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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.
61

Formazione di biofilm e resistenza ai biocidi in Listeria / Biofilm formation and Biocide resistance in Listeria

MASSA, MARCO 24 February 2011 (has links)
La presente attività di ricerca ha avuto come oggetto di studio la formazione di biofilm in condizioni dinamiche: per raggiungere tale obiettivo, è stato costruito un idoneo apparato che permettesse di ottenere una valutazione quantitativa sia delle cellule presenti nella soluzione di crescita sia di quelle adese su tre materiali di prova(acciaio inossidabile, PET e rame). Oltre ad esprimere una valutazione dell’adesione batterica alle superfici, si è proceduto ad indagare sui possibili parametri sperimentali che potessero influenzare la formazione di biofilmdi Listeria su superfici abiotiche. Allo stesso tempo l’efficacia battericida di alcuni biocidi è stata valutata sulle cellule planctoniche così come su biofilm batterici sviluppati su superfici abiotiche. Il ruolo del sistema di quorum sensing basato su luxS nella formazione di biofilm batterici: un ceppo di L. innocua con buone capacità adesive è stato confrontato con il suo ceppo deficiente di luxS per la sua suscettibilità ad agenti biocidi così come per la sua capacità di adesione superficiale L’effetto della precendentemente menzionata inattivazione genetica sulla cinetica di crescita batterica e, quindi, sull’efficienza metabolica complessiva è stata esaminate mediante lo strumento BioscreenC. L’effetto inibitorio di due composti polifenolici è stato valutato sul ceppo deficiente di luxS così come sul ceppo originale. / The current research activity was focused on biofilm formation in dynamic conditions. A suitable device was thus constructed, in order to have a quantitative evaluation of the cells freely suspended in the flowing nutrient solution used as well as the sessile cells which adhered on the three tested surfaces (stainless steel, polyethylene therephthalate and copper). During this project, other than of a quantitative assessment of bacterial adhesion, we investigated also on the parameters which could affect significantly the biofilm formation of Listeria on abiotic surfaces. At the same time antimicrobial efficiency of selected biocides was investigated on planktonic cells as well as on bacterial biofilms grown on abiotic surfaces. The role of luxS-based quorum sensing system in the biofilm development process was evaluated: a luxS-null mutant of an adhesive strain of L. innocua was obtained through Campbell-like genetic inactivation and then evaluated for its sensitivity to biocidal agents and adhesion to surfaces, in comparison with its parental strains. Furthermore the effect of genetic inactivation on bacterial growth kinetic and thus on overall bacterial metabolic efficiency was assessed through the apparatus of BioscreenC. Finally two polyphenolic compounds were investigated for their inhibitory effect on Listeria.
62

Estudis biosistemàtics en les espècies ibèrico-baleàriques de les seccions "Artemisia" i "Seriphidium" Besser del gènere "Artemisia" L.

