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

Potential use of electronic noses, electronic tongues and biosensors, as multisensor systems for spoilage examination in foods

Development and use of reliable and precise detecting systems in the food supply chain must be taken into account to ensure the maximum level of food safety and quality for consumers. Spoilage is a challenging concern in food safety considerations as it is a threat to public health and is seriously considered in food hygiene issues accordingly. Although some procedures and detection methods are already available for the determination ofspoilage in food products, these traditional methods have some limitations and drawbacks as they are time-consuming,labour intensive and relatively expensive. Therefore, there is an urgent need for the development of rapid, reliable, precise and non-expensive systems to be used in the food supply and production chain as monitoring devices to detect metabolic alterations in foodstuff. Attention to instrumental detection systems such as electronic noses, electronic tongues and biosensors coupled with chemometric approaches has greatly increased because they have been demonstrated as a promising alternative for the purpose of detecting and monitoring food spoilage. This paper mainly focuses on the recent developments and the application of such multisensor systems in the food industry. Furthermore, the most traditionally methods for food spoilage detection are introduced in this context as well. The challenges and future trends of the potential use of the systems are also discussed. Based on the published literature, encouraging reports demonstrate that such systems are indeed the most promising candidates for the detection and monitoring of spoilage microorganisms in different foodstuff

Electronic Noses and Tongues: Applications for the Food and Pharmaceutical Industries

The electronic nose (e-nose) is designed to crudely mimic the mammalian nose in that most contain sensors that non-selectively interact with odor molecules to produce some sort of signal that is then sent to a computer that uses multivariate statistics to determine patterns in the data. This pattern recognition is used to determine that one sample is similar or different from another based on headspace volatiles. There are different types of e-nose sensors including organic polymers, metal oxides, quartz crystal microbalance and even gas-chromatography (GC) or combined with mass spectroscopy (MS) can be used in a non-selective manner using chemical mass or patterns from a short GC column as an e-nose or “Z” nose. The electronic tongue reacts similarly to non-volatile compounds in a liquid. This review will concentrate on applications of e-nose and e-tongue technology for edible products and pharmaceutical uses

Primjena elektronskog nosa i elektronskog jezika u mljekarskoj industriji

Electronic nose (e-nose) and electronic tongue (e-tongue) instrumental systems were designed to crudely mimic human olfactory and taste sensory organs and are composed of an array of sensors. Complex data sets from electronic nose and electronic tongue signals combined with multivariate statistics represent rapid and efficient tools for classification, discrimination, recognition and identification of samples, as well as for the prediction of concentrations of different compounds. A wide variety of sensors can be employed into the design of these instrumental systems, especially that of electronic tongues, offering numerous practical applications. In this study, characteristics of sensors and possibilities of electronic nose and electronic tongue applications in the dairy industry were reviewed.Elektronski nos i elektronski jezik predstavljaju instrumentalne sustave konstruirane u svrhu reprodukcije olfaktornog i okusnog senzorskog sustava čovjeka, a čiju osnovu čini niz senzora. Kompleksni podaci signala elektronskog nosa i elektronskog jezika, upotpunjeni multivarijantnim statističkim metodama omogućuju brze i učinkovite metode klasifikacije, razlikovanja, prepoznavanja i identifikacije uzoraka a također i predviđanja koncentracija različitih sastojaka. Široki spektar različitih senzora može biti uključen u izvedbu navedenih instrumentalnih sustava, osobito u slučaju elektronskog jezika, omogućujući brojne praktične primjene. U ovom radu dan je pregled karakteristika senzora i mogućnosti primjene elektronskog nosa i elektronskog jezika u mljekarskoj industriji

