In 1995?Russian professor, Yu G. Vlasov proposed the concept of an electric tongue, which imitates a human tongue. In 2004, American scientists Richard Axel and Linda Buck won the Nobel Prize in Physiology or Medicine for their contribution to the understanding of how our olfactory system works.

Axel and Buck discovered about 1,000 different genes that form olfactory receptors to detect inhaled odorant molecules. Each receptor is highly specialized to detect a limited number of odorant substances. The receptor cells containing the receptors to send signals to the brain, where information from several olfactory receptors is combined, forming a pattern. Hence, we can recognize and remember smells.

In 2004, researchers in Japan and France launched a commercialized electric tongue. Deng carefully analyzed the theory, structure and application of it. While mainstream researchers focused on the sensory array, he shifted his focus to signal generation and responses to electric pulses. He used inert metallic electrodes, which made the sensor array easy to build. In the meanwhile, the system's stability and product life have also been optimized. The Smartongue is not only applied to analyze flavors but also to provide an overall assessment of food quality.

The Smartongue uses combinatorial pulse relaxation spectrum (CPRS) technology. This technology uses the action of a transient physical pulses, which produces not only a corresponding transient physical response but also a relaxation process. Relaxation refers to the process of the system returning to its original state after responding to stimulus.

According to the information posted on the website of the Sensory Science Laboratory at Zhejiang Gongshang University, "Different components in different systems show different relaxation behavior under the influence of the same transient physical pulses. Pulses can be implemented as different physical states by different techniques. By utilizing different types of physical pulse and their composition, the specific comprehensive information about a system can be acquired. That leads to CPRS, a new scientific thought and technical method for intelligent analysis. The most outstanding feature of CPRS is that by regarding the single pulse relaxation curve as the elementary mode, CPRS can be flexibly designed to give out various combinatorial pulse spectrums based on the elementary parameters."

Similar to the biological mechanism, Smartongue has sensors to generate electric signals, which are combined and analyzed. Each sensor can sense a group of chemical substances.

"With CPRS technology the Smartongue has wide application and can swiftly test solutions or powders, aqueous solutions or organic solutions," Deng said. "A sample can be tested in one to three minutes, whereas it usually takes other electric tongues six to eight minutes to test a sample. The Smartongue also features abundant information, high resolution and a convenient cleaning process, which takes only one to two minutes."

It has been used in companies producing food and alcoholic drinks as well as by government departments responsible for quality appraisal.