| 1. |
- Bianchi, F., et al.
(författare)
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Differentiation of the volatile profile of microbiologically contaminated canned tomatoes by dynamic headspace extraction followed by gas chromatography-mass spectrometry analysis
- 2009
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Ingår i: Talanta. - : Elsevier BV. - 0039-9140 .- 1873-3573. ; 77:3, s. 962-970
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Tidskriftsartikel (refereegranskat)abstract
- The aromatic profile of microbiologically contaminated canned tomatoes was analyzed by the dynamic headspace extraction technique coupled with gas chromatography-mass spectrometry. Canned tomatoes contaminated with Escherichia coli, Saccharomyces cerevisiae and Aspergillus carbonarius were analyzed after 2 and 7 days. About 100 volatiles were detected, among which alcohols, aldehydes and ketones were the most abundant compounds. Gas chromatographic peak areas were used for statistical purposes. First, principal component analysis was carried out in order to visualize data trends and clusters. Then, linear discriminant analysis was performed in order to detect the set of volatile compounds ables to differentiate groups of analyzed samples. Five volatile compounds, i.e. ethanol, beta-myrcene,o-methyl styrene, 6-methyl-5-hepten-2-ol and 1-octanol, were found to be able to better discriminate between uncontaminated and contaminated samples. Prediction ability of the calculated model was estimated to be 100% by the "leave-one-out" cross-validation. An electronic nose device was then used to analyze the same contaminated and not contaminated canned tomato samples. Preliminary results were compared with those obtained by dynamic headspace gas chromatography-mass spectrometry, showing a good agreement.
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| 2. |
- Concina, Isabella, et al.
(författare)
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Early detection of microbial contamination in processed tomatoes by electronic nose
- 2009
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Ingår i: Food Control. - : Elsevier BV. - 0956-7135 .- 1873-7129. ; 20:10, s. 873-880
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Tidskriftsartikel (refereegranskat)abstract
- Microbial contamination can easily affect processed tomato, thus determining both organoleptic adulterations and potential health risks for customers. Innovative techniques for a rapid and reliable diagnose of spoilage, such as electronic nose technology, are highly requested in order to guarantee food safety and to improve production. In this work canned peeled tomatoes were artificially spoiled with different kinds of microbial flora and then were analyzed by means of an electronic nose based on thin film metal oxide gas sensors. Preliminary analyses by dynamic-headspace gas chromatographic-mass spectrometry showed significant differences in the semi-quantitative volatile compounds profile of spoiled tomato samples just after few hours from contamination, thus suggesting to employ the electronic nose for an early diagnose of microbial presence. The electronic nose was indeed able to reveal contamination, even at early stages depending on the type of contaminant (e.g. for Saccharomyces cerevisiae and Escherichia coli), and to recognize spoiled tomato samples with good classification performances.
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| 3. |
- Concina, Isabella, et al.
(författare)
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Electronic Nose : A Promising Tool For Early Detection Of Alicyclobacillus spp In Soft Drinks
- 2009
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Ingår i: Olfaction and electronic nose. ; , s. 535-536
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Konferensbidrag (refereegranskat)abstract
- In the present work we investigate the potential use of the Electronic Nose EOS835 (SACMI scarl, Italy) to early detect Alicyclobacillus spp in two flavoured soft drinks. These bacteria have been acknowledged by producer companies as a major quality control target microorganisms because of their ability to survive commercial pasteurization processes and produce taint compounds in final product. Electronic Nose was able to distinguish between uncontaminated and contaminated products before the taint metabolites were identifiable by an untrained panel. Classification tests showed an excellent rate of correct classification for both drinks (from 86% no to 100%). High performance liquid chromatography analyses showed no presence of the main metabolite at a level of 200 ppb, thus confirming the skill of the Electronic Nose technology in performing an actual early diagnosis of contamination.
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| 4. |
- Vomiero, Alberto, et al.
(författare)
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Integration of metal oxide nanowires in dye sensitized solar cells
- 2009
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Ingår i: 2009 34th IEEE Photovoltaic Specialists Conference : (PVSC 2009). - Piscataway, NJ : IEEE Communications Society. - 9781424429509 ; , s. 001325-001326
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Konferensbidrag (refereegranskat)abstract
- One of the most promising architectures of third generation solar cells is integration of single crystalline nanowires as electron transporters in anodes of electrochemical cells.[1-3] The nanowire-based cells aim at significantly increase cell efficiency thanks to the higher mobility of electrons along the single crystalline lattice of the nanowires with respect to traditional polycrystalline networks, greatly reducing electron-hole recombination controllable by passivation, functionalization or coaxial coating of the nanowire. The nanonetworks have been integrated in DSCs using the traditional N719 dye and the I-3/I-3 redox couple. The functional properties of the cells under 1 sun irradiation have been compared with traditional polycrystalline TiO2 photoanodes. ©2009 IEEE.
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| 5. |
- Vomiero, Alberto, et al.
(författare)
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ZnO/ TiO2 nanonetwork as efficient photoanode in excitonic solar cells
- 2009
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 95:19
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Tidskriftsartikel (refereegranskat)abstract
- An innovative nanonetwork composed of TiO2 nanoparticles and single-crystalline ZnO nanowires is demonstrated as efficient photoanode in excitonic solar cells. Such architecture benefits of the capability of high sensitizer loading offered by the nanoparticles and of the direct conduction path for electrons guaranteed by the nanowires. The combination of these features leads to improved light absorption, electron photogeneration, and charge collection. The nanonetwork was implemented in a dye-sensitized solar-cell architecture demonstrating threefold enhancement of the efficiency with respect to a nanowire photoanode of the same thickness. Cell efficiency of 1.6% was obtained in 1.5 μm thick nanonetwork. © 2009 American Institute of Physics.
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