Robotic ‘tongue’ tipped to cut beer fraud
Lead author Manel del Valle told this website that the Cetó et al. study published last May in Food Chemistry was based on “very preliminary research” and said results had since hit 96%.
Del Valle and his colleagues, from the Chemistry department at the Universitat Autònoma de Barcelona, believe that ‘robots’ with a sense of taste could one day supplant human food tasters.
For last year’s study, the scientists used an electronic tongue with 21 ion-selective polyvinyl chloride electrodes to test various store bought beers – Moritz, pictured, was one of the drinks tested – with two different pattern recognition methods used to correctly identify 81.9% of samples.
De Valle said that ‘supervised learning’ and linear discriminant analysis allowed the electronic tongue to distinguish between main categories of beer studied – Schwarzbier, lager, double malt, Pilsen, Alsatian and low alcohol.
Potential in the wine world
Last Friday, Del Valle told this website that variations of the team’s ‘electronic tongue’ would also be useful to defeat food fraud beyond beer, and promised more details in future published studies.
“The improvements [since the published study] meant new sensors, from a different family (voltammetric) and much better statistically planned and controlled experiments,” he said.
“We have already done a fantastic study to prove if a Cava sparkling wine is vintage or not, which is useful against possible fraud – the price of the two are quite different,” he said.
Introducing the May 2013 study, Cetó et al. explain that water pre-treatment is an important first step in brewing that helps unify quality, improve beer flavor and style, since different ions in the water affect what type of beer is obtained.
New beer classification system
“Given the importance of ionic concentration of water, measuring their concentration in beer samples would be a good way to develop a new classification system,” they write.
“Unfortunately, there are few optimally operating chemical sensors that may function without any interference or matrix effect,” Cetó et al. add.
Cetó et al. explain that the pH of water can be modified by three different compounds – bicarbonate increases it and calcium or magnesium salts decrease it.
But carbonate and bicarbonate – expressed as ‘total alkalinity’ – are considered the most crucial factors in water given how they affect maceration, the scientists write. For example, high levels in Munich waters are responsible for the mildness of that city’s dunkel beers.
“The sodium ion contributes to beer body and character, while chloride highlights malt sweetness, although high levels of these two will leave a seawater taste,” the authors write.
Title: ‘Beer classification by means of a potentiometric electronic tongue’
Authors: Cetó, X., Gutiérrez-Capitán, Calvo, D., Del Valle, Manel.
Source : Food Chemistry, available online May 23 2013, http://dx.doi.org/10.1016/j.foodchem.2013.05.091