Vallès Xirau, Joan, 1959- 01 September 1986 (has links)
El genere "Artemisia" L., pertanyent a la família "Asteraceae" Dumortier o "Compositae" Giseke, subfamilia "Asteroideae", tribu "Anthemideae" Cass., subtribu "Chrysanthemineae" Less., és constituït per un nombre d'espècies proper a 300, variable segons els autors, àmpliament repartides per l'hemisferi nord, sobretot a Europa, Àsia, Africà del Nord i Amèrica del Nord i Central, bé que algunes són presents a l'hemisferi sud, per exemple a Xile i en alguns punts del sud del continent africà.Els principals tractadistes acorden al gènere origen eurasiàtic a causa de la major riquesa i diversificació d'espècies existent en aquesta zona. Concretament, el centre primari de diferenciació podria ser l'Àsia central soviètica. KRASHENINNIKOV (1946) estableix 6 centres eurasiàtics d'especiació per al gènere: xino-nipó, angaria, beringià, asiàtic central, asiàtic mitjà i europeo-mediterrani.Es lògic de suposar que les espècies del gènere atenyeren el continent americà des d'Àsia a través de l'estret de Bering; "A. frígida" Willd. i "A. dracunculus" L. es troben naturalment en les dues àrees i foren, doncs, probablement, l'origen de l'expansió americana del grup (MCARTHUR, 1979). Tot amb tot, BEETLE (1979) postula per al gènere origen nord-americà. En el conjunt de la conca mediterrània, el nombre d'espècies d' "Artemisia" decreix de nord a sud i d'oest a est (OUYAHYA, 1980).A la Península Ibèrica, situada a l'extrem oest d'aquesta conca, troben llur límit meridional o occidental alguns taxons (els grups d' "A. chamaemelifolia" i "A. caerulescens",posem per cas) i llur límit nord d'altres (els d'afinitat ibero-nor.d'africana, com el grup d'A. "herba-alba"). I s'hi mantenen interessants endemismes com "A. barrelieri", "A. hispànica" i "A. granatensis".Diverses espècies del gènere tenen aplicació com a estabilitzadores de sòls (MCARTHUR, 1979) i com a fre a processos de desertització (LE HOUËROU, 1979). D'altra banda, tenen gran significació en agroecosistemes des del punt de vista pastoral, sobretot a Amèrica del Nord. (MCARTHUR., 1979) i a l'Africà del Nord (OUYAHYA, 1980). Són d'interès en la fabricació de diversos licors (vermut, absenta) i com a espècies condimentarles (estragó).En el camp medicinal, en podem destacar dos aspectes: per una part, algunes espècies són productores d'al.lèrgies i d'altres generen diverses intoxicacions; i d'altra banda, moltes d'elles tenen compostos amb poderoses accions farmacològiques. Entre aquestes darreres, esmentem la clàssica droga vermífuga coneguda com a santònic, "semen contra" o "semen contra vermes", constituïda pels capítols d' "A. cina" Berg., "A. santonicum" L. i altres espècies orientals relacionades, els principis actius de la qual són lactones sesquiterpèniques. En terres ibèriques, "A. herba-alba" és emprada popularment amb les mateixes finalitats antihelmíntiques.Des del punt de vista d'aplicació i pensant en el nostre àmbit geogràfic, els tres aspectes esmentats tenen interès, tal com es desprèn dels usos populars de les plantes: Diverses espècies, sobretot "A. vulgaris" i "A. absinthium," són utilitzades en l'elaboració de begudes espirituoses. D'altres, bàsicament "A. herba-alba", dominen vastes extensions de territori i són consumides per bestiar divers; podrien ser, doncs, racionalment destinades a pastures.I, finalment, algunes tenen virtuts medicinals. Són, principalment, "A. herba-alba", "A. caerulescens", "A. barrelieri", "A. hispànica", "A. absinthium", "A. arborescens" i "A. granatensis". Material ibèric d'algunes d'aquestes entitats ha estat objecte d'estudis fitoquímics (GONZALEZ & al, 1974; VILLAR & al., 1983) que poden ser la base per a una explotació d'algunes d'elles amb finalitats farmacològiques.L'interès pastoral, alimentari i terapèutic, la situació de la Península Ibèrica i les Illes Balears amb alguns grups crítics o conflictius i el fet que, en el nostre àmbit geogràfic, la darrera monografia del gènere datés dels temps de Moritz Willkomm (1821-1895) ens han menat a intentar dur a terme la revisió de les "Artemisia" ibèricobaleàriques, que comencem per les seccions "Artemisia" i "Seriphidium", des del punt de vista biosistemàtic, sense negligir els mètodes i els criteris de la taxonomia clàssica, però incorporant, a més, noves tècniques que permetin una visió més fina i aprofundida dels problemes.No volem creure que amb el nostre treball hagi quedat completament resolta tota la casuística que afecta els grups estudiats; esperem, això sí, que el que hem fet pugui constituir una aportació sòlida i actualitzada per a continuar avançant en la recerca sobre aquest interessant grup de plantes.
63

