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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

Analisi degli effetti degli interventi agronomici all’impianto in un intervento di recupero ambientale di una cava di sabbie ed argille della collina bolognese: parametrizzazione e quantificazione dell’azoto. / Analysis of the effects of the initial agronomic management in an intervention of environmental restoration of a sandy-claily quarry located on the Bologna hills: Parametrization and nitrogen assesment.

Almeida De Mendonca, Maria De Jesus <1977> 16 April 2012 (has links)
In questo lavoro sono state analizzate diverse strategie di recupero di una cava dismessa situata presso la località Colombara (Monte San Pietro, Bologna). Su questi terreni sono state condotte tre prove, costituite da diverse parcelle nelle quali sono stati adottati differenti trattamenti. Sono state svolte analisi di tipo quantitativo del suolo e della parte epigea delle specie arbustive e arboree, focalizzandosi sull'azoto (N totale, ammoniacale, nitrico, e firma isotopica) e sulla sostanza organica del suolo. Inoltre è stata effettuata un'indagine qualitativa della composizione floristica. Scopo della tesi è quello di individuare le strategie più efficaci per un recupero di suoli degradati. Non sempre a trattamenti iniziali migliori corrispondono i migliori risultati portando a conclusioni apparentemente controintuitive a cui si è cercato di dare risposta. / In this work we have analyzed different restoration strategies of an abandoned quarry located at Colombara (Monte San Pietro, Bologna, Italy). On these surfaces we carried out three experiments, based on manifold land parcels on which different agronomic treatments were applied. On was conducted analyses of soil and of the aboveground plant biomass of shrub and tree species. We focused on soil and leaf Nitrogen content and on the soil organic Carbon in order to evaluate the soil fertility. Moreover we carried out a qualitative analysis about the botany species composition. The main scope of this thesis was to find out the most suitable strategies to restore degraded soils. Just few times the best results correspond to better initial treatments. The latter brought to apparently counter intuitive conclusions to which we tried to find the causes.
252

Fusarium species responsible for mycotoxin production in wheat crop: involvement in food safety

Alkadri, Dima <1979> 14 June 2012 (has links)
Fusarium Head Blight (FHB) is a worldwide cereal disease responsible of significant yield reduction, inferior grain quality, and mycotoxin accumulation. Fusarium graminearum and F. culmorum are the prevalent causal agents. FHB has been endemic in Italy since 1995, while there are no records about its presence in Syria. Forty-eight and forty-six wheat kernel samples were collected from different localities and analyzed for fungal presence and mycotoxin contamination. Fusarium strains were identified morphologically but the molecular confirmation was performed only for some species. Further differentiation of the chemotypes for trichothecene synthesis by F. graminearum and F. culmorum strains was conducted by PCR assays. Fusarium spp. were present in 62.5% of Syrian samples. 3Acetyl-Deoxynivalenol and nivalenol chemotypes were found in F. culmorum whilst all F. graminearum strains belonged to NIV chemotype. Italian samples were infected with Fusarium spp for 67.4%. 15Ac-DON was the prevalent chemotype in F. graminearum, while 3Ac-DON chemotype was detected in F. culmorum. The 60 Syrian Fusarium strains tested for mycotoxin production by HPLC-MS/MS have shown the prevalence of zearalenone while the emerging mycotoxins were almost absent. The analysis of the different Syrian and Italian samples of wheat kernels for their mycotoxin content showed that Syrian kernels were mainly contaminated with storage mycotoxins, aflatoxins and ochratoxin whilst Italian grains with mainly Fusarium mycotoxins. The aggressiveness of several Syrian F. culmorum isolates was estimated using three different assays: floret inoculation in growth chamber, ear inoculation in the field and a validated new Petri-dish test. The study of the behaviour of different Syrian wheat cultivars, grown under different conditions, has revealed that Jory is a FHB Syrian tolerant cultivar. This is the first study in Syria on Fusarium spp. associated to FHB, Fusarium mycotoxin producers and grain quality.
253

Development of instrumental and sensory analytical methods of food obtained by traditional and emerging technologies

