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Lipid quality and oxidative stability in food products from animal origin, as affected by breeding factor / Influenza dei fattori e delle metodologie di allevamento sulle caratteristiche qualitative e sulla stabilità dei prodotti di origine animaleFunaro, Antonietta <1982> 24 May 2013 (has links)
Nowadays it is requested more investigations on alternative rearing systems that are able to improve poultry welfare and to warrant high-quality and safe meat products. This thesis work was focused on the evaluation of the oxidative stability of poultry meats, obtained with different rearing systems, diets (supplemented with bioactive compounds), and packaging conditions.
The thesis work was divided into the following parts:
- Evaluation of the effects of different rearing systems on the quality, fatty acid composition and oxidative stability of poultry thigh and breast meat belonging to different product categories (“rotisserie” and “cut-up” carcasses);
- Evaluation of the effects of different rearing systems and packaging conditions on the shelf-life of poultry thigh meat stored at 4°C for 14 days, and the effects of feed supplementation with thymol (control diet and diet with 2 different concentration of thymol) and packaging conditions on lipid oxidation of poultry thigh meat shelf-life (stored at 4°C for 14 days). The oxidative stability of poultry meat was studied by means of the spectrophotometric determinations of peroxide value and thiobarbituric acid reactive substances.
- Evaluation of anti-inflammatory effects of different flavonoids (thymol, luteolin, tangeretin, sulforaphane, polymethoxyflavones, curcumin derivates) to detect their biological activity in LPS-stimulated RAW 264.7 macrophage cells in vitro, in order to study more in depth their action mechanisms. It was evaluated the cell vitality (MTT assay), nitrite concentration and protein profile. The study was focused on the identification of potential dietary bioactive compounds in order to investigate their biological activity and possible synergic effects, and to develop new suitable strategies for long-term promotion of human health, in particular against cancer. / Oggigiorno sono sempre più richiesti i lavori di ricerca sullo studio di sistemi di allevamento alternativi in grado di migliorare il benessere degli animali e di migliorare la qualità e la sicurezza delle carni. Il presente elaborato di tesi si è basato sulla valutazione dello stato ossidativo di carni avicole, provenienti da animali allevati con sistemi alternativi ed alimentati con diete integrate con composti bioattivi, e conservate in diverse tipologie di packaging. L’organizzazione della ricerca si è sviluppata nei seguenti punti:
- Valutazione dell’effetto di sistemi di allevamento alternativi del pollo da carne sulla qualità, composizione degli acidi grassi e stabilità ossidativa della frazione lipidica muscolare delle carni di petto e coscia ottenute da due categorie commerciali (“Rotisserie” e “Cut-up”);
- Studio della stabilità ossidativa condotta mediante prove di shelf-life su carni di coscia ottenute da polli allevati con diversi sistemi di allevamento e alimentati con tre tipi di diete (dieta di controllo e diete arricchite di timolo a due diverse concentrazioni). Queste carni sono state confezionate con diverse modalità (atmosfera ordinaria e protettiva) e conservate in condizioni di refrigerazione (2-4°C) per 14 giorni. La stabilità ossidativa è stata valutata mediante le determinazioni spettrofotometriche del numero di perossidi e delle sostanze reattive all’acido tiobarbiturico;
- Valutazione dell’attività anti-infiammatoria di diversi bioflavonoidi (timolo, luteolina, tangeretina, sulforafano, polimetossiflavoni, derivati della curcumina), facendo luce sui meccanismi d’azione di quest’ultimi, su linee cellulari macrofagiche (LPS-stimulated RAW 264.7 cells) in vitro. Sono stati valutati la vitalità cellulare (MTT assay), la determinazione indiretta dell’ossido nitrico e l’identificazione delle proteine. In particolare, il lavoro si è soffermato sull’identificazione di potenziali componenti nutraceutici, caratterizzati da una forte azione sinergica, con lo scopo di indagare sulla loro attività biologica ed i loro possibili effetti sinergici e quindi di sviluppare nuove strategie finalizzate alla prevenzione del cancro, a lungo termine.
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Development of guidelines for microbiological control in microbrewery / Sviluppo di linee guida per il controlloo microbiologico nelle microbirrerieMoretti, Elio <1983> 23 May 2013 (has links)
Over the past 15 years the Italian brewing scene showed interesting changes, especially with regard to the creation of many breweries with an annual production of less than 10,000 hectoliters.
The beers produced by microbreweries are very susceptible to attack by spoilage micro-organisms that cause the deterioration of beer quality characteristics.
In addition, most of the microbreweries do not practice heat treatments of stabilization and do not carry out quality checks on the product. The high presence of beer spoilage bacteria is an economic problem for the brewing industry because it can damage the brand and it causes high costs of product retrieval.
This thesis project was aimed to study the management of the production process in the Italian microbreweries within a production less than 10,000 hl.
In particular, the annual production, type of plant, yeast management, process management, cleaning and sanitizing of a representative sample of microbreweries were investigated.
Furthermore was made a collection of samples in order to identify, with simple methods, what are spoilage bacteria more present in the Italian craft beers.
21% of the beers analysed were positive at the presence of lactic acid bacteria. These analytical data show the importance of understanding what are the weak points of the production process that cause the development of spoilage bacteria.
Finally, the thesis examined the actual production of two microbreweries in order to understand the process management that can promote the growth of spoilage bacteria in beer and production plant.
The analysis of the data for the two case studies was helpful to understand what are the critical points where the microorganisms are most frequently in contact with the product. The hygiene practices are crucial to ensure the quality of the finished product, especially in the case of non-pasteurized beer.
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Development of instrumental and sensory analytical methods of food obtained by traditional and emerging technologiesComandini, 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.
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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.
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Physico-chemical and microstructural properties of food dispersionsGlicerina, 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.
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Sensory and instrumental profiling of apples: a new tool for quality assessmentCorollaro, 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.
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Milk and dairy products: evaluation of bioactive components by analytical techniquesGuerra, 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.
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Patterning soft matter for cell culturingTortorella, Silvia <1985> 08 April 2015 (has links)
In the search to understand the interaction between cells and their underlying substrates, life sciences are beginning to incorporate micro and nano-technology based tools to probe, measure and improve cellular behavior. In this frame, patterned surfaces provide a platform for highly defined cellular interactions and, in perspective, they offer unique advantages for artificial implants. For these reasons, functionalized materials have recently become a central topic in tissue engineering.
Nanotechnology, with its rich toolbox of techniques, can be the leading actor in the materials patterning field. Laser assisted methods, conventional and un-conventional lithography and other patterning techniques, allow the fabrication of functional supports with tunable properties, either physically, or topographically and chemically. Among them, soft lithography provides an effective (and low cost) strategy for manufacturing micro and nanostructures.
The main focus of this work is the use of different fabrication approaches aiming at a precise control of cell behavior, adhesion, proliferation and differentiation, through chemically and spatially designed surfaces.
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Interfacial interactions, charge transport and growth phenomena in Organic Field Effect TransistorsKyndiah, Adrica <1987> 08 April 2015 (has links)
Organic electronics is an emerging field with a vast number of applications having high potential for commercial success. Although an enormous progress has been made in this research area, many organic electronic applications such as organic opto-electronic devices, organic field effect transistors and organic bioelectronic devices still require further optimization to fulfill the requirements for successful commercialization. The main bottle neck that hinders large scale production of these devices is their performances and stability. The performance of the organic devices largely depends on the charge transport processes occurring at the interfaces of various material that it is composed of. As a result, the key ingredient needed for a successful improvement in the performance and stability of organic electronic devices is an in-depth knowledge of the interfacial interactions and the charge transport phenomena taking place at different interfaces. The aim of this thesis is to address the role of the various interfaces between different material in determining the charge transport properties of organic devices. In this framework, I chose an Organic Field Effect Transistor (OFET) as a model system to carry out this study as it An OFET offers various interfaces that can be investigated as it is made up of stacked layers of various material. In order to probe the intrinsic properties that governs the charge transport, we have to be able to carry out thorough investigation of the interactions taking place down at the accumulation layer thickness. However, since organic materials are highly instable in ambient conditions, it becomes quite impossible to investigate the intrinsic properties of the material without the influence of extrinsic factors like air, moisture and light. For this reason, I have employed a technique called the in situ real-time electrical characterization technique which enables electrical characterization of the OFET during the growth of the semiconductor.
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Synthesis and Characterization of New Aliphatic Biodegradable Polyesters for Packaging ApplicationsGenovese, Laura <1987> January 1900 (has links)
Until now, petrochemical-based plastics have been extensively used as packaging materials thanks to their low cost and excellent physic-mechanical properties. Unfortunately, as it is well-known, these materials are not readily degraded in the environments where they are disposed once their function has ended. As a consequence, thousands of tons of plastic packaging are disposed in landfills every year, causing a continuous pollution increment. In this view, replacing non-degradable plastics based on fossil oil with sustainable bio-based, biodegradable materials for short time applications is of great environmental importance.
Among biobased and biodegradable plastic packaging materials, one of the most economically competitive polymer class is represented by aliphatic polyesters, that have attracted considerable attention in last decades as they combine the afore mentioned features with interesting physical and chemical properties.
In this framework, the present research work focused on the modification of some interesting aliphatic polyesters, in order to prepare new materials, which guarantee full compostability and offer suitable characteristics, especially in terms of mechanical and barrier properties to be used in food packaging applications.
Simple, ecofriendly, cost-effective synthetic strategies have been employed to obtain the designed materials. All the synthesized polymers have been deeply characterized by the molecular, thermal and mechanical point of view. Moreover, their barrier properties have been studied to prove their suitability for packaging applications. Lastly, lab-scale composting experiments have been carried out, in order to check their potential compostability.
Solid-state properties and biodegradation rate can be tailored acting on chemical structure, copolymer composition and polymer architecture: in particular, the introduction of different amounts of ether- or thio-ether linkages or short ramifications along macromolecular backbone of parent homopolymer, or simply acting on soft/hard ratio in block structures permitted to modulate mechanical behaviour and biodegradation rate of the parent homopolymer itself, without compromising the good properties.
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