Caffeic acid is one of the most important hydroxycinnamic acids found in various foods and plant products. It has multiple beneficial effects in the human body such as antioxidant, antibacterial, anti-inflammatory, and antineoplastic.... more
Caffeic acid is one of the most important hydroxycinnamic acids found in various foods and plant products. It has multiple beneficial effects in the human body such as antioxidant, antibacterial, anti-inflammatory, and antineoplastic. Since overdoses of caffeic acid may have negative effects, the quality and quantity of this acid in foods, pharmaceuticals, food supplements, etc., needs to be accurately determined. The present paper analyzes the most representative scientific papers published mostly in the last 10 years which describe the development and characterization of voltamperometric sensors or biosensors based on carbon nanomaterials and/or enzyme commonly used for detecting caffeic acid and a series of methods which may improve the performance characteristics of such sensors.
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The analysis of antioxidants in different foodstuffs has become an active area of research, which has led to many recently developed antioxidant assays. Many antioxidants exhibit inherent electroactivity, and, therefore, the use of... more
The analysis of antioxidants in different foodstuffs has become an active area of research, which has led to many recently developed antioxidant assays. Many antioxidants exhibit inherent electroactivity, and, therefore, the use of electrochemical methods could be a viable approach for evaluating the overall antioxidant activity of a matrix of nutraceuticals without the need for adding reactive species. Green tea is believed to be a healthy beverage due to a number of therapeutic benefits. Catechin, one of its constituents, is an important antioxidant and possesses free radical scavenging abilities. The present paper describes the electrochemical properties of three screen-printed electrodes (SPEs), the first one based on carbon nanotubes (CNTs), the second one based on gold nanoparticles (GNPs) and the third one based on carbon nanotubes and gold nanoparticles (CNTs-GNPs). All three electrodes were modified with the laccase (Lac) enzyme, using glutaraldehyde as a cross-linking agen...
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The present study describes the electrochemical properties of three screen-printed electrodes (SPEs), the first electrode being carbon-based (C), the second graphene-based (GPH), and the third based on GPH modified with gold nanoparticles... more
The present study describes the electrochemical properties of three screen-printed electrodes (SPEs), the first electrode being carbon-based (C), the second graphene-based (GPH), and the third based on GPH modified with gold nanoparticles (GNP). These electrodes were used for the study of the electrochemical behavior of chlorogenic acid in different aqueous solutions, at pH = 7. In chlorogenic acid solution, a redox process was noticed in the case of all three electrodes; GPH and GNP significantly improved the sensor response regarding sensitivity and reversibility, a fact demonstrated by characterizing the sensor by cyclic voltammetry in potassium ferrocyanide, which corresponds to the exchange of two electrons and two protons. Moreover, the calibration curves for each sensor were developed, subsequently calculating the detection limits (LOD) and the quantification limits (LOQ). Low LOD and LOQ were obtained, the best—of the order of 10−7 M (LOD = 0.62 × 10−7 M; LOQ = 1.97 × 10−7 M...
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Quality and safety have become important food attributes within the last years. With the expansion of food industry and food fabrication on a big scale is not infrequent to found adulterant and contaminant on food, i.e. of harmful... more
Quality and safety have become important food attributes within the last years. With the expansion of food industry and food fabrication on a big scale is not infrequent to found adulterant and contaminant on food, i.e. of harmful chemicals and microorganisms, which can cause consumer illness. Increasingly, the public authorities are charging the food industry to develop quality management systems and restructure the food inspection system to improve food quality and safety. However, contamination can be taking place during all steps of food manufacturing. For instance, even during storage, the products can experience a significant degradation in quality due to a variety of physical, chemical, and biological interactions. Consequently, fast and inexpensive ways to control the food freshness, contamination or adulteration are requested to keep the quality control. Thus, there is an increasing demand for analytical methods easily operate with highly sensitive, selective and accurate f...
