ELECTROCHEMICAL SENSORS FOR ASSESSMENT OF FOOD QUALITY AND SAFETY

The food industry is constantly challenged to meet consumer demands for new food products that are safe, convenient, affordable, pleasurable and healthy. Nanotechnology has begun to find potential applications in the area of functional food by engineering biological molecules toward functions very different from those they have in nature, opening up a whole new area of research and development. Of course, there seems to be no limit to what food technologists are prepared to do to our food and nanotechnology will give them a whole new set of tools to go to new extremes. The main objective of this research project was the development of analytical devices for the rapid and reliable determination of biological and chemical species (inorganic, and organic, including those of bacterial origin) present in foods of different types and origin for the assessment of food quality and safety. The project mainly focused on the development of micro- or nanosensor arrays to be used in electrochemical devices. For this purpose, it is planned to use conventional electrodes (glassy carbon, screen printed platinum, gold electrodes) and electrodes based on nanostructured materials suitably functionalized for application. In fact, it is well known that these surfaces can be modified by using chemical or biological systems to facilitate both the electron transfer at the electrode surface and the specificity and selectivity of the electrochemical transducer. Such devices, especially in the form of a complex array, are an attractive alternative over the use of expensive laboratory equipment, since they can provide reliable and quantitative information simultaneously on multiple analytes. The performance of these sensors was evaluated by using experimental and theoretical approaches based mainly on various electroanalytical techniques. Among the sensors developed in the project, those most appropriate for use as amperometric detectors in analytical systems (in flow or batch mode) will be subjected to validation studies and directly used on real samples. This phase of the project will require also the use of appropriate classical analytical instrumentation such as HPLC-UV, spectrophotometry, ELISA to assess the quality parameters of the methods developed. Nanomaterials have high surface-to-volume ratios, unique surface activities, and high electron-transfer rates at relatively low overpotentials. These characteristics make them ideal platforms for the design of electrochemical sensors. In addition, they can be chemically activated to act as immobilization surfaces that improve the stability of the attached biomaterials. Based on these considerations, the main objective of this research project is to improve the existing methodology through the development of simple analytical methods based on electrochemical nanosensors, whether single or in arrays, enabling them multi-elementary and rapid analysis of food of animal and vegetable origin and reliable determination of potentially harmful species (inorganic, and organic, including those of bacterial origin) present at trace levels in food. In research work, it is demonstrate the potentialities of nanosensors in two spheres of food-related applications: (i) nanosensors aimed at food quality control, (ii) nanosensors used for safety control in food. The present research work is thus structured in four chapters: Chapter 1 were the applicability of modified commercial sensors (screen-printed) in complex foodstuffs is demonstrated; Chapter 2 is devoted to the development and use of a nano-biosensor and modified electrode for determination of fish freshness (purine derivatives); Chapter 3 describe the use of nanostructure (carbon nanotubes such as multi-walled) for the rapid evaluation of contaminant (bisphenol A) in water bottles and baby bottles. Finally, chapter 4 is focused on the determination of the majors allergens present in peanuts (Ara h 1 and Ara h 2) using amperometric magnetoimmunosensor.