. The information given by each sensor is complementary and the combination of all sensors results generates a unique fingerprint. Most of the detection thresholds of sensors are similar or better than those of human receptors.
In the biological mechanism, taste signals are transducted by nerves in the brain into electric signals. E-tongue sensors process is similar: they generate electric signals as potentiometric variations.
Taste quality perception and recognition is based on building or recognition of activated sensory nerve
patterns by the brain and on the taste fingerprint of the product. This step is achieved by the e-tongue’s statistical software which interprets the sensor data into taste patterns.
and sensors are dipped in a beaker containing a test solution for 120 seconds. A potentiometric difference between each sensor and a reference electrode is measured and recorded by the E-Tongue software. These data represent the input for mathematical treatment that will deliver results.
, food and beverage sector, etc.
It can be used to:
system. The result is the detection of the tastes that compose the human palate. The types of taste that is generated is divided into five categories sourness, saltiness, bitterness, sweetness, and umami (deliciousness). Sourness, which includes HCl, acetic acid
, and citric acid
is created by hydrogen ions
.Saltiness is registered as NaCl, sweetness by sugars, bitterness, which includes chemicals such as quinine and caffeine is detected through MgCl(2), and umami by monosodium glumate from seaweed, disodium in meat/fish/mushrooms.
Chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
s responsible for taste are perceived by human taste receptors, and the seven sensors of electronic instruments detect the same dissolved organic and inorganic compound
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
s. Like human receptors, each sensor has a spectrum of reactions different from the other. The information given by each sensor is complementary and the combination of all sensors results generates a unique fingerprint. Most of the detection thresholds of sensors are similar or better than those of human receptors.
In the biological mechanism, taste signals are transducted by nerves in the brain into electric signals. E-tongue sensors process is similar: they generate electric signals as potentiometric variations.
Taste quality perception and recognition is based on building or recognition of activated sensory nerve
Sensory neuron
Sensory neurons are typically classified as the neurons responsible for converting external stimuli from the environment into internal stimuli. They are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord...
patterns by the brain and on the taste fingerprint of the product. This step is achieved by the e-tongue’s statistical software which interprets the sensor data into taste patterns.
Operation
Liquid samples are directly analyzed without any preparation, whereas solids require a preliminary dissolution before measurement. Reference electrodeReference electrode
A reference electrode is an electrode which has a stable and well-known electrode potential. The high stability of the electrode potential is usually reached by employing a redox system with constant concentrations of each participants of the redox reaction.There are many ways reference...
and sensors are dipped in a beaker containing a test solution for 120 seconds. A potentiometric difference between each sensor and a reference electrode is measured and recorded by the E-Tongue software. These data represent the input for mathematical treatment that will deliver results.
Range of applications
Electronic Tongues have several applications in various industrial areas: the pharmaceutical industryPharmaceutical company
The pharmaceutical industry develops, produces, and markets drugs licensed for use as medications. Pharmaceutical companies are allowed to deal in generic and/or brand medications and medical devices...
, food and beverage sector, etc.
It can be used to:
- analyze flavor ageing in beverages (for instance fruit juiceJuiceJuice is the liquid that is naturally contained in fruit or vegetable tissue.Juice is prepared by mechanically squeezing or macerating fruit or vegetable flesh without the application of heat or solvents. For example, orange juice is the liquid extract of the fruit of the orange tree...
, alcoholic or non alcoholic drinksAlcoholic beverageAn alcoholic beverage is a drink containing ethanol, commonly known as alcohol. Alcoholic beverages are divided into three general classes: beers, wines, and spirits. They are legally consumed in most countries, and over 100 countries have laws regulating their production, sale, and consumption...
, flavored milks…) - quantify bitterness or “spicy level” of drinks or dissolved compounds (e.g. bitterness measurement and prediction of teas)
- quantify taste masking efficiency of formulations (tablets, syrups, powders, capsules, lozenges…)
- analyze medicines stability in terms of taste
- benchmark target products.
Artificial Taste
The electronic tongue uses taste sensors to receive information from chemicals on the tongue and send it to a pattern recognitionPattern recognition
In machine learning, pattern recognition is the assignment of some sort of output value to a given input value , according to some specific algorithm. An example of pattern recognition is classification, which attempts to assign each input value to one of a given set of classes...
system. The result is the detection of the tastes that compose the human palate. The types of taste that is generated is divided into five categories sourness, saltiness, bitterness, sweetness, and umami (deliciousness). Sourness, which includes HCl, acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
, and citric acid
Citric acid
Citric acid is a weak organic acid. It is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks...
is created by hydrogen ions
Hydronium
In chemistry, a hydronium ion is the cation , a type of oxonium ion produced by protonation of water. This cation is often used to represent the nature of the proton in aqueous solution, where the proton is highly solvated...
.Saltiness is registered as NaCl, sweetness by sugars, bitterness, which includes chemicals such as quinine and caffeine is detected through MgCl(2), and umami by monosodium glumate from seaweed, disodium in meat/fish/mushrooms.