Mini-electronic Tongue Used to Discriminate between Coffee Samples of Different Geographical Origin

Abstract

This paper presents a mini-electronic tongue that used a polymeric sensor array made from polypyrrole to discriminate between coffee samples of different geographical origin. The electronic tongue consisted of a system with a voltammetric sensor array coupled to a multichannel measuring device (multi-potentiostat) that was controlled by a multivariable data collection and processing application. The samples analyzed comprised two types: a series of substances with different chemical and taste properties and a group of samples of coffee of the Arabica variety harvested from different geographical areas of Colombia. The electronic tongue demonstrated the ability to discriminate between solutions with different gustatory properties. In the analysis of the coffee samples, each sensor showed a particular voltammetric response to each of the samples studied. A principal component analysis was undertaken, which resulted in clear discrimination between each of the coffee samples. It was concluded that the portable electronic tongue equipped with polymer sensors is able to discriminate between samples of coffee of different geographical origin.

Historical Evolution and Food Control Achievements of Near Infrared Spectroscopy, Electronic Nose, and Electronic Tongue—Critical Overview

“…Numerous studies have shown the importance of the geographical origin in conferring distinctive quality attributes to the coffee; notwithstanding, traditional techniques of determining this criterion are quite cumbersome. Alternatively, the authors of [ 234 ] attempted to determine the geographical groups of Arabica coffees from Colombia using a mini E-tongue comprising a polymeric sensor array with PPy modified using different counter ions. The acquired results showed the capability of the mini-E-tongue for the geographical based separation of the different coffee samples using PCA.…”

Application of a Polypyrrole Sensor Array Integrated into a Smart Electronic Tongue for the Discrimination of Milk Adulterated with Sucrose

“…This type of device operates on systems comprised of three major components: a sensor array with cross selectivity, an electronic multichannel measurement device, and a data analysis unit utilizing multivariate or pattern recognition techniques (Vlasov et al, 2005). The electronic tongue devices developed were based on different analytical principles, and various sensor arrays have been used (Arrieta et al, 2020;Facure et al, 2020;Zabadaj et al, 2018;Lipkowitz et al, 2018). However, electronic tongues based on electrochemical measurements have received widespread acceptance from the scientific community and the industry, particularly those based on potentiometric and voltammetric sensor arrays (Arrieta et al, 2020;Oroian and Ropciuc, 2019;Lipkowitz et al, 2018).…”

“…The electronic tongue devices developed were based on different analytical principles, and various sensor arrays have been used (Arrieta et al, 2020;Facure et al, 2020;Zabadaj et al, 2018;Lipkowitz et al, 2018). However, electronic tongues based on electrochemical measurements have received widespread acceptance from the scientific community and the industry, particularly those based on potentiometric and voltammetric sensor arrays (Arrieta et al, 2020;Oroian and Ropciuc, 2019;Lipkowitz et al, 2018).…”

“…On the other hand, voltammetric electronic tongues work with electrodes o sensors made of noble metals (platinum, gold, iridium, rhodium, and palladium) or modified electrodes (Arrieta et al, 2020;Wei et al, 2013;Alcañiz et al, 2012). In contrast to potentiometric sensors, they are not limited to detecting charged species and possess desirable properties such as versatility, robustness, and simplicity (Hayat et al, 2019;Khalil et al, 2018).…”

Standardized Extraction Techniques for Meat Analysis with the Electronic Tongue: A Case Study of Poultry and Red Meat Adulteration

“…A detailed head-to-head comparison of some of these instruments and their applications have been reported [ 5 , 9 , 20 , 26 ] but this current study will focus solely on the e- tongue. Ideally, the e-tongue is better suited for liquid samples and combination with chemometric techniques, it has been used to monitor the quality of coffee [ 27 ], wine [ 24 , 28 , 29 ], fruit juice [ 24 ], oils [ 25 , 30 , 31 ], tea [ 32 ], and recently in some semi-solid foods like tomato concentrate [ 33 ]. With mathematical correction methods [ 28 , 29 , 32 , 34 ], signals from the e-tongue sensors can be further optimized to compensate for issues of drift that could arise from environmental factors, such as temperature, relative humidity, etc., or sensor aging [ 5 , 20 , 28 ].…”