Compact analytical flow system for the simultaneous determination of L-lactic and L-malic in red wines

During the malolactic fermentation of red wines, L-malic acid is mainly converted to L-lactic acid. Both acids should be precisely measured during the entire process to guarantee the quality of the final wine, thus making real-time monitoring approaches of great importance in the winemaking industry. Traditional analytical methods based on laboratory procedures are currently applied and cannot be deployed on-site. In this work, we report on the design and development of a bi-parametric compact analytical flow system integrating two electrochemical biosensors that could be potentially applied in this scenario. The developed flow-system will allow for the first time the simultaneous measurement of both acids in real scenarios at the real-time and in remote way. Miniaturized thin-film platinum four-electrode chips are fabricated on silicon substrates by standard photolithographic techniques and further implemented in a polymeric fluidic structure. This includes a 15 µL flow cell together with the required fluidic channels for sample and reagent fluid management. The four-electrode chip includes counter and pseudo-reference electrodes together with two working electrodes. These are sequentially modified with electropolymerized polypyrrole membranes that entrap the specific receptors for selectively detecting both target analytes. The analytical performance of both biosensors is studied by chronoamperometry, showing a linear range from 5 × 10−6 to 1 × 10−4 M (LOD of 3.2 ± 0.3 × 10−6 M) and from 1 × 10−7 to 1 × 10−6 M (LOD of 6.7 ± 0.2 × 10−8 M) for the L-lactate and the L-malate, respectively. Both biosensors show long-term stability, retaining more than the 90% of their initial sensitivity after more than 30 days, this being a prerequisite for monitoring the whole process of the malolactic fermentation of the red wines (time between 20 and 40 days). The flow system performance is assessed with several wine samples collected during the malolactic fermentation process of three red wines, showing an excellent agreement with the results obtained with the standard method.info:eu-repo/semantics/publishedVersio

ISFET Based Microsensors for Environmental Monitoring

The use of microsensors for in-field monitoring of environmental parameters is gaining interest due to their advantages over conventional sensors. Among them microsensors based on semiconductor technology offer additional advantages such as small size, robustness, low output impedance and rapid response. Besides, the technology used allows integration of circuitry and multiple sensors in the same substrate and accordingly they can be implemented in compact probes for particular applications e.g., in situ monitoring and/or on-line measurements. In the field of microsensors for environmental applications, Ion Selective Field Effect Transistors (ISFETs) have a special interest. They are particularly helpful for measuring pH and other ions in small volumes and they can be integrated in compact flow cells for continuous measurements. In this paper the technologies used to fabricate ISFETs and a review of the role of ISFETs in the environmental field are presented

Exploiting flow-based separation techniques for sample handling in wine analysis

Wine is a fermented product consumed in a large scale all over the world that therefore has a large impact both economic and food safety terms. The analytical control of the final product is thus of high importance; it is not a simple task given that the chemical composition of wine is very variable and complex. Consequently, there is always the need for some sample pre-treatment prior to analysis. Flow-based analyses are known for their efficiency in sample manipulation and can be easily coupled to other techniques, such as separation techniques, namely membrane-based or extraction procedures. This possibility is an important step when dealing with complex matrices, such as wine samples. This review presents the state of the art of the methodologies that were developed using flow-based systems coupled to separation devices applied to wine analysis, namely membrane-based, solid, and liquid phase extraction and low pressure chromatography separations.info:eu-repo/semantics/acceptedVersio

Wine Traceability

Wine traceability is a central theme in the current world market where consumers are increasingly demanding the quality and origin of food and drink. The wine production chain and wine composition are generally controlled by different laws (International Organization of Vine and Wine (OIV), European Union (EU), and national governments) and need specific documentation. Nevertheless, wine production is subject to fraud. Consequently, the improvement of the methods applied to verify the origin and quality of wines is very important to protect wine consumers and producers. In this book, eight different papers—six research papers and two reviews—address the topic from different points of view

Implementation of Sensors and Artificial Intelligence for Environmental Hazards Assessment in Urban, Agriculture and Forestry Systems

The implementation of artificial intelligence (AI), together with robotics, sensors, sensor networks, Internet of Things (IoT), and machine/deep learning modeling, has reached the forefront of research activities, moving towards the goal of increasing the efficiency in a multitude of applications and purposes related to environmental sciences. The development and deployment of AI tools requires specific considerations, approaches, and methodologies for their effective and accurate applications. This Special Issue focused on the applications of AI to environmental systems related to hazard assessment in urban, agriculture, and forestry areas

