Zoltán Kókai

Discrimination of mineral waters by electronic tongue, sensory evaluation and chemical analysis.

Mineral, spring and tap water samples of different geographical origins (7 classes) were distinguished by various methods, such as sensory evaluation, electronic tongue measurement, inductively coupled plasma atomic emission spectroscopy and ion chromatography. Samples from the same geographical origin were correctly classified by chemical analysis and electronic tongue (100%), but it was found that only 80% classification rate can be achieved by sensory evaluation. Different water brands (different brand names) from the same geographical origin did not show definite differences, as expected. Forward stepwise algorithm selected three chemical parameters namely, chloride (Cl(-)), sulphate (SO(4)(2-)) and magnesium (Mg) content and two electronic tongue sensor signals (ZZ and HA) to discriminate according to the geographical origins.

Sweetener Recognition and Taste Prediction of Coke Drinks by Electronic Tongue

Natural and artificial sweetener monitoring methods are getting more important, since soft drinks with low energy play a considerable role in the market. Our objective is to describe the relevant sensory attributes and to determine the applicability of the electronic tongue to discriminate the coke drink samples with different sweeteners. Furthermore, the aim is to find a relationship between the taste attributes and measurement results received by the electronic tongue. An Alpha astree electronic tongue and a trained sensory panel are used to evaluate coke samples. Panelists found significant differences between the samples in 13 cases from the 18 sensory attributes defined previously by the consensus group. The samples are definitely distinguished by the electronic tongue. The main difference is found according to the sweetener content of the samples. The electronic tongue is able to distinguish samples containing different kinds of artificial and natural sweeteners, as well. The electronic tongue is able to predict, by the partial least squares regression method, the taste attributes of the coke drinks determined by the sensory panel with close correlation and low prediction error.

Mineral Water Taste Attributes Evaluated By Sensory Panel And Electronic Tongue

The objective of the current research was to determine relationships between sensory evaluation and measurement results obtained by electronic tongue for mineral waters. Furthermore, the purpose was to predict the sensory characteristics of the mineral waters measured by the electronic tongue and to determine taste differences that cannot be detected by the sensory evaluation. Two mineral waters were definitely different from the others according to the sensory attributes based on profile analysis. With the electronic tongue measurements the PCA and CDA analysis were found to be able to discriminate mineral waters having chemical composition similar to each other. Very good correlation was found between the sensory attributes and the electronic tongue measurements. However, the results of the measurements performed with the electronic tongue showed a more accurate discrimination of the different mineral waters than the sensory evaluation.

Sensory evaluation and electronic tongue for sensing flavored mineral water taste attributes.

In this article a trained sensory panel evaluated 6 flavored mineral water samples. The samples consisted of 3 different brands, each with 2 flavors (pear-lemon grass and josta berry). The applied sensory method was profile analysis. Our aim was to analyze the sensory profiles and to investigate the similarities between the sensitivity of the trained human panel and an electronic tongue device. Another objective was to demonstrate the possibilities for the prediction of sensory attributes from electronic tongue measurements using a multivariate statistical method (Partial Least Squares regression [PLS]). The results showed that the products manufactured under different brand name but with the same aromas had very similar sensory profiles. The panel performance evaluation showed that it is appropriate (discrimination ability, repeatability, and panel consensus) to compare the panels results with the results of the electronic tongue. The samples can be discriminated by the electronic tongue and an accurate classification model can be built. Principal Component Analysis BiPlot diagrams showed that Brand A and B were similar because the manufacturers use the same aroma brands for their products. It can be concluded that Brand C was quite different compared to the other samples independently of the aroma content. Based on the electronic tongue results good prediction models can be obtained with high correlation coefficient (r(2) > 0.81) and low prediction error (RMSEP < 13.71 on the scale of the sensory evaluation from 0 to 100).

Sensory evaluation and electronic tongue analysis for sweetener recognition in coke drinks

Consumption of beverages with low energy has an increasing role. Furthermore hydrolyzed starch products such as inverted syrup show a wide application in the beverage industry. Therefore the importance of methods which can monitor the usage of natural and artificial sweeteners is increasing. The task was to describe the relevant sensory attributes and to determine the applicability of the electronic tongue to discriminate the coke drink samples with different sweeteners. Furthermore the aim was to find relationship between the taste attributes and measurement results provided by electronic tongue. An Alpha Astree Electronic Tongue and a trained sensory panel were used to evaluate the coke samples. Panelists found significant differences between the samples in 15 cases from the 18 sensory attributes defined previously by the consensus group. Coke drinks containing different kind of sweeteners can be characterized according to these sensory attributes. The samples were definitely distinguished by the electr...