Comandini, Patrizia <1983> 25 May 2012 (has links)
The consumer demand for natural, minimally processed, fresh like and functional food has lead to an increasing interest in emerging technologies. The aim of this PhD project was to study three innovative food processing technologies currently used in the food sector. Ultrasound-assisted freezing, vacuum impregnation and pulsed electric field have been investigated through laboratory scale systems and semi-industrial pilot plants. Furthermore, analytical and sensory techniques have been developed to evaluate the quality of food and vegetable matrix obtained by traditional and emerging processes. Ultrasound was found to be a valuable technique to improve the freezing process of potatoes, anticipating the beginning of the nucleation process, mainly when applied during the supercooling phase. A study of the effects of pulsed electric fields on phenol and enzymatic profile of melon juice has been realized and the statistical treatment of data was carried out through a response surface method. Next, flavour enrichment of apple sticks has been realized applying different techniques, as atmospheric, vacuum, ultrasound technologies and their combinations. The second section of the thesis deals with the development of analytical methods for the discrimination and quantification of phenol compounds in vegetable matrix, as chestnut bark extracts and olive mill waste water. The management of waste disposal in mill sector has been approached with the aim of reducing the amount of waste, and at the same time recovering valuable by-products, to be used in different industrial sectors. Finally, the sensory analysis of boiled potatoes has been carried out through the development of a quantitative descriptive procedure for the study of Italian and Mexican potato varieties. An update on flavour development in fresh and cooked potatoes has been realized and a sensory glossary, including general and specific definitions related to organic products, used in the European project Ecropolis, has been drafted.
254

Individuazione e caratterizzazione dei prodotti di degradazione ossidativa dei secoiridoidi nell'olio vergine di oliva mediante tecniche analitiche innovative / Identification and characterization of oxidative degradation products of secoiridoids in virgin olive oil by innovative analytical techniques.

Di Maio, Ilona <1979> 24 May 2012 (has links)
Lo scopo di questo lavoro di tesi è la caratterizzazione dei prodotti di ossidazione di diversi fenoli idrofili contenuti nell’olio vergine d’oliva come idrossitirosolo, tirosolo e la forma dialdeidica dell’acido decarbossimetil elenolico legato all’idrossitirosolo, e la loro identificazione nel prodotto durante la conservazione. L’obiettivo della ricerca è trovare degli indici analitici che possono essere usati sia come marker di “freschezza” dell’olio vergine di oliva sia nella valutazione della “shelf life” del prodotto stesso. Due sistemi di ossidazione sono stati usati per ossidare le molecole sopracitate: ossidazione enzimatica e ossidazione di Fenton. I prodotti di ossidazione sono stati identificati come chinoni, dimeri e acidi. / The aim of this research is the characterization of the oxidation products of several hydrophilic phenols of virgin olive oil (VOO), such as hydroxytyrosol (3,4-DHPEA), tyrosol (p-HPEA) and dialdehydic form of decarboxymethyl elenolic acid linked to 3,4-DHPEA (3,4-DHPEA-EDA) and, their identification in the product during storage. This work is aimed at finding analytical indicators that can be used both as molecular markers of VOO “freshness” and for the evaluation of the shelf life of the product itself. Two oxidation systems were examined for the oxidation of p-HPEA, 3,4-DHPEA and 3,4-DHPEA-EDA: enzymatic oxidation and Fenton oxidation. Reaction products were identified as quinones, dimers, and acids.
255