Biosensor-rivi erinevate reovete biokeemilise hapnikutarbe uurimiseks

A Thesis for applying for the degree of Doctor of Philosophy in Engineering Sciences.Väitekiri filosoofiadoktori kraadi taotlemiseks tehnikateaduse erialal.The basis of all life on Earth is the existence of clean water. The state of water must be constantly monitored to ensure that the water is clean. One critical parameter in accessing water purity is the content of organic pollutants. A universal parameter - biochemical oxygen demand (BOD) – is widely used to assess this. The BOD test determines the amount of biodegradable organic compounds in wastewater. The dissolved oxygen concentration in the test sample is measured at the beginning and end of the incubation period, and the BOD value is calculated from the difference. The incubation period during which the decomposed organic matter content is measured is 5 days according to the American standard (BOD5) and 7 days according to the Swedish standard (BOD7). Such a long incubation time is a severe disadvantage of this method, as, during this time, elevated BOD can have irreversible consequences for the water body. An alternative method for measuring BOD is to use biosensors that can estimate the BOD value of the sample in minutes. A biosensor is an analytical device consisting of a biological recognition element and physicochemical transducer. BOD biosensors use microorganisms as the biological recognition element and the dissolved oxygen sensor as the transducer. The accuracy of the biosensor depends mainly on the microorganisms used. Microorganisms with a broad substrate spectrum that use different types of organic compounds for their activities provide a better match to the BOD7 value. There are several other solutions for the selection of microorganisms. Mixed bacterial cultures have a broader substrate spectrum however, their composition changes over time and causes signal instability. One possibility, when it comes to approaching these issues, is to use different bacterial cultures in a sensor array in which different cultures are spatially separated from each other. The use of spatially separated pure microbial cultures makes it possible to prevent contamination between different sensors in the array while also ensuring a longer lifetime for the sensor. Different possibilities for constructing a BOD sensor array were investigated in this work. Microchips based on various technologies were first studied, and their suitability for electrochemical measurements was tested. The experiments showed that the screen-printed electrode array was suitable for the biosensor. The biosensor array was then constructed using the bacterial culture Pseudomonas putida Pc15, and its behaviour in different solutions was investigated. It was shown that the BOD of water samples could be estimated with the obtained biosensor array. In the future, it may be feasible to measure BOD values with the sensor array consisting of several membranes that have been modified with different pure bacterial cultures.Kogu elu alus maakeral on puhta veel olemasolu. Selleks, et tagada vee puhtus tuleb selle reostustaset pidevalt jälgida. Üks oluline parameeter vee puhtuse hindamisel on orgaanilise reostuse sisaldus. Selle hindamiseks kasutatakse laialdaselt universaalset parameetrit - biokeemiline hapnikutarve ehk BHT. BHT väljendab lahustunud hapniku hulka, mis kulub vees leiduva orgaanilise aine lagundamiseks ning anorgaaniliste ühendite oksüdeerimiseks teatud aja jooksul ja kontrollitud tingimustel. Selle leidmiseks mõõdetakse lahustunud hapniku kontsentratsioon uuritavas proovis inkubatsiooniperioodi alguses ja lõpus ning nende vahe alusel arvutatakse BHT väärtus. Inkubatsiooniperiood, mille vältel lagunenud orgaanilise aine sisaldust mõõdetakse on vastavalt Ameerika standardile 5 päeva (BHT5) ning Rootsi standardile 7 päeva (BHT7). Nii pikk inkubatsiooniaeg on antud meetodi puhul tõsiseks puuduseks, sest sellise aja jooksul võivad kõrgenenud BHT-l olla veekogule pöördumatud tagajärjed. Alternatiivse võimalusena kiiremaks BHT määramiseks on mikroorganismidel baseeruvad biosensorid, mis võimaldavad anda hinnangu proovi BHT kohta minutitega. Biosensor on analüütiline seade, mis koosneb bioloogilisest äratundmiselemendist ja signaali muundurist. BHT biosensorites kasutatakse bioloogilise äratundmissüsteemina mikroorganisme ja muundurina lahustunud hapniku andurit. Biosensori mõõtetäpsus sõltub suuresti kasutatud mikroorganismidest. Parema kokkulangevuse BHT7 väärtusega tagavad laia substraadispektriga mikroorganismid, mis kasutavad oma elutegevuseks erinevaid tüüpe orgaanilisi ühendeid. Mikroorganismide valikuks on mitmeid erinevaid lahendusi. Kuigi mikroobide segude kasutamisega saavutatakse lai substraadispekter ja tundlik sensor, on antud sensorid lühikese kasutuseaga ja ebastabiilsed kuna mikroorganismide kooslus membraanis muutub pidevalt. Selle vältimiseks on võimalik kasutada puhaskultuuridel põhinevaid sensor-rivisid, mis koosnevad paljudest erinevatest biosensoritest ning kus erinevad mikroorganismide kultuurid on omavahel ruumiliselt eraldatud. Antud töös uuriti erinevaid võimalusi BHT sensor-rivi koostamiseks. Selleks uuriti esmalt erinevatel tehnoloogiatel põhinevaid mikrokiipe ning iseloomustati nende sobivust teostades erinevaid elektrokeemilisi mõõtmisi. Katsete tulemusena osutus sobivaks siiditrüki meetodil valmistatud sensor-rivi kiip. Järgnevalt koostati biosensor rivi kasutades bakterikultuuri Pseudomonas putida Pc15 ja uuriti selle käitumist erinevates lahustes. Doktoritöö tulemusena leiti, et antud põhimõtet on võimalik kasutada sensor-rivide valmistamisel ning saadud biosensor-rividega on võimalik hinnata veeproovide BHT-d. Edasistes uuringutes tuleks uurida erinevate, ruumiliselt eraldatud bakterkultuuride samaaegset kasutamist sensor-rivis.Publication of this thesis is supported by the Estonian University of Life Sciences. This study has been supported by Doctoral School of Energy and Geotechnology III (Estonian University of Life Sciences ASTRA project “Value-chain based bio-economy”), European Regional Development Fund and Archimedes Foundation