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In industry and food supply chain there is an increasing need for integrated monitoring system to assure product quality. In particular, in the fishing industry, the detection of amines with an integrated system can allow real time and... more
In industry and food supply chain there is an increasing need for integrated monitoring system to assure product quality. In particular, in the fishing industry, the detection of amines with an integrated system can allow real time and on-field analyses of products during the whole production and delivering process. This work presents the development of silicon microcantilever-based sensor arrays designed for integration in a chromatographic system for food quality monitoring applications. Microcantilevers are MEMS-structures suitable for chemical sensing; sensitivity to specific analytes can be achieved by coating the beam surface with proper chemically sensitive films. Analyte adsorption onto the surface affects both resonance frequency and beam bending, leading to different read-out approach which can be also combined. In this work, four-beam arrays have been designed and realised with a CMOS-compatible process in order to monitor the shift of the resonant frequency due to mass a...
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Electrochemical sensors, sensor arrays and biosensors, alongside chemometric instruments, have progressed remarkably of late, being used on a wide scale in the qualitative and quantitative evaluation of olive oil. Olive oil is a natural... more
Electrochemical sensors, sensor arrays and biosensors, alongside chemometric instruments, have progressed remarkably of late, being used on a wide scale in the qualitative and quantitative evaluation of olive oil. Olive oil is a natural product of significant importance, since it is a rich source of bioactive compounds with nutritional and therapeutic properties, and its quality is important both for consumers and for distributors. This review aims at analysing the progress reported in the literature regarding the use of devices based on electrochemical (bio)sensors to evaluate the bioactive compounds in olive oil. The main advantages and limitations of these approaches on construction technique, analysed compounds, calculus models, as well as results obtained, are discussed in view of estimation of future progress related to achieving a portable, practical and rapid miniature device for analysing the quality of virgin olive oil (VOO) at different stages in the manufacturing process.
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This study describes the development of a new sensor with applicability in the determination and quantification of yjr essential amino acid (AA) L-tryptophan (L-TRP) from pharmaceutical products. The proposed sensor is based on a carbon... more
This study describes the development of a new sensor with applicability in the determination and quantification of yjr essential amino acid (AA) L-tryptophan (L-TRP) from pharmaceutical products. The proposed sensor is based on a carbon screen-printed electrode (SPCE) modified with the conductor polymer polypyrrole (PPy) doped with potassium hexacyanoferrate (II) (FeCN). For the modification of the SPCE with the PPy doped with FeCN, the chronoamperometry (CA) method was used. For the study of the electrochemical behavior and the sensitive properties of the sensor when detecting L-TRP, the cyclic voltammetry (CV) method was used. This developed electrode has shown a high sensibility, a low detection limit (LOD) of up to 1.05 × 10−7 M, a quantification limit (LOQ) equal to 3.51 × 10−7 M and a wide linearity range between 3.3 × 10−7 M and 1.06 × 10−5 M. The analytical performances of the device were studied for the detection of AA L-TRP from pharmaceutical products, obtaining excellent...
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Virgin olive oils contain natural compounds of high added value and specific organoleptic properties. Using reliable, precise, and accurate equipment is essential in the detection of inadequate characteristics of virgin olive oil.... more
Virgin olive oils contain natural compounds of high added value and specific organoleptic properties. Using reliable, precise, and accurate equipment is essential in the detection of inadequate characteristics of virgin olive oil. However, the use of traditional analytical techniques is limited by the need for expensive instrumentation and complex sample preparation. One of the most promising ways of developing rapid, sensitive, and inexpensive methods for quality control in virgin olive oils is the use of multisensor systems. However, using the electronic nose or the electronic tongue individually can provide incomplete information about virgin olive oils. Therefore, the use of fusion technology to study olive oil properties can provide a complete characterization of olive oils. The most important contributions dealing with the electronic sensory characterization of virgin olive oils using the fusion technology between electronic noses and electronic tongues are described in this chapter.