LCA-GIS Integrated approach for a Sustainable Land Use Under Energy Crops

Di Virgilio, Nicola <1977> 14 June 2012 (has links)
In genere, negli studi di vocazionalità delle colture, vengono presi in considerazione solo variabili ambientali pedo-climatiche. La coltivazione di una coltura comporta anche un impatto ambientale derivante dalle pratiche agronomiche ed il territorio può essere più o meno sensibile a questi impatti in base alla sua vulnerabilità. In questo studio si vuole sviluppare una metodologia per relazionare spazialmente l’impatto delle colture con le caratteristiche sito specifiche del territorio in modo da considerare anche questo aspetto nell’allocazione negli studi di vocazionalità. LCA è stato utilizzato per quantificare diversi impatti di alcune colture erbacee alimentari e da energia, relazionati a mappe di vulnerabilità costruite con l’utilizzo di GIS, attraverso il calcolo di coefficienti di rischio di allocazione per ogni combinazione coltura-area vulnerabile. Le colture energetiche sono state considerate come un uso alternativo del suolo per diminuire l’impatto ambientale. Il caso studio ha mostrato che l’allocazione delle colture può essere diversa in base al tipo e al numero di impatti considerati. Il risultato sono delle mappe in cui sono riportate le distribuzioni ottimali delle colture al fine di minimizzare gli impatti, rispetto a mais e grano, due colture alimentari importanti nell’area di studio. Le colture con l’impatto più alto dovrebbero essere coltivate nelle aree a vulnerabilità bassa, e viceversa. Se il rischio ambientale è la priorità, mais, colza, grano, girasole, e sorgo da fibra dovrebbero essere coltivate solo nelle aree a vulnerabilità bassa o moderata, mentre, le colture energetiche erbacee perenni, come il panico, potrebbero essere coltivate anche nelle aree a vulnerabilità alta, rappresentando cosi una opportunità per aumentare la sostenibilità di uso del suolo rurale. Lo strumento LCA-GIS inoltre, integrato con mappe di uso attuale del suolo, può aiutare a valutarne il suo grado di sostenibilità ambientale. / Usually, when dealing with land suitability studies for crops, only environmental pedo-climatic factors are used. Crop production chain also means impact due to agronomic practices and the environment can be sensible to them basing on the site-specific vulnerability. This study wanted to define a method to spatially relate crop impacts to the environment and then to include it in land suitability procedures. LCA was used to estimate impact indicators of few herbaceous food and energy crops, and were combined with vulnerability maps defined using GIS, through the calculation of “allocation risk” values for each crop-vulnerable land combination. Energy crops were considered as an alternative land use to potentially increase the environmental sustainability. The case-study showed that crop allocation to minimize environmental risks may change basing on considered impact indicators. Methods for merging several impacts in one map were also defined. Results were as optimal crop land allocation maps combining several crops compared with conventional cropping systems, e.g. maize/wheat rotation: crops with higher impacts can be allocated in lower vulnerable lands, and vice versa. If impact risk is a priority, maize, rapeseed, wheat, sunflower and fibre sorghum should be grown only in low or moderate vulnerable lands, while perennial grasses can be grown in all areas, thus representing a possible solution to increase the sustainability of the rural land use. Developed LCA-GIS approach represents an innovative and useful decision support systems (DSS) for minimizing impacts for the environment when allocating crops. Also it represented a useful tool for understanding the sustainability of current land use by integrating it with crop statistics and land use maps.
256

Physico-chemical and microstructural properties of food dispersions

Glicerina, Virginia Teresa <1979> 29 May 2014 (has links)
The macroscopic properties of oily food dispersions, such as rheology, mechanical strength, sensory attributes (e.g. mouth feel, texture and even flavour release) and as well as engineering properties are strongly determined by their microstructure, that is considered a key parameter in the understanding of the foods behaviour . In particular the rheological properties of these matrices are largely influenced by their processing techniques, particle size distribution and composition of ingredients. During chocolate manufacturing, mixtures of sugar, cocoa and fat are heated, cooled, pressurized and refined. These steps not only affect particle size reduction, but also break agglomerates and distribute lipid and lecithin-coated particles through the continuous phase, this considerably modify the microstructure of final chocolate. The interactions between the suspended particles and the continuous phase provide information about the existing network and consequently can be associated to the properties and characteristics of the final dispersions. Moreover since the macroscopic properties of food materials, are strongly determined by their microstructure, the evaluation and study of the microstructural characteristics, can be very important for a through understanding of the food matrices characteristics and to get detailed information on their complexity. The aim of this study was investigate the influence of formulation and each process step on the microstructural properties of: chocolate type model systems, dark milk and white chocolate types, and cocoa creams. At the same time the relationships between microstructural changes and the resulting physico-chemical properties of: chocolate type dispersions model systems dark milk and white chocolate were investigated. / Le proprietà macroscopiche di dispersioni alimentari a base oleosa tra cui quelle reologiche, meccaniche e sensoriali (consistenza, texture, palatabilità, viscosità, stabilità fisica, ecc.) sono fortemente influenzate dalla loro microstruttura che è considerata un parametro chiave nella comprensione del “comportamento macroscopico” degli alimenti. In particolar modo le proprietà reologiche di tali matrici alimentari sono direttamente influenzate sia dalla formulazione che dal processo di produzione. Durante la produzione di cioccolato e/o surrogati a base di cacao, miscele di zucchero, cacao e grassi vengono riscaldate, raffreddate, pressurizzate e raffinate (Beckett 2000). Questi operazioni tecnologiche la contribuiscono a ridurre la dimensione delle particelle, a rompere gli agglomerati e a distribuire grassi e lecitina attorno alle singole particelle, modificandone la loro microstruttura . Poiché le proprietà macroscopiche di tali matrici alimentari sono fortemente determinate dalla loro microstruttura, la valutazione delle caratteristiche microstrutturali risulta essere molto importante al fine di studiare e ottenere dettagliate informazioni sulla loro complessità. Il presente studio si è proposto pertanto di valutare, mediante tecniche dirette di microscopia ed indirette di laser light diffraction, l’influenza delle diverse formulazioni e di ogni singola fase del processo produttivo sulle proprietà microstrutturali di: sistemi modello a base oleosa, cioccolato fondente, al latte e bianco e surrogati a base di cacao. Parallelamente sono state investigate le relazioni esistenti tra le caratteristiche micro strutturali delle suddette matrici e le loro proprietà reologiche e chimico-fisiche.
257