Electronic sensor technologies in monitoring quality of tea: A review

Tea, after water, is the most frequently consumed beverage in the world. The fermentation of tea leaves has a pivotal role in its quality and is usually monitored using the laboratory analytical instruments and olfactory perception of tea tasters. Developing electronic sensing platforms (ESPs), in terms of an electronic nose (e-nose), electronic tongue (e-tongue), and electronic eye (e-eye) equipped with progressive data processing algorithms, not only can accurately accelerate the consumer-based sensory quality assessment of tea, but also can define new standards for this bioactive product, to meet worldwide market demand. Using the complex data sets from electronic signals integrated with multivariate statistics can, thus, contribute to quality prediction and discrimination. The latest achievements and available solutions, to solve future problems and for easy and accurate real-time analysis of the sensory-chemical properties of tea and its products, are reviewed using bio-mimicking ESPs. These advanced sensing technologies, which measure the aroma, taste, and color profiles and input the data into mathematical classification algorithms, can discriminate different teas based on their price, geographical origins, harvest, fermentation, storage times, quality grades, and adulteration ratio. Although voltammetric and fluorescent sensor arrays are emerging for designing e-tongue systems, potentiometric electrodes are more often employed to monitor the taste profiles of tea. The use of a feature-level fusion strategy can significantly improve the efficiency and accuracy of prediction models, accompanied by the pattern recognition associations between the sensory properties and biochemical profiles of tea

Rapid and innovative instrumental approaches for quality and authenticity of olive oils

The quality of virgin olive oils is assessed through the determination of several analytical parameters, whose values must be within the ranges established by the different institutions involved. In addition to official methods, there is a strong need for simple, rapid, and environmentally friendly techniques for the quality control of virgin olive oils and for addressing the challenging task of determining geographical origin and detecting adulterants. Toward this purpose, some of the most interesting applications based on optical spectroscopic techniques, on the measurement of electrical characteristics and on the use of instruments equipped with electronic chemical sensors, including also other promising techniques are herein discussed. These techniques, adequately coupled with an appropriate statistical approach, appear to be promising for assessment of several quality-related parameters. The prediction of sensory attributes and of the oxidative status of virgin olive oils have also been reviewed by adopting these selected techniques, which are also considered to be potentially appropriate solutions for identification of the geographical origin of virgin olive oils and to assess their adulteration with cheaper oils. Overall, the techniques discussed are promising and cutting-edge approaches for the establishment of useful portable instruments for in situ monitoring of the quality of virgin olive oils. Practical applications: The simple, rapid, and environmentally friendly analytical approaches discussed herein represent promising analytical tools for assuring the authenticity and monitoring the quality of virgin olive oils. Such innovative techniques and tools need to be ring-tested and validated. Some innovative reviewed approaches will permit to develop useful portable instruments able to perform in situ appropriate controls also by small laboratories or olive oil mills with limited technical facilities. These equipments will be potentially usable also by trained \u201cnon-professional analytical skilled\u201d people. Some other approaches, rapid but more expensive, will be applicable mainly by quality control labs and will increase the number of samples analyzed per day, thus fostering laboratory proficiency and an effective fighting against olive oil fraud

Cyclodextrins for oral liquid paediatric drug delivery: Application to corticosteroids

In the present research, the ability of cyclodextrins (CDs) to solubilise and taste mask poorly soluble bitter drugs was assessed by various analytical techniques, including a novel in vitro taste analyser, to propose CDs as excipients for oral liquid paediatric formulations. Corticosteroids were selected as model drugs because of their relevance in paediatrics, whilst model bitter drug quinine was also selected to provide comparative data. Aside from various inclusion complex characteristics, such as stability constants and complexation efficiencies, phase solubility studies determined that: the CDs formed soluble 1:1 inclusion complexes with the corticosteroids studied, the CD derivatives were capable of providing adequate paediatric dose volumes, simulated media in vivo and pH did not to have a major influence on inclusion complexation. The presence of preservatives, however, reduced CD solubility efficiency, whilst reducing the preservative efficiency. ITC studies determined that inclusion complexation with corticosteroids was a spontaneous process and various interactions involved with complexation were proposed. 1H NMR spectroscopy studies indicated that CDs formed inclusion complexes with the corticosteroids, whereby the drug molecules entered the CD cavities via the wider cavity opening. Human taste panel studies demonstrated that CDs were able to taste mask corticosteroids, often more efficiently than traditional taste masking agents, and with 10 times more drug being incorporated in the formulation. Excess CD was also observed to be more efficient at taste masking corticosteroids than molar equivalent concentrations. From these taste panel results, a mechanism of CD taste masking was proposed. Preliminary electronic tongue analysis was found to be able to select concentrations of various taste masking agents for subsequent taste masking assessment. Nevertheless, little correlation was found between the assessment of the electronic tongue and the human taste panel, thus limiting the legitimacy of the instrument for this application. This research has shown that CDs could be utilised in oral liquid paediatric formulations to provide dose uniformity, appropriate volume, and acceptable palatability for poorly soluble bitter drugs. Further work is required to examine the acceptability & bioavailability of these formulations in paediatric patients