Matteo Scampicchio

Nanofibrous membrane based tyrosinase-biosensor for the detection of phenolic compounds.

A tyrosinase-modified electrode is described to be used as amperometric biosensor for the detection of phenolic compounds in food. The enzyme has been immobilized by drop-coating on a glassy carbon electrode covered by a polyamidic nanofibrous membrane prepared by electrospinning. With respect to others, the selectivity of the designed tyrosinase-biosensor resulted modified by the presence of the nanostructured coating which seems to affect the permeability of phenols as a function of the pH of the solution and of their dissociation constants. The biosensor exhibits a response time of 16 s, a detection limit of 0.05 microM, and a linearity up to 100 microM (slope: -304 nA microM(-1); intercept: -191 nA, r(2)=0.996, n=19). Among others, it can be successfully used for monitoring in real time the release kinetics of phenols encapsulated in polymeric microcapsules.

Optical nanoprobes based on gold nanoparticles for sugar sensing

A novel optical nanoprobe for sugar sensing is reported. The assay used an electrospun polyamide mesh containing Au salts. The reaction of carbohydrates with these Au salts in alkaline media generates gold nanoparticles (AuNPs) at room temperature without the need for Au seeds. The optical properties of the resulting AuNPs relate to the total reducing sugar content of the samples analysed. The development of such inexpensive disposable optical nanoprobes could find applications in a host of industrial, biomedical and clinical fields.

A low-cost and low-tech electrochemical flow system for the evaluation of total phenolic content and antioxidant power of tea infusions

A disposable, small scale and low-cost electrochemical wall-jet flow-cell was build up together with a graphite lead mounted onto a pencil holder able to modulate the current response by the control of the surface area of the electrode. The total phenolic content of different types of tea infusions was determined and compared with the conventional Folin-Ciocolteau method. An index of antioxidant power was also proposed and data were compared with those obtained by the DPPH* assay.

Biocatalytic nylon nanofibrous membranes

AbstractNylon-6 nanofibrous membranes (NFM) have been prepared, characterized and used to build-up electrochemical biosensing devices. The assembly and the functioning of biocatalytic NFM are described in connection with the physical and the covalent immobilization of glucose oxidase for the detection of glucose. Effects of the enzyme loading, the mediator, the pH, the surface acidity and the kinetic of the catalysis have been thoroughly investigated. The results show that NFM allow the binding of proteins without the need for the hydrolysis step, in contrast to the nylon film. Furthermore, the high surface-to-volume ratio of the NFM allow superior loading of the enzyme with respect to thin film technology. The immobilization step does not affect the permeability of the coating to the mediator used. These results give evidence that NFM are a promising and inexpensive coating for a novel electrochemical transducer.n FigureRepresentation of the assembly of the biosensing unit and of the reactions occuring at the assembled biosensor

Sugar determination via the homogeneous reduction of Au salts: a novel optical measurement.

A novel optical assay for sugar determination based on the catalytic and biocatalytic growth of gold nanoparticles (AuNPs) is presented. The reaction of carbohydrates with these Au salts in alkaline media generates AuNPs at room temperature (RT) without the need for Au seeds in the solution or fibrous mesh. The optical properties of the resulting AuNPs relates to the total reducing sugar content of the samples analyzed. The development of such inexpensive optical assay was evaluated qualitatively and quantitatively on food beverages and honey samples. Its application can be of help to control the glucose content of the diet or easily extended in a host of industrial, biomedical and clinical fields.

Development of Food Nanostructures by Electrospinning

In this chapter, a novel technique, named electrospinning, that is increasingly used to develop nano-fibers and nano-membranes that can be used in different areas such as filter media or food processing, is described. Particular attention was devoted to the material and processing parameters that are of paramount importance in developing useful nano-fiber materials. A number of important examples of application of this technology to the food and environmental sectors are reported.

Application of the electronic nose in olive oil analyses

Publisher Summary It is possible to differentiate and classify extra virgin olive oil (EVOOs) from different geographical areas by using a commercial electronic nose and by applying multidimensional chemometric techniques. There is a growing emphasis and consensus that intelligent sensor arrays or electronic noses are most effective in the quality control of raw and manufactured products—for example, for determination of food freshness and maturity monitoring, shelf-life investigations, authenticity assessments of products and even microbial pathogen detection and environmental control. This application area is particularly important because the e-nose can be trained to recognize hazardous chemicals as well as odors. Furthermore, with respect to the human nose, the e-nose does not fatigue as easily, is less costly, and can travel easily into outer space. It also holds the promise of being much cheaper, smaller and easier to use and maintain than a mass spectrometer.

Chapter 31 Electrochemical sensors for food authentication

Publisher Summary Electronic nose and electronic tongue are particularly suitable for carrying out rapid and objective sensory measurements, which are important in food industries. They are the common electrochemical sensor systems responding to flavor/odor (volatiles) or taste (solubles), using an array of simple and non-specific sensors and a pattern recognition software system. The key principle involved in the electronic nose concept is the transfer of the total headspace of a sample to a sensor array that detects the presence of volatile compounds in the headspace and a pattern of signals is provided that are dependent on the selectivity and sensitivity of sensors and the characteristics of the volatile compounds in the headspace. Contrary to traditional analytical methods, the electrochemical sensor responses do not need and do not provide information on the nature of the compounds under investigation, but only on digital fingerprint of the typical food products. Results illustrated in this chapter, it is clear that the sensor responses of the electronic nose can be used to define the threshold of the shelf-life of Crescenza samples, honey and wine stored at different temperatures.

Olive Oil and Electronic Nose

Abstract Extra virgin olive oil (EVOO) is a typical product of the Mediterranean diet that plays a major role for its health benefits and excellent organoleptic properties linked to the peculiar chemical composition. One of the most significant improvements in the olive oil industry in recent years is the development of intelligent sensing systems, so-called “electronic noses,” that allow rapid, direct, and highly sensitive online monitoring of food aromatic profiles. In this chapter we show the capability of two commercial electronic noses based on two different working principles—metal oxide and field effect sensors array (MOS/MOSFET) and proton transfer mass spectrometry (PTR-MS)—to characterize EVOO. The capability of these two systems to analyze EVOO was verified with four different case studies that investigated: (1) the oxidation stage of EVOO during storage, discrimination of EVOO samples based on (2) MOS/MOSFET (3) PTR-MS electronic nose, and (4) process monitoring by PTR-MS.

Procedure 18 Electrochemical sensor array for the evaluation of astringency in different tea samples

Publisher Summary This chapter presents a procedure to construct a flow system with an electrochemical sensor array based on metal wires electrodes and evaluate the astringency of different tea samples. This protocol shows a simple and fast way to perform sensorial analysis by the use of a flow system equipped with a sensor array system. Eight metal electrodes are used to simulate the sensorial human stimuli and a simple multivariate analysis let to build up a regression model to evaluate the astringency of different teas. The multivariate regression analysis let to build up a model capable of describing the relationship between the analytical responses of the sensors array and astringency preference of the panel. The data confirms that there is a statistically significant relationship among the variables at the 99% confidence level. The R-squared statistic indicates that the model as fitted explains 96.2% of the variability. The adjusted R-squared statistic, which is more suitable for comparing models with different numbers of independent variables, is 94.2%. The prediction error of the model is less than 10%.