OMICS APPROACH TO INVESTIGATE THE ROLE OF ENTERIC BACTERIA IN METABOLIZING FOOD COMPONENTS

SENIZZA, ALICE 08 April 2020 (has links)
In questa tesi di Dottorato, l’obiettivo era valutare l’impatto di diversi ingredienti alimentari sul metabolismo di alcuni batteri intestinali e viceversa, mediante l’applicazione di tecniche omiche. Utilizzando le tecniche di metabolomica e trascrittomica, è stata studiata la risposta all’acido linoleico del ceppo Bifidobacterium breve DSM 20213. Utilizzando un approccio combinato di metagenomica e metabolomica, è stato possibile studiare le modifiche a carico del microbiota intestinale, del profilo fenolico e degli acidi grassi, in biscotti senza glutine (a base di erba medica) durante digestione e fermentazione in vitro. Inoltre, è stato valutato come alcuni batteri potessero interferire negativamente su una terapia farmacologica a base di Diclofenac, un farmaco usato per alcune patologie intestinali. Per questo tipo di studio è stata utilizzata la spettrometria di massa ad alta risoluzione, che ha consentito di ipotizzare un coinvolgimento dell’enzima batterico β-glucuronidasi. Una sola tecnica omica, seppure di ultima generazione, non permette di valutare tutte le modificazioni del microbiota intestinale data la complessità dei fattori coinvolti. Per questa ragione, integrare più approcci omici potrebbe risultare una buona strategia per analizzare il reale impatto del microbiota sulla salute dell’ospite. Questo permetterebbe di valutare le interazioni microbiota-ospite, i principali metabolismi e le interconnessioni tra gruppi batterici coinvolti nella risposta ad uno stimolo esterno come l’assunzione di particolari ingredienti con l’alimentazione. / The aim of the present PhD thesis was to explore the metabolic response of intestinal bacteria to food components by using ‘omics’ approaches. In particular, the first part of this thesis was focused on the effect of linoleic acid on Bifidobacterium breve DSM 20213 strain. Firstly, an untargeted metabolomics-based approach was used to explore the primary changes in metabolic profile of this strain grown in presence of linoleic acid. Secondly, the gene expression of B. breve DSM 20213 induced by linoleic acid exposure was investigated. Integrated use of metabolomics/transcriptomics was applied to better understand the response mechanisms to linoleic acid stress. In the third part of the thesis, using a combination of metagenomics and metabolomics, the in vitro large intestine fermentation of gluten-free rice cookies containing alfalfa seed was investigated. In the last part of my PhD, the negative effect of β-glucuronidase producing bacteria was evaluated by means of qualitative high-resolution mass spectrometry. Based on my experience there is not a gold standard approach for evaluating a complex environment such as the gastrointestinal tract. For this reason, an integrated use of different techniques should be mandatory to have an accurate framework of gut microbiota composition, its potential metabolic network and the impact on the host physiology and health.
64