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Consumers are increasingly interested in the characteristics of the products they consume, including aroma, taste, and appearance, and hence, scientific research was conducted in order to develop electronic senses devices that mimic the... more
Consumers are increasingly interested in the characteristics of the products they consume, including aroma, taste, and appearance, and hence, scientific research was conducted in order to develop electronic senses devices that mimic the human senses. Thanks to the utilization of electroanalytical techniques that used various sensors modified with different electroactive materials coupled with pattern recognition methods, artificial senses such as electronic tongues (ETs) are widely applied in food analysis for quality and authenticity approaches. This paper summarizes the applications of electrochemical sensors (voltammetric, amperometric, and potentiometric) coupled with unsupervised and supervised pattern recognition methods (principal components analysis (PCA), linear discriminant analysis (LDA), partial least square (PLS) regression, artificial neural network (ANN)) for wine authenticity assessments including the discrimination of varietal and geographical origins, monitoring th...
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Angiogenesis is a physiological process involving the growth of new blood vessels, which provides oxygen and required nutrients for the development of various pathological conditions. In a tumor microenvironment, this process upregulates... more
Angiogenesis is a physiological process involving the growth of new blood vessels, which provides oxygen and required nutrients for the development of various pathological conditions. In a tumor microenvironment, this process upregulates the growth and proliferation of tumor cells, thus any stage of angiogenesis can be a potential target for cancer therapies. In the present study, chitosan and his derivatives have been used to design novel polymer-based nanoparticles. The therapeutic potential of these newly designed nanoparticles has been evaluated. The antioxidant and MTT assays were performed to know the antioxidant properties and their biocompatibility. The in vivo antiangiogenic properties of the nanoparticles were evaluated by using a chick Chorioallantoic Membrane (CAM) model. The obtained results demonstrate that chitosan derivatives-based nanostructures strongly enhance the therapeutic effect compared to chitosan alone, which also correlates with antitumor activity, demonst...
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In recent years, researchers have focused on developing simple and efficient methods based on electrochemical biosensors to determine hydroxycinnamic acids from various real samples (wine, beer, propolis, tea, and coffee). Enzymatic... more
In recent years, researchers have focused on developing simple and efficient methods based on electrochemical biosensors to determine hydroxycinnamic acids from various real samples (wine, beer, propolis, tea, and coffee). Enzymatic biosensors represent a promising, low-cost technology for the direct monitoring of these biologically important compounds, which implies a fast response and simple sample processing procedures. The present review aims at highlighting the structural features of this class of compounds and the importance of hydroxycinnamic acids for the human body, as well as presenting a series of enzymatic biosensors commonly used to quantify these phenolic compounds. Enzyme immobilization techniques on support electrodes are very important for their stability and for obtaining adequate results. The following sections of this review will briefly describe some of the laccase (Lac) and tyrosinase (Tyr) biosensors used for determining the main hydroxycinnamic acids of inter...
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The present review deals with the recent progress made in the field of the electrochemical detection of serotonin by means of electrochemical sensors based on various nanomaterials incorporated in the sensitive element. Due to the unique... more
The present review deals with the recent progress made in the field of the electrochemical detection of serotonin by means of electrochemical sensors based on various nanomaterials incorporated in the sensitive element. Due to the unique chemical and physical properties of these nanomaterials, it was possible to develop sensitive electrochemical sensors with excellent analytical performances, useful in the practice. The main electrochemical sensors used in serotonin detection are based on carbon electrodes modified with carbon nanotubes and various materials, such as benzofuran, polyalizarin red-S, poly(L-arginine), Nafion/Ni(OH)2, or graphene oxide, incorporating silver-silver selenite nanoparticles, as well as screen-printed electrodes modified with zinc oxide or aluminium oxide. Also, the review describes the nanocomposite sensors based on conductive polymers, tin oxide-tin sulphide, silver/polypyrole/copper oxide or a hybrid structure of cerium oxide-gold oxide nanofibers togeth...