Total antioxidant capacity tests on wine and teas

Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2019Atualmente, os antioxidantes são tidos como compostos extremamente importantes e bioativos devido aos seus muitos benefícios comprovados para a saúde. Geralmente encontrados em vegetais e frutas, os polifenóis são um grupo complexo de moléculas às quais a ciência atribui propriedades antioxidantes. O desejo da descoberta da verdadeira capacidade antioxidante de vários produtos comestíveis tem crescido com o aumento da incidência de problemas de saúde complexos relacionados com a poluição e acumulação patológica de radicais livres. Neste trabalho experimental, a capacidade antioxidante de diferentes vinhos e chás, cinco e seis variedades respetivamente, é avaliada pelo método da quimioluminescência TRAP (Parâmetro antioxidante de captura total de radicais). A decomposição do ABAP [2,2’Azobis(2-methylpropionamidine)] produz radicais livres que interagem com o luminol, levando à quimioluminescência por este induzida. A luminescência formada é então extinta pela adição de amostras de antioxidantes ao meio reacional que suprimem o fenómeno de emissão de luz por um certo período (τlag). O Trolox, um análogo do tocoferol solúvel em água, é o inibidor de referência comumente empregue em ensaios de determinação antioxidante sendo portanto empregue como padrão. Os tempos de indução obtidos foram avaliados considerando a sua proporcionalidade em relação à concentração antioxidante e ao poder de neutralização radicalar dos compostos antioxidantes presentes, resultando na determinação da capacidade antioxidante total das amostras. As atividades antioxidantes das amostras foram expressas em equivalentes de Trolox micromolares. O vinho mostrou uma atividade antioxidante significativamente mais alta quando comparado ao chá de aproximadamente 82,2%. O melhor resultado entre os chás, pertencente ao sencha, está ainda aproximadamente 25% abaixo da menor atividade antioxidante obtida para o vinho. Foram discutidas como as variedades das uvas, tempo e processos de maturação podem afetar a capacidade antioxidante dos vinhos, bem como aspetos relativos ao tratamento das safras de chá, exposição a reações de fermentação e métodos de extração. A capacidade antioxidante total avaliada pela metodologia TRAP diminuiu na ordem: Syrah>Sangiovese>Cabernet Sauvignon>Cabernet Sauvignon + Merlot>Cascinello>sencha> bancha>verde>matcha> preto>rooibos. Foi também verificado o efeito do armazenamento do chá na perda de atividade antioxidante, na qual o matcha demonstrou ser o menos afetado entre as amostras.Nowadays, antioxidants are taken as extremely important and bioactive compounds due to their many proven health benefits. Generally found in vegetables and fruits, polyphenols are a complex group of molecules to whom science has attributed antioxidant properties. The desire to uncover the true antioxidant capacity of multiple edible products has been growing with arising complex health issues related to pollution and ultimately associated with free radical’s pathological accumulation. In this experimental work, the antioxidant capacity of different wines and teas, five and six varieties, respectively, is assessed using the chemiluminescence method of total radical trapping antioxidant parameter (TRAP). ABAP [2,2’-Azobis (2methylpropionamidine)] decomposition produces free radicals that will interact with luminol, leading to luminol induced chemiluminescence. The luminescence formed is then quenched by the addition of antioxidant samples into the reaction medium which will supress the light emission phenomenon for a certain amount of time (τlag). Trolox, a water-soluble analogue of tocopherol has been reported as the gold standard reference inhibitor commonly employed in antioxidant determination assays and as such it was used as standard. The induction times obtained were evaluated regarding their proportionality towards antioxidant concentration and radical neutralization power from the antioxidant pool of compounds, resulting in the determination of the total antioxidant capacity of the given samples. The antioxidant activities of the samples were expressed as micromolar Trolox equivalents. Wine showed a significant higher antioxidant activity compared to tea of roughly 82,2%. The highest result belonging to sencha tea was still approximately 25% below the lowest wine antioxidant activity tested. Wine grapes cultivar varieties, maturation time and processes affecting antioxidant capacity were discussed as well as tea plant cultivars treatment aspects, subjection to fermentation reactions and extraction methods. Total antioxidant capacity assessed with TRAP methodology decreased in the order: Syrah > Sangiovese > Cabernet Sauvignon > Cabernet Sauvignon + Merlot > Cascinello > sencha > bancha > green > matcha > black > rooibos. Brewed tea storage effect on antioxidant activity loss was also verified in which matcha demonstrated to be the less affected among tea samples.Alma Mater Studiorum - Bologna University - FaBiT (Departamento de Farmácia e Biotecnologia

Development of electrochemical biosensors and sensors for the determination of interest analytes

Se han puesto a punto varios métodos electroquímicos para la determinación de varios analitos de interés, como lactato, cloruro, bromuro y yoduro utilizando sistemas electródicos serigrafiados (SPEs). Su bajo costo, tamaño pequeño, portabilidad para aplicaciones in situ, así como su facilidad de modificación, les confiere gran versatilidad, para ser usados como transductores en sensores y biosensores electroquímicos con gran precisión y sensibilidad en distintas matrices. Concretamente, se ha desarrollado un biosensor amperométrico para la determinación de lactato, basado en la utilización de la enzima lactato oxidasa. El biosensor ha permitido la determinación de este ácido orgánico en líquidos biológicos como saliva y sudor y en productos alimentarios como vinos. Se incluyen también estudios de los mecanismos de inhibición de las enzimas utilizadas en los biosensores. También se han puesto a punto sensores para la determinación de haluros, que han mostrado su aplicabilidad para su cuantificación en varios tipos de muestras

New analytical tools and smartphone-based devices exploiting cell-based and bioluminescence detection for environmental and diagnostic applications

The use of portable light detectors and smart supports and bioinspired materials to confine living cells and use them for field-deployable biosensors has recently attracted much attention. In particular, bioluminescent whole-cell biosensors designed to respond to different analytes or classes of analytes have been successfully implemented in portable and cost-effective analytical devices. The activity carried out during my PhD was mainly focused on the development of whole-cell bioluminescent (BL) biosensors for multi-analyte detection and their implementation into portable analytical devices for point-of-care and point-of-need applications. Thanks to the high maturity level of reporter gene technology and the availability of several bioluminescent proteins with improved features, bioluminescence smartphone-based biosensing platforms were developed exploiting highly sensitive luciferases as reporters. A 3D-printed smartphone-integrated cell biosensor based on genetically engineered human cell lines was developed for quantitative assessment of toxicity and (anti)-inflammatory activity with a simple and rapid add- and-measure procedure. Moreover, since cells in 2D cultures do not often reflect the morphology and functionality of living organisms, thus limiting the predictive value of 2D cell-based assays, we implemented 3D cell-based assays. A non-destructive real-time BL imaging assay of spheroids for longitudinal studies on 3D cell models was first developed exploiting micropatterned 96-well plate format. The assay performance was assessed using the transcriptional regulation of nuclear factor K beta response element in human embryonic kidney cells. The assay can be implemented in any laboratory equipped with basic cell culture facilities and paves the way to the development of new 3D bioluminescent cell-based assays

Recent Advances in Antioxidant Capacity Assays

This work presents a survey of the important antioxidant capacity/activity assays applied for a diversity of samples including plant extracts, foods, biological material, etc. The published materials are critically discussed, emphasizing the recent findings in the field. New and emergent antioxidant capacity assays, such as nanoparticles-based assay, are also presented. The discussion includes chemical-based methods as well as biochemical and cellular assays. Chemical methods detailed are radical/ROS-based scavenging assays (the trolox equivalent antioxidant capacity (TEAC/ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC) assays, chemiluminescence methods, total radical-trapping antioxidant parameter (TRAP), total oxy radical scavenging capacity (TOSC), and β-carotene bleaching assays), non-radical redox potential-based assays (ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), nanoparticle-based methods and electrochemical methods), metal chelation capacity and total phenolic content tests. The biochemical-based assays and in vivo assays discussed include the oxidation of low density lipoprotein (LDL), the thiobarbituric acid reactive substances (TBARS) and the cellular antioxidant activity (CAA) assays. While a direct link between the antioxidant capacity and health benefits is still a matter of debate, the antioxidant testing methodologies presented in this chapter remain valuable for the high efficiency and cost-effective evaluation of antioxidants, from compound discovery to quality control

Grapes and Wine

Grape and Wine is a collective book composed of 18 chapters that address different issues related to the technological and biotechnological management of vineyards and winemaking. It focuses on recent advances, hot topics and recurrent problems in the wine industry and aims to be helpful for the wine sector. Topics covered include pest control, pesticide management, the use of innovative technologies and biotechnologies such as non-thermal processes, gene editing and use of non-Saccharomyces, the management of instabilities such as protein haze and off-flavors such as light struck or TCAs, the use of big data technologies, and many other key concepts that make this book a powerful reference in grape and wine production. The chapters have been written by experts from universities and research centers of 9 countries, thus representing knowledge, research and know-how of many regions worldwide