Sensory and instrumental profiling of apples: a new tool for quality assessment

Corollaro, Maria Laura <1985> 08 May 2014 (has links)
Food suppliers currently measure apple quality considering basic pomological descriptors. Sensory analysis is expensive, does not permit to analyse many samples, and cannot be implemented for measuring quality properties in real time. However, sensory analysis is the best way to precisely describe food eating quality, since it is able to define, measure, and explain what is really perceivable by human senses and using a language that closely reflects the consumers’ perception. On the basis of such observations, we developed a detailed protocol for apple sensory profiling by descriptive sensory analysis and instrumental measurements. The collected sensory data were validated by applying rigorous scientific criteria for sensory analysis. The method was then applied for studying sensory properties of apples and their changes in relation to different pre- and post-harvest factors affecting fruit quality, and demonstrated to be able to discriminate fruit varieties and to highlight differences in terms of sensory properties. The instrumental measurements confirmed such results. Moreover, the correlation between sensory and instrumental data was studied, and a new effective approach was defined for the reliable prediction of sensory properties by instrumental characterisation. It is therefore possible to propose the application of this sensory-instrumental tool to all the stakeholders involved in apple production and marketing, to have a reliable description of apple fruit quality.
258

Using national FADN database to describe Italian farms and arable fields. A comparison of sustainability level between organic versus conventional regimes.

Albertazzi, Sergio <1985> 27 May 2014 (has links)
The study defines a new farm classification and identifies the arable land management. These aspects and several indicators are taken into account to estimate the sustainability level of farms, for organic and conventional regimes. The data source is Italian Farm Account Data Network (RICA) for years 2007-2011, which samples structural and economical information. An environmental data has been added to the previous one to better describe the farm context. The new farm classification describes holding by general informations and farm structure. The general information are: adopted regime and farm location in terms of administrative region, slope and phyto-climatic zone. The farm structures describe the presence of main productive processes and land covers, which are recorded by FADN database. The farms, grouped by homogeneous farm structure or farm typology, are evaluated in terms of sustainability. The farm model MAD has been used to estimate a list of indicators. They describe especially environmental and economical areas of sustainability. Finally arable lands are taken into account to identify arable land managements and crop rotations. Each arable land has been classified by crop pattern. Then crop rotation management has been analysed by spatial and temporal approaches. The analysis reports a high variability inside regimes. The farm structure influences indicators level more than regimes, and it is not always possible to compare the two regimes. However some differences between organic and conventional agriculture have been found. Organic farm structures report different frequency and geographical location than conventional ones. Also different connections among arable lands and farm structures have been identified.
259

Milk and dairy products: evaluation of bioactive components by analytical techniques

Guerra, Elena <1984> 29 May 2014 (has links)
Milk and dairy products are important source of bioactive compounds useful to satisfy the nutritional and physiological needs of any newborns of mammalian species and useful to guarantee adequate growth and development of infants as well as provide a complete nourishment of adults. Physico-chemical, nutritional and organoleptic properties of the main constituents and the “minor” components have a crucial role in the quality of milk and milk products. Although in the past decades dietary milk fat was often regarded as harmful for the human health, recent researches suggest that milk contains specific fatty acids with nutritional and physiological health benefits. For these reasons, a major attention is given to the quantity and quality of total fat intake. In the recent years, as a result of the new concept of multifunctional agriculture and the changing behaviours about diet, consumer demands in favor of high-quality, security and safety dairy products are increased. Moreover, milk proteins and milk-derived bioactive peptides are recognized to have a high nutritive value, several health-promoting functional activities and excellent technological properties. Accordingly, growing interest in the development of functional dairy products and preparation of infant formulae for babies who cannot be breast-fed, has been give in order to meet the specific consumer’s requests. This manuscript presents the main results obtained during my PhD research aimed to evaluate the main bioactive lipids and proteins in milk and dairy products using innovative analytical techniques. The experimental section of this manuscript is divided in two sections where are reported the main results obtained during my research activities on dairy products and human milks in order to characterize their bioactive compounds for functional food applications.
260

