Antioxidant activity and physico-chemical parameters for the differentiation of honey using a potentiometric electronic tongue.

BACKGROUND: This work evaluates the capacity of a potentiometric electronic tongue to differentiate between types of honey (orange blossom, rosemary, thyme, sunflower, winter savory and honeydew honey) according to their antioxidant level. The classical procedures used to evaluate the antioxidant potential of honey are inappropriate for in situ monitoring on reception of batches of raw honey in the packaging industry. They are also destructive, time-consuming and very tedious, requiring highly expert analysts and specialised equipment. RESULTS: The electronic tongue system made with Ag, Ni, Co, Cu and Au was able to not only differentiate between types of honey but also to predict their total antioxidant capacity. The discrimination ability of the system was proved by means of a fuzzy ARTMAP type ANN, with 100% classification success. A prediction multiple linear regression model showed that the best correlation coefficient was for antioxidant activity (0.9666), then for electrical conductivity (0.8959) and to a lesser extent for aw , moisture and colour. CONCLUSION: The proposed measurement system could be a quick, easy option for the honey packaging sector to provide continuous in-line information about a characteristic as important as the antioxidant level. © 2016 Society of Chemical Industry.

Development of potentiometric equipment for the identification of altered dry-cured hams: A preliminary study.

Microbiological contamination in dry-cured ham can occur in the early stages of the process, a large number of microorganisms involved in spoilage can produce alterations in the product. These include non-common odours, which are detected at the end of the process by a procedure called "cala", consisting of a sharp instrument punctured in every ham; this is smelled by an expert taster, who classifies hams as good and altered hams. An electronic device would be suitable for this process given the large amount of hams. The present research aims to develop objective equipment based on the potentiometry technique that identifies altered hams. A probe was developed, containing silver, nickel and copper electrodes, and was employed to classify altered and unaltered hams prior to classification by a tester. The results shown lower Ag and higher Cu potential values for altered hams. The differences in potentiometric response reveal a classification model, although further studies are required to obtain a reliable classification model.

An electronic tongue designed to detect ammonium nitrate in aqueous solutions.

An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni) encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH4)2SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate.