A taste sensor device for unmasking admixing of rancid or winey-vinegary olive oil to extra virgin olive oil

Electrochemical sensor devices have gathered great attention in food analysis namely for olive oil evaluation. The adulteration of extra-virgin olive oil with lower-grade olive oil is a common worldwide fraudulent practice, which detection is a challenging task. The potentiometric fingerprints recorded by lipid polymeric sensor membranes of an electronic tongue, together with linear discriminant analysis and simulated annealing meta-heuristic algorithm, enabled the detection of extra-virgin olive oil adulterated with olive oil for which an intense sensory defect could be perceived, specifically rancid or winey-vinegary negative sensations. The homemade designed taste device allowed the identification of admixing of extra-virgin olive oil with more than 2.5% or 5% of rancid or winey-vinegary olive oil, respectively. Predictive mean sensitivities of 84±4% or 92±4% and specificities of 79±6% or 93±3% were obtained for rancid or winey-vinegary adulterations, respectively, regarding an internal-validation procedure based on a repeated K-fold cross-validation variant (4 folds×10 repeats, ensuring that the dataset was forty times randomly split into 4 folds, leaving 25% of the data for validation purposes). This performance was satisfactory since, according to the legal physicochemical and sensory analysis, the intentionally adulterated olive oil with percentages of 2.510%, could still be commercialized as virgin olive oil. It could also be concluded that at a 5% significance level, the trained panelists could not distinguish extra-virgin olive oil samples from those adulterated with 2.5% of rancid olive oil or up to 5% of winey-vinegary olive oil. Thus, the electronic tongue proposed in this study can be foreseen as a practical and powerful tool to detect this kind of worldwide common fraudulent practice of high quality olive oil.This work was financially supported by Project POCI-01–0145FEDER-006984 – Associate Laboratory LSRE-LCM, Project UID/QUI/ 00616/2013 – CQ-VR, Project UID/BIO/04469/2013 – CEB and strategic project PEst-OE/AGR/UI0690/2014 – CIMO all funded by FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT - Fundação para a Ciência e a Tecnologia, Portugal. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014). Souheib Oueslati is also grateful for the support of the Tunisian Ministry of Agriculture.info:eu-repo/semantics/publishedVersio

Electronic noses and tongues to assess food authenticity and adulteration

[EN] Background: There is a growing concern for the problem of food authenticity assessment (and hence the detection of food adulteration), since it cheats the consumer and can pose serious risk to health in some instances. Unfortunately, food safety/integrity incidents occur with worrying regularity, and therefore there is clearly a need for the development of new analytical techniques. Scope and approach: In this review, after briefly commenting the principles behind the design of electronic noses and electronic tongues, the most relevant contributions of these sensor systems in food adulteration control and authenticity assessment over the past ten years are discussed. It is also remarked that future developments in the utilization of advanced sensors arrays will lead to superior electronic senses with more capabilities, thus making the authenticity and falsification assessment of food products a faster and more reliable process. Key findings and conclusions: The use of both types of e-devices in this field has been steadily increasing along the present century, mainly due to the fact that their efficiency has been significantly improved as important developments are taking place in the area of data handling and multivariate data analysis methods. (C) 2016 Elsevier Ltd. All rights reserved.Peris Tortajada, M.; Escuder Gilabert, L. (2016). Electronic noses and tongues to assess food authenticity and adulteration. Trends in Food Science and Technology. 58:40-54. doi:10.106/j.tifs.2016.10.014S40545

Electrochemical sensor-based devices for assessing bioactive compounds in olive oils: a brief review

Electrochemical bioinspired sensor devices combined with chemometric tools have experienced great advances in the last years, being extensively used for food qualitative and quantitative evaluation, namely for olive oil analysis. Olive oil plays a key role in the Mediterranean diet, possessing unique and recognized nutritional and health properties as well as highly appreciated organoleptic characteristics. These positive attributes are mainly due to olive oil richness in bioactive compounds such as phenolic compounds. In addition, these compounds enhance their overall sensory quality, being mainly responsible for the usual olive oil pungency and bitterness. This review aims to compile and discuss the main research advances reported in the literature regarding the use of electrochemical sensor based-devices for assessing bioactive compounds in olive oil. The main advantages and limitations of these fast, accurate, bioinspired voltammetric, potentiometric and/or amperometric sensor green-approaches will be addressed, aiming to establish the future challenges for becoming a practical quality analytical tool for industrial and commercial applications.This research was funded by Project POCI-01–0145-FEDER-006984–Associate Laboratory LSRE-LCM, Project UID/BIO/04469/2013–CEB, Project UID/QUI/50006/2013–REQUIMTE-LAQV and strategic project PEst-OE/AGR/UI0690/2014–CIMO all funded by European Regional Development Fund (ERDF) through COMPETE2020–Programa Operacional Competitividade e Internacionalização (POCI)–and by national funds through FCT–Fundação para a Ciência e a Tecnologia I.P. Ítala G. Marx also acknowledges the research grant provided by Project UID/EQU/50020/2013 and POCI-01-0145-FEDER-006984. The APC was kindly waived by MDPI.info:eu-repo/semantics/publishedVersio

Perception of olive oils sensory defects using a potentiometric taste device

The capability of perceiving olive oils sensory defects and intensities plays a key role on olive oils quality grade classification since olive oils can only be classified as extra-virgin if no defect can be perceived by a human trained sensory panel. Otherwise, olive oils may be classified as virgin or lampante depending on the median intensity of the defect predominantly perceived and on the physicochemical levels. However, sensory analysis is time-consuming and requires an official sensory panel, which can only evaluate a low number of samples per day. In this work, the potential use of an electronic tongue as a taste sensor device to identify the defect predominantly perceived in olive oils was evaluated. The potentiometric profiles recorded showed that intra- and inter-day signal drifts could be neglected (i.e., relative standard deviations lower than 25%), being not statistically significant the effect of the analysis day on the overall recorded E-tongue sensor fingerprints (P-value=0.5715, for multivariate analysis of variance using Pillai's trace test), which significantly differ according to the olive oils sensory defect (P-value=0.0084, for multivariate analysis of variance using Pillai's trace test). Thus, a linear discriminant model based on 19 potentiometric signal sensors, selected by the simulated annealing algorithm, could be established to correctly predict the olive oil main sensory defect (fusty, rancid, wet-wood or winey-vinegary) with average sensitivity of 75±3% and specificity of 73±4% (repeated K-fold cross-validation variant: 4 folds×10 repeats). Similarly, a linear discriminant model, based on 24 selected sensors, correctly classified 92±3% of the olive oils as virgin or lampante, being an average specificity of 93±3% achieved. The overall satisfactory predictive performances strengthen the feasibility of the developed taste sensor device as a complementary methodology for olive oils defects analysis and subsequent quality grade classification. Furthermore, the capability of identifying the type of sensory defect of an olive oil may allow establishing helpful insights regarding bad practices of olives or olive oils production, harvesting, transport and storage.This work was financially supported by Project POCI-01–0145FEDER-006984 – Associate Laboratory LSRE-LCM, Project UID/QUI/ 00616/2013 – CQ-VR, and UID/AGR/00690/2013 – CIMO all funded by FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT Fundação para a Ciência e a Tecnologia, Portugal. Strategic funding of UID/BIO/04469/2013 unit is also acknowledged. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/ 104038/2014).info:eu-repo/semantics/publishedVersio

Assessment of table olives' organoleptic defect intensities based on the potentiometric fingerprint recorded by an electronic tongue

Table olives are prone to the appearance of sensory defects that decrease their quality and in some cases result in olives unsuitable for consumption. The evaluation of the type and intensity of the sensory negative attributes of table olives is recommended by the International Olive Council, although not being legally required for commercialization. However, the accomplishment of this task requires the training and implementation of sensory panels according to strict directives, turning out in a time-consuming and expensive procedure that involves a degree of subjectivity. In this work, an electronic tongue is proposed as a taste sensor device for evaluating the intensity of sensory defects of table olives. The potentiometric signal profiles gathered allowed establishing multiple linear regression models, based on the most informative subsets of signals (from 24 to 29 recorded during the analysis of olive aqueous pastes and brine solutions) selected using a simulated annealing meta-heuristic algorithm. The models enabled the prediction of the median intensities (R2 ≥ 0.942 and RMSE ≤ 0.356, for leave-one-out or repeated K-fold cross-validation procedures) of butyric, musty, putrid, winey-vinegary, and zapateria negative sensations being, in general, the predicted intensities within the range of intensities perceived by the sensory panel. Indeed, based on the predicted mean intensities of the sensory defects, the electrochemical-chemometric approach developed could correctly classify 86.4% of the table olive samples according to their trade category based on a sensory panel evaluation and following the International Olive Council regulations (i.e., extra, 1st choice, 2nd choice, and olives that may not be sold as table olives). So, the satisfactory overall predictions achieved demonstrate that the electronic tongue could be a complementary tool for assessing table olive defects, reducing the effort of trained panelists and minimizing the risk of subjective evaluations.This work was financially supported by Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRE-LCM, by Project UID/QUI/00616/2013 —CQ-VR, and UID/AGR/00690/ 2013—CIMO, all funded by Fundo Europeu de Desenvolvimento Regional (FEDER) through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through Fundação para a Ciência e a Tecnologia (FCT), Portugal. Strategic funding of UID/BIO/04469/2013 unit is also acknowledged. Nuno Rodrigues thanks FCT, POPH-QREN, and FSE for the Ph.D. Grant (SFRH/BD/104038/2014).info:eu-repo/semantics/publishedVersio

Food Authentication: Techniques, Trends and Emerging Approaches

Multiple factors can directly influence the chemical composition of foods and, consequently, their organoleptic, nutritional, and bioactive properties, including their geographical origin, the variety or breed, as well as the conditions of cultivation, breeding, and/or feeding, among others. Therefore, there is a great interest in the development of accurate, robust, and high-throughput analytical methods to guarantee the authenticity and traceability of foods. For these purposes, a large number of sensorial, physical, and chemical approaches can be used, which must be normally combined with advanced statistical tools. In this vein, the aim of the Special Issue “Food Authentication: Techniques, Trends, and Emerging Approaches” is to gather original research papers and review articles focused on the development and application of analytical techniques and emerging approaches in food authentication. This Special Issue comprises 12 valuable scientific contributions, including one review article and 11 original research works, dealing with the authentication of foods with great commercial value, such as olive oil, Iberian ham, and fruits, among others

Estudio teórico y aplicado del potencial de la espectrometría de movilidad iónica

Ion mobility spectrometry (IMS) is an analytical technique based on the separation of gaseous ions under the influence of an electric field through an inert gas atmosphere. Some of the main limitations of IMS, depending on the context, may be the limited quantification capacity of compounds in real samples since narrow linear quantification ranges are normally obtained; the low selectivity due to the low resolution power of this type of equipment; and the difficulty of unequivocally identifying compounds in real samples since the existing databases are not as up-to-date as for other technologies such as mass spectrometry (MS). Therefore, it is evident that there is a demand for more selective methodologies and that provide greater analyte detection and quantification capacity. With these premises, it can be said that the greatest current challenge of the IMS is to maximize the detection capacity of the technique in order to achieve the unambiguous identification of a high number of analytes. This challenge is currently utopian when working with complex samples. For this reason, the main motivation of this Doctoral Thesis was to seek solutions for the different challenges that the IMS currently faces in a theoretical and applied context. The basic objective of the research was to explore the potential of IMS by using theoretical and applied strategies to improve the detection and identification coverage of the analysis carried out with this technology. These new strategies were applied throughout the main steps of the analytical process and allowed improving basic analytical features such as the selectivity and sensitivity of optimized analysis methods and their detection capacity. The achievement of this basic objective leaded to analysis methods of standards and real samples, such as explosives, drugs, soil, rosemary plant, olives and mainly different types of olive oils. This basic objective was divided into three general objectives according to the different research topics to address in this Doctoral Thesis: a) To take benefits derived from the study of theoretical aspects of IMS for improving the interpretation of IMS spectra and from the use of additional features such as structural information to enhance qualitative analysis; b) To develop approaches to improve the detection and identification capacity in IMS analysis; and c) To exploit the opportunities of gas chromatography (GC)-IMS and IMS devices for food analysis as an expanding application area in IMS based on untargeted analysis methods. In this context, the Thesis has included the following studies: (i) To study about the fundamentals of the formation of product ions through the modeling of ions stability using ab initio computations to math these results with the spectral patterns and structure of ions [1]. (ii) To explore the fragmentation of ions using an external electric field and the potential of the extra information of these fragments to enhance the rates of categorization by chemical class using neural networks [2]. (iii) To explore a thermal desorption (TD)-IMS device to obtain spectral fingerprints of Cannabis herbal samples, with and without pretreatment for rapid assignment to their different chemotypes by using principal component análisis (PCA) and linear discriminant analysis (LDA) [3]. (iv) To achieve the selectivity in response to trinitrotoluene (TNT) through reactive removal of interfering ions following mobility isolation using a tandem IMS with reactive stage as detection system [4]. (v) To develop a pioneer online coupling of supercritical fluid extraction (SFE) as sample introduction system (SIS) prior IMS using a column filled with Tenax TA material as sorbent trap to coupled both devices to improve analytical properties such as sensitivity and selectivity of future IMS methods [5]. (vi) To carry out a bibliographical study which gather and critically discuss recent publications related to analytical techniques to distinguish olive oils according to their quality as extra virgin (EVOO), virgin (VOO) or lampante (LOO) [6]. (vii) To investigate and compare different chemometric approaches for olive oil classification as EVOO, VOO or LOO using GC-IMS to get the most robust model over time [7]. (viii) To evaluate the combination of the results of orthogonal instrumental techniques to differentiate EVOO, VOO or LOO to imitate the expert panels [8]. (ix) To analyze olive and olive oil samples according with their production system to classify them as organic or conventional using ultraviolet (UV)-IMS, GC-IMS, GC-MS and/or capillary electrophoresis (CE)-UV [9].La espectrometría de movilidad iónica (IMS en inglés) es una técnica analítica que se basa en la separación de iones gaseosos bajo la influencia de un campo eléctrico a través de una atmósfera de gas inerte. Algunas de las principales limitaciones de la IMS, dependiendo del contexto, pueden ser la limitada capacidad de cuantificación de compuestos en muestras reales ya que se obtienen normalmente rangos lineales de cuantificación muy estrechos; la escasa selectividad debido al bajo poder de resolución de este tipo de equipos; y la dificultad de identificación de forma inequívoca de compuestos en muestras reales ya que las bases de datos existentes no están tan actualizadas como para otras tecnologías como la espectrometría de masas (MS en inglés). Por tanto, resulta evidente que existe una demanda de metodologías más selectivas y que proporcionen mayor capacidad de detección y cuantificación de analitos. Con estas premisas, se puede decir que el mayor reto actual de la IMS es maximizar la capacidad de detección de la técnica con el fin de conseguir la identificación inequívoca de un alto número de analitos. Este reto es actualmente utópico cuando se trabaja con muestras complejas. Por ello, la principal motivación de esta Tesis Doctoral fue buscar soluciones para los distintos retos a los que se enfrenta actualmente la IMS en un contexto teórico y aplicado. El objetivo básico de la investigación fue explorar el potencial de la IMS mediante el uso de estrategias teóricas y aplicadas para mejorar la capacidad de detección e identificación de los análisis realizados con esta tecnología. Estas nuevas estrategias se aplicaron a lo largo de las etapas principales del proceso analítico y permitieron mejorar características analíticas básicas, como la selectividad y la sensibilidad, de los métodos de análisis optimizados y su capacidad de detección. El logro de este objetivo básico condujo a métodos de análisis de estándares y muestras reales, como explosivos, drogas, suelo, plantas de romero, aceitunas y principalmente diferentes tipos de aceites de oliva. Este objetivo básico se dividió en tres objetivos generales de acuerdo con los diferentes temas de investigación para abordar en esta Tesis Doctoral: a) aprovechar los beneficios derivados del estudio de los aspectos teóricos de la IMS para mejorar la interpretación de los espectros de IMS y del uso de características adicionales como información estructural para mejorar el análisis cualitativo; b) desarrollar herramientas para mejorar la capacidad de detección e identificación en los análisis de IMS; y c) aprovechar las oportunidades de los instrumentos de cromatografía de gases (GC en inglés)-IMS e IMS para el análisis de alimentos como un área de aplicación en expansión en IMS basado en métodos de análisis no dirigidos. En este contexto, la Tesis ha incluido los siguientes estudios: (i) Estudiar los fundamentos de la formación de iones producto a través del modelado computacional de la estabilidad de los iones utilizando cálculos ab initio para combinarlos con los patrones espectrales y la estructura de los iones [1]. (ii) Explorar la fragmentación de iones utilizando un campo eléctrico externo y el potencial de la información adicional de estos fragmentos para mejorar las tasas de categorización por clase química utilizando redes neuronales [2]. (iii) Explorar un equipo de desorción térmica (TD en inglés)-IMS para obtener huellas espectrales de muestras de plantas de cannabis, con y sin pretratamiento, para la rápida asignación de los diferentes quimiotipos mediante análisis de componentes principales (PCA en inglés) y análisis discriminante lineal (LDA en inglés) [3]. (iv) Lograr la respuesta selectiva del trinitrotolueno (TNT en inglés) a través de la eliminación con etapa reactiva de iones interferentes usando el aislamiento de iones con un IMS en tándem con etapa reactiva como sistema de detección [4]. (v) Desarrollar un acoplamiento on-line pionero de la extracción con fluidos supercríticos (SFE en inglés) como sistema de introducción de muestra previo a la IMS utilizando una columna rellena con el material Tenax TA como trampa sorbente para acoplar ambos dispositivos para mejorar propiedades analíticas como la sensibilidad y la selectividad de futuros métodos IMS [5]. (vi) Realizar un estudio bibliográfico que reúna y discuta críticamente las publicaciones recientes relacionadas con técnicas analíticas para distinguir los aceites de oliva según su calidad como virgen extra (AOVE), virgen (AOV) o lampante (AOL) [6]. (vii) Investigar y comparar diferentes estrategias quimiométricas para la clasificación del aceite de oliva como AOVE, AOV o AOL utilizando la GC-IMS para obtener el modelo más robusto con el tiempo [7]. (viii) Evaluar la combinación de los resultados de técnicas instrumentales ortogonales para diferenciar AOVE, AOV o AOL para imitar los paneles de expertos [8]. (ix) Analizar muestras de aceitunas y aceite de oliva de acuerdo con su sistema de producción para clasificarlas como ecológicas o convencionales usando ultravioleta (UV)-IMS, GC-IMS, GC-MS y/o electroforesis capilar (CE en inglés)- UV [9]

Book of Abstracts of CEB Annual Meeting 2017

This one-day meeting is intended to bring together all CEB researchers from across the the different groups and thematic lines. We have lined up 21 oral presentations of research highlights and 59 poster communications. This meeting is also characterized by providing significant amount of time dedicated to discussion. We expect that such discussion, with the help of the external advisory board, will identify strategic issues to foster CEB competitiveness at both the national and international levels.This publication contais research works sponsored by Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Species Identification and Food Fraud Analysis in Commercial Fish Products Through DNA- based methods

Globalization of food supply chains has led to an increased uncertainty of the origin and safety of fish-based products. Barcoding can be used to validate the labelling of products and to trace their origin. “Fish fraud” has been discovered across the globe. Barcoding can also trace fish species as there can be human health hazards related to consumption of fish. The study evaluated the applicability of the mitochondrial genes cytochrome b (cytB), and cytochrome oxidase subunit I (COI) for the identification of fish and processed fish product by DNA barcoding. In the study, universal primers for mitochondrial cytB were used to discriminate fish species in raw and processed forms. The barcode primers were cross tested against collected fish product. In this study DNA barcoding was employed to identify fishery product collected from market and supermarket located in Apulia region (Southern Italy). We collected and analyses 90 samples for our study. For this project different varieties of fish samples were collected from different supermarkets and of different companies. DNA was isolated from all samples and amplified by PCR; the most intense amplified product was chosen for Sanger Sequencing. After sequencing, the sequences were matched with NCBI BLAST and FISH BOL. After obtaining the results species were identified and matched with the labelling of the products. Non-compliance between the species detected and the species declared in the label was detected in 10 out of 90 (11.1) % samples. The study provides further evidence of the need for increased traceability and assessment of food products authentication. Additionally, correct species denomination and traceability may increase the standard of management of hazards related to fish and food safety as well as ensuring product authenticity, providing reliable information to consumers. Another objective of the thesis was the development of loop-mediated isothermal amplification (LAMP) assay for rapid and direct screening of yellowfin tuna (Thunnus albacares) in commercial fish products. In this study, a loop mediated isothermal amplification (LAMP) assay was developed and validated targeting the mitochondrial cytochrome b gene for fast and direct detection of Thunnus albacares, which is a valuable species of tuna. The analytical specificity was confirmed using 18 target samples (Thunnus albacares) and 18 samples of non-target fish species. The analytical sensitivity of the LAMP assay was 540 fg DNA per reaction. In addition, a simple and direct swab method without time-consuming nucleic acid extraction procedures and the necessity for cost-intensive laboratory equipment was performed that allowed LAMP detection of Thunnus albacares samples within 13 minutes. Due to its high specificity and sensitivity, the LAMP assay can be used as a rapid and on-site screening method for the identification of Thunnus albacares, potentially providing a valuable monitoring tool for food authenticity control by the authoritie

Phenolic Compounds

Phenolics are commonly available compounds in foods, beverages, and spices. They have great importance in all aspects of daily life including industry, health, and research. As such, this book presents a comprehensive overview of phenolic compounds and their potential applications in industry, environment, and public health. Chapters cover such topics as the production of these compounds and their uses in environmental sustainability, climate change, green industry, and treatment of human disease