New associations between native parasitoids and exotic insects introduced in Italy and in Europe / Nuove associazioni tra parassitoidi indigeni e insetti esotici neointrodotti in Italia ed in Europa

Francati, Santolo <1979> 13 June 2013 (has links)
The introduction of exotic species is one of the most important threats to biodiversity.This phenomenon may cause economic and environmental damage. To prevent these invasions there are institutions like EPPO. Nevertheless, the introduction of exotic pests is an increasing issue, difficult to control. Classic biological control, based on importation of natural enemies from the country of origin, has been successfully used for over 120 years, but it has also raised some criticism. My research work has focused on the study of the new associations occurring between indigenous parasitoids and three exotic pests introduced in Italy and Europe. The three target insects considered were: Cacyreus marshalli Butler (Lepidoptera: Lycaenidae), a pest of Geranium plants; Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), a plague of Castanea sp. and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). This ladybug has been introduced as a biological control agent, but since some years it considered as an invasive species. For C. marshalli I performed laboratory tests on acceptance and suitability of immature stages of this butterfly by Exorista larvarum (Diptera: Tachinidae) and Brachymeria tibialis (Hymenoptera: Chalcidicae). The experiments showed that these two parasitoids could be used to contain this pest. For D. kuriphilus I performed field samplings in an infested chestnut area, the samples were maintained in rearing chamber until gall wasp or parasitoids emergence. In the 3-year research many parasitoids of gall wasps were found; one of these, Torymus flavipes (Walker), was found in large number. For H. axyridis the research work included a first phase of field sampling, during which I searched indigenous parasitoids which had adapted to this new host; the only species found was Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae). Laboratory tests were performed on the wasp rearing, biology and capacity to contain H. axyridis. / L'introduzione di specie esotiche è una delle minacce più importanti per la biodiversità, tale fenomeno può causare danni economici e ambientali. Anche per controllare queste introduzioni sono state create apposite istituzioni come EPPO. Tuttavia, l'introduzione di insetti esotici nocivi è un problema crescente, difficile da contrastare. Il controllo biologico classico, basato sull’introduzione dei nemici naturali dal paese di origine, è stato utilizzato con successo per oltre 120 anni, ma ha anche sollevato alcune critiche. Il mio lavoro di ricerca è stato incentrato sullo studio delle nuove associazioni tra parassitoidi indigeni e tre insetti esotici introdotti in Italia e in Europa. I tre insetti studiati sono stati: Cacyreus marshalli Butler (Lepidoptera: Lycaenidae), nocivo per le piante di Geranium; Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), dannoso al castagno e Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), coccinellide introdotto come agente di controllo biologico, ma da alcuni anni considerato come invasivo. Per C. marshalli sono stati effettuati degli esperimenti di laboratorio sulla accettabilità e l’idoneità di questo lepidottero da parte dei parassitoidi Exorista larvarum (Diptera: Tachinidae) e Brachymeria tibialis (Hymenoptera: Chalcididae). Gli esperimenti hanno dimostrato come questi due parassitoidi possano essere impiegati per il contenimento di questa specie. Per D. kuriphilus sono stati effettuati dei campionamenti in un castagneto infestato, i campioni sono stati mantenuti in celle climatizzate fino allo sfarfallamento del galligeno o dei parassitoidi. In tre anni di ricerca sono stati ritrovati molti parassitoidi, uno dei quali, Torymus flavipes (Walker), è stato rinvenuto in elevato numero. Per H. axyridis le ricerche prevedevano una fase di campo, per ricercare eventuali parassitoidi adattatisi a questo nuovo ospite; l’unica specie ritrovata è stata Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae). Con questa specie sono stati effettuati test per comprendere la sua biologia e la sua capacità di contenimento di H. axyridis, oltre che per migliorare le tecniche di allevamento.

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