CAHNRS > WSU Sensory Science Center > Our Services > Volatile, Electronic Tongue (e-tongue) and General Analysis

Analytical Capabilities

instrument for food analysis; gas chromatograph.

Volatile analysis

For the analysis of flavors and aromas (volatile compounds), we have one gas chromatography/olfactometer/mass spectrometer. This system is compatible with solid-phase microextraction (SPME), solid-phase dynamic extraction, and liquid injection. We also have a gas chromatograph equipped with stir bar sorptive extraction capabilities.

Electronic Tongue (e-tongue)

The electronic tongue (e-tongue) is an analytical instrument that quantifies a sample’s non-volatile organic and inorganic compounds. It draws on the underlying principle of the neurophysiology of the sense of taste to provide a “taste fingerprint” based on the nonvolatile profile of the product.

The e-tongue that we have in the lab has seven membrane-coated sensors with an integrated pattern recognition system. In a typical operation of the electronic tongue, the sensors interact with the electrical properties of the analytes in the solution and provide responses characteristic of the solution being assessed. The use of multivariate and regression analysis confers separation and prediction capabilities, respectively.

Foods

We have used the e-tongue to distinguish among different sweeteners and then determine relationships between sensory evaluation and the e-tongue response. We found a strong correlation between the e-tongue and the consumer response to the perceived better and metallic attributes in the sweeteners. We have also developed e-tongue methodology to determine differences among the composition of various foods, including cheese, granola bars, protein beverages and egg products.

Beverages

We have used the e-tongue to distinguish among wines made with different wine processing techniques, finding a strong relationship between the e-tongue response and sensory evaluation of bitterness, sweetness, and sourness, as well as with the mouthfeel attributes of ethanol and astringency. We have used the e-tongue to distinguish among faulted red and white wines. Other beverages in which we have used the e-tongue include beer and apple cider.

Pharmaceuticals

Because of the difficulty in using sensory panels to profile pharmaceuticals, the e-tongue has been useful in profiling newly developed pharmaceuticals. The active ingredients in pharmaceuticals often confer problematic bitter or metallic notes. The use of the e-tongue for the detection of bitter and metallic properties has been particularly useful in assessing pharmaceuticals that are being developed for children, as well as pharmaceuticals that are being formulated to mask the active ingredient. These newly developed pharmaceuticals can then compared to those already available on the market.

researcher conducting texture analysis on cheddar cheese.

Physical Structure

Our lab has a brand new Texture Profile Analyzer (TPA) to assess physical parameters of foods; these parameters can then be correlated to food texture properties assessed through sensory evaluation. The TPA utilizes a double compression test that will generate a force/time curve that will be utilized to assess physical parameters such as hardness, cohesiveness, springiness, adhesiveness, fracturability, chewiness, and gumminess.

General Analysis

Our lab also has the capability to assess titratable acidity, pH, and sodium (via ion selective electrode). Within our department, we have access to high-performance liquid chromatography (HPLC) for further characterization of non-volatile compounds in foods and beverages.