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This paper describes the sensitive properties of screen-printed carbon electrodes (SPCE) modified by using three different electroactive chemical compounds: Meldola’s Blue, Cobalt Phthalocyanine and Prussian Blue, respectively. It was... more
This paper describes the sensitive properties of screen-printed carbon electrodes (SPCE) modified by using three different electroactive chemical compounds: Meldola’s Blue, Cobalt Phthalocyanine and Prussian Blue, respectively. It was demonstrated that the Prussian Blue (PB) modified SPCE presented electrochemical signals with the highest performances in terms of electrochemical process kinetics and sensitivity in all the solutions analyzed. PB-SPCE was demonstrated to detect Phe through the influence it exerts on the redox processes of PB. The PB-SPCE calibration have shown a linearity range of 0.33–14.5 µM, a detection limit (LOD) of 1.23 × 10−8 M and the standard deviation relative to 3%. The PB-SPCE sensor was used to determine Phe by means of calibration and standard addition techniques on pure samples, on simple pharmaceutical samples or on multicomponent pharmaceutical samples. Direct determination of the concentration of 4 × 10−6–5 × 10−5 M Phe in KCl solution showed that th...
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Levodopa is a precursor of dopamine, having important beneficial effects in the treatment of Parkinson’s disease. In this study, levodopa was accurately detected by means of cyclic voltammetry using carbon-based (C-SPCE), mesoporous... more
Levodopa is a precursor of dopamine, having important beneficial effects in the treatment of Parkinson’s disease. In this study, levodopa was accurately detected by means of cyclic voltammetry using carbon-based (C-SPCE), mesoporous carbon (MC-SPCE) and ordered mesoporous carbon (OMC-SPCE)-modified screen-printed sensors. Screen-printed carbon sensors were initially used for the electrochemical detection of levodopa in a 10−3 M solution at pH 7.0. The mesoporous carbon with an organized structure led to better electroanalysis results and to lower detection and quantification limits of the OMC-SPCE sensor as compared to the other two studied sensors. The range of linearity obtained and the low values of the detection (0.290 µM) and quantification (0.966 µM) limit demonstrate the high sensitivity and accuracy of the method for the determination of levodopa in real samples. Therefore, levodopa was detected by means of OMC-SPCE in three dietary supplements produced by different manufact...
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Caffeic acid may be accurately detected in food supplements by using cyclic voltammetry and carbon screen-printed sensors modified with various nanomaterials. Sensor characterization by cyclic voltammetry in reference solutions has shown... more
Caffeic acid may be accurately detected in food supplements by using cyclic voltammetry and carbon screen-printed sensors modified with various nanomaterials. Sensor characterization by cyclic voltammetry in reference solutions has shown that carbon nanotubes or carbon nanofibers significantly improve the sensor response in terms of sensitivity and reversibility. Screen-printed sensors were then used in order to study the electrochemical behavior of caffeic acid in aqueous solution at pH 3.6. A redox process was observed in all cases, which corresponds to a reversible redox process involving the transfer of two electrons and two protons. The role of nanomaterials in the increment of sensor performance characteristics was evidenced. Calibration curves were developed for each sensor, and the detection (LOD) and quantification (LOQ) limits were calculated. Low LOD and LOQ values were obtained, in the 10−7 to 10−9 M range, which demonstrates that the method is feasible for quantificatio...
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The study of antioxidants and their implications in various fields, from food engineering to medicine and pharmacy, is of major interest to the scientific community. The present paper is a critical presentation of the most important tests... more
The study of antioxidants and their implications in various fields, from food engineering to medicine and pharmacy, is of major interest to the scientific community. The present paper is a critical presentation of the most important tests used to determine the antioxidant activity, detection mechanism, applicability, advantages and disadvantages of these methods. Out of the tests based on the transfer of a hydrogen atom, the following were presented: the Oxygen Radical Absorption Capacity (ORAC) test, the Hydroxyl Radical Antioxidant Capacity (HORAC) test, the Total Peroxyl Radical Trapping Antioxidant Parameter (TRAP) test, and the Total Oxyradical Scavenging Capacity (TOSC) test. The tests based on the transfer of one electron include the Cupric Reducing Antioxidant Power (CUPRAC) test, the Ferric Reducing Antioxidant Power (FRAP) test, the Folin–Ciocalteu test. Mixed tests, including the transfer of both a hydrogen atom and an electron, include the 2,2′-Azinobis-(3-ethylbenzothia...
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The present paper deals with the electrochemical behavior of three types of sensors based on modified screen-printed electrodes (SPEs): a sensor based on carbon nanofibers (CNF/SPE), a sensor based on nanofibers of carbon modified with... more
The present paper deals with the electrochemical behavior of three types of sensors based on modified screen-printed electrodes (SPEs): a sensor based on carbon nanofibers (CNF/SPE), a sensor based on nanofibers of carbon modified with gold nanoparticles (CNF-GNP/SPE) and a biosensor based on nanofibers of carbon modified with gold nanoparticles and tyrosinase (CNF-GNP-Ty/SPE). To prepare the biosensor, the tyrosinase (Ty) was immobilized on the surface of the electrode already modified with carbon nanofibers and gold nanoparticles, by the drop-and-dry technique. The electrochemical properties of the three electrodes were studied by cyclic voltammetry in electroactive solutions, and the position and shape of the active redox peaks are according to the nature of the materials modifying the electrodes. In the case of ferulic acid, a series of characteristic peaks were observed, the processes being more intense for the biosensor, with the higher sensitivity and selectivity being due to...
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ABSTRACT
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Phenolic compounds are a very complex group of natural compounds that contribute directly to the flavor, namely to the bitterness and astringency perceived in a variety of food and beverages such as unripe fruits, wines, teas and beers.... more
Phenolic compounds are a very complex group of natural compounds that contribute directly to the flavor, namely to the bitterness and astringency perceived in a variety of food and beverages such as unripe fruits, wines, teas and beers. The phenolic compounds are major components in wines, which are generally recognized as an essential component of wine quality. They provide color, astringency and bitterness to wine. The phenolic composition of the wines depends on the grape and winemaking practices. Polyphenols are implied in different reactions starting as soon as the grape is crushed, continuing throughout winemaking and aging process. These reactions influence the aroma release and the perception sensory properties, thus modifying the quality of the wines. The production of the wine is completely dependent on the long-lasting experience of wine makers and quality of input products. For these reasons, it is necessary to monitor the quality of wine. The adequate control involves c...
ABSTRACT In industry and food supply chain there is an increasing need for integrated monitoring system to assure product quality. In particular, in the fishing industry, the detection of amines with an integrated system can allow real... more
ABSTRACT In industry and food supply chain there is an increasing need for integrated monitoring system to assure product quality. In particular, in the fishing industry, the detection of amines with an integrated system can allow real time and on-field analyses of products during the whole production and delivering process. This work presents the development of silicon microcantilever-based sensor arrays designed for integration in a chromatographic system for food quality monitoring applications. Microcantilevers are MEMS-structures suitable for chemical sensing; sensitivity to specific analytes can be achieved by coating the beam surface with proper chemically sensitive films. Analyte adsorption onto the surface affects both resonance frequency and beam bending, leading to different read-out approach which can be also combined. In this work, four-beam arrays have been designed and realised with a CMOS-compatible process in order to monitor the shift of the resonant frequency due to mass adsorption on the beam surface. The realised devices have been designed to work up to the third resonance mode in order to take advantage of the higher working frequencies, and in the frequency range from 10 to 180kHz. An integrated piezoresistive Wheatstone bridge read-out has been used in order to enhance sensitivity and to reduce read-out temperature dependence. The selected sensitive materials were Lutetium and Cobalt-Phtalocyanines. The read-out electronic that has been developed is based on a feedback system for measuring the frequency shift of the beam, allowing an increase of the resonance quality factor and frequency resolution of more than one order of magnitude. The selected configuration uses a PLL in locked state to follow the frequency of the cantilever and give the signal to the piezo-driver in order to maintain the system at resonance.
ABSTRACT This work reports tyrosinase based electrochemical biosensors using graphene modified screen-printed carbon based electrodes for the determination of catecholamines. The enzyme has been immobilized onto the graphene modified... more
ABSTRACT This work reports tyrosinase based electrochemical biosensors using graphene modified screen-printed carbon based electrodes for the determination of catecholamines. The enzyme has been immobilized onto the graphene modified carbon working electrodes by cross-linking with glutaraldehyde. The detection has been performed by measuring the cathodic current due to the reduction of the corresponding quinone a low potential, 0.025 V for dopamine and -0.025 V for epinephrine, respectively. The experimental conditions for the tyrosinase immobilization and the main variables that can influence the cathodic current have been optimized. Under optimum conditions, the electrochemical biosensors have been characterized. A linear response range from 0.2 up to 25 M of dopamine and from 1 to 27.5 M of epinephrine was obtained. The detection limits are in the range 2.42×10-7 - 6.56×10-7 M for developed biosensors. The biosensors construction was highly reproducible. Finally, the developed biosensors have been applied to the determination of dopamine and epinephrine content in pharmaceutical formulation samples.
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A combination of an electronic nose, an electronic tongue and an electronic eye has been used to discriminate between red wines aged in oak barrels and red wines matured in steel tanks in contact with oak wood chips. The quality of wines... more
A combination of an electronic nose, an electronic tongue and an electronic eye has been used to discriminate between red wines aged in oak barrels and red wines matured in steel tanks in contact with oak wood chips. The quality of wines has also been analyzed by means of conventional chemical methods. Principal component analysis has demonstrated that both methods
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Research Interests: Food Engineering, Carbon Nanotubes, Histamine, FISH, HPLC, and 9 moreBiosensor, LOD, PBS, Food Sciences, RSD, Tyrosinase, H, SPE, and Catechol
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The development of phenol oxydase biosensors is of great interest due to the importance of phenols and polyphenols in the food industry. To retain the enzyme specific biological function, the appropriate immobilisation of the enzyme on a... more
The development of phenol oxydase biosensors is of great interest due to the importance of phenols and polyphenols in the food industry. To retain the enzyme specific biological function, the appropriate immobilisation of the enzyme on a solid matrix is a key factor. Tyrosinase and Lacasse biosensors have been developed using a variety of techniques that include covalent immobilization, screen
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ABSTRACT The detection of adulteration in extra virgin olive oils is of great interest in food industry. This article presents the first use of a voltammetric e-tongue for the detection of the adulteration of virgin olive oil.... more
ABSTRACT The detection of adulteration in extra virgin olive oils is of great interest in food industry. This article presents the first use of a voltammetric e-tongue for the detection of the adulteration of virgin olive oil. Adulterations of an extra virgin olive oil with different percentages of sunflower oil, soybean oil and corn oil were measured using modified carbon paste based sensors. The square wave voltammetric signals were processed using kernel method. Chemometric methods applied allows discrimination and classification of oils in agreement with botanical origins. Excellent correlations between voltammetric signals and polyphenolic content was obtained by PLS regression. PLS-DA and PLS regression demonstrated the feasibility of detecting adulterations of olive oil with percentages lower than 10% of sunflower, soybean and corn oils. These results indicate that e-tongue can be a useful tool for the detection of olive oil adulteration with seed oils.
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ABSTRACT An electrochemical tyrosinase electrode for detection of tyramine was developed via cross-linking immobilization method over phosphate-doped polypyrrole film. The enzyme tyrosinase immobilized over the polypyrrole thin film... more
ABSTRACT An electrochemical tyrosinase electrode for detection of tyramine was developed via cross-linking immobilization method over phosphate-doped polypyrrole film. The enzyme tyrosinase immobilized over the polypyrrole thin film preserves well its biocatalytic activity. Tyramine was determined by the direct reduction of biocatalytically formed dopaquinone at −0.250 V. The analytical characteristics of this biosensor, including linear range, detection limit, repeatability and storage stability are described. The kinetics of the enzymatic reaction fitted into a Michaelis–Menten type kinetic, as confirmed by the h parameter close to 1 obtained from the Hill's plot. Under the optimum conditions, the current response had a linear relationship with the concentration of tyramine in the range of 4–80 × 10−6 M, with a sensitivity of 0.1069 A M−1 and a limit of detection of 5.7 × 10−7 M. The biosensor exhibited high repeatability and long term stability. Determination of tyramine in real samples showed good recovery. The selective detection is related to specific action of tyrosinase toward phenolic group from tyramine (1-hydroxy-4-ethylaminobenzene). The developed biosensor was applied to the determination of the tyramine content in sauerkraut samples.