Understanding the role of human microbiota on sensory perception

Menghi, Leonardo 06 June 2023 (has links)
While consumer awareness of benefits of adequate nutrition has noticeably surged in recent years, developing countermeasures against improper eating habits still represents a public health priority in view of the growing prevalence of diet-related diseases. Eating behaviours are complex phenomena driven by a spectrum of biological and environmental factors, wherein (chemo)sensory perception is reckoned amongst the most influential. Analogously, chemosensation is affected by a myriad of determinants, and this warrants the commonly observed large variation in how tastes and smells are perceived among individuals. Given how such variability intimately relates to dietary habits, deciphering its underlying mechanisms is paramount to promoting healthier food choices. In this vein, emerging evidence suggests that human eating behaviours can also be affected by interactions between the gastrointestinal microbiota and the chemosensory systems. Despite growing interest, the sensory-oriented microbiome field suffers from obvious limitations due to its recent emergence. As a result, little efforts has been devoted to elucidating: a) the associations between the oral microbiota and olfaction or known psychological mediators of sensory perception; b) the links between the distal gut microbiota and taste functioning; c) the consequences of interactions between chemosensation and the gastrointestinal microbiota on dietary intakes. Against this backdrop, this thesis aimed at expanding the current knowledge on the interplays between domains of sensory perception and the gastrointestinal microbiota and how these might mirror variations in habitual food habits. In detail, four studies probing the associations a) between a psychosocial correlate of sensory perception (food neophobia), olfaction (Chapter 2) and the oral microbiota (Chapter 3); and b) between distal gut (Chapter 4) or oral (Chapter 5) microbiota, taste functioning and dietary intakes are here presented. In Chapter 2 and 3, a healthy cohort of 83 individuals (57.8 % women; aged 22-68 yo) remotely filled out the common Food Neophobia Scale and the trait anxiety subscale of the State-Trait Anxiety Inventory prior to providing a salivary sample for subsequent metataxonomic analysis (16S rRNA gene sequencing). Next, volunteers were tested for orthonasal olfactory functioning via the Sniffin’ Sticks battery, and monitored for retronasal aroma release while consuming a strawberry jelly candy by nose-space analysis (Selected-Ion Flow-Tube Mass Spectrometry). In Chapter 4 and 5, instead, 100 young adult volunteers (52 % women; aged 18-30 yo) attended a 7-day lasting remote protocol where responsiveness to genetically-mediated bitterness of 6-n-propylithiuracil (PROP), hedonics and intensity of oral sensations elicited by ten commercially-available food products, a battery of food-related psychological traits, a 4-day food record, and one salivary and one stool sample (sequenced by targeting the 16s rRNA gene) were collected. Overall, results substantially strengthen past evidence suggesting: a) that pronounced neophobic tendencies translate into higher levels of (negative) emotional activation or arousal towards foods; b) the existence of homogenous groups of individuals with generalized hypergeusia towards oral stimulations; c) that hyperresponsiveness to a peculiar taste quality is a barrier to the intake of foods evoking such sensation; d) that habitual consumption of dietary fibers and simple carbohydrates can shape both the gut and oral microbial ecology, respectively. Intriguingly, food neophobia and poor olfaction were positively associated with oral microbial markers of dysbiosis (e.g., Porphyromonas gingivalis), whilst a Clostridia-enriched salivary microbiota co-occurred with low responsiveness to alarming oral sensations (astringency, bitter, sour) elicited by real foods. Similarly, an ample panel of commensal gut bacterial genera mainly allocated to the families Lachnospiraceae and Ruminococcaceae was found to be enriched in individuals exhibiting lower acuity to both tastes (bitter, salty, sour, sweet) and trigeminal sensations (astringent, pungent). Besides taxonomically annotating a range of microbial taxa tied to sensory perception, putative metabolic pathways used by salivary and gut microbial communities to modulate taste perception were inferred and discussed. To conclude, this thesis supports the notion that the gastrointestinal microbiota is an additional candidate to explain interindividual variations in taste and smell perception, and provides novel important insights into the aetiology of eating behaviours. More importantly, this work also offers methodological cues to robustly assess the associations between chemosensation and host-related non genetic factors, and paves the way for future interventional studies targeting the efficacy of sensory-related microbial taxa as potential modulators of dietary habits.
65

Approccio integrato alla selezione di nuovi probiotici per l'applicazione nell'uomo / INTEGRATED APPROACH TO THE SELECTION OF NEW PROBIOTICS FOR HUMAN APPLICATION

GUIDESI, ELENA 17 March 2016 (has links)
Durante la mia tesi di dottorato ho selezionato nuovi potenziali ceppi probiotici, combinando l'approccio convenzionale con l’utilizzo di piattaforme di nuova concezione. Mi sono concentrata inizialmente sul cosiddetto "screening tradizionale" finalizzato all'isolamento di nuovi ceppi batterici di lattobacilli e bifidobatteri e alla valutazione della loro sicurezza per il consumo umano e della loro efficacia. I ceppi selezionati sono stati quindi sottoposti ad uno screening più specifico, a seconda dell'applicazione a cui sarebbero stati destinati. In questa fase sono stati utilizzati sia test in vitro che modelli animali, al fine di valutare l'applicabilità dei ceppi di recente selezionati come probiotici per la promozione della salute umana e il loro possibile impiego in campo alimentare. Ho valutato il potenziale utilizzo dei ceppi nell’integrazione alimentare di soggetti che seguono diete ad alto contenuto proteico per ridurre il rischio di accumulo intestinale di ammine biogene, e ho individuato un ceppo di Lactobacillus con presunta attività ammino-degradativa. L'obiettivo principale di un’altra attività di screening è stato lo studio degli effetti immunomodulanti di nuovi ceppi: combinazioni di probiotici sono risultati buoni candidati per il trattamento delle malattie infiammatorie e autoimmuni (miastenia grave e sclerosi multipla) nel modello di topo. Infine, i ceppi sono stati sottoposti a screening per una potenziale applicazione in campo alimentare, finalizzata ad indagare la possibilità di produrre formulazioni di probiotici “atomizzati” da utilizzare insieme alla base commerciale del gelato. / During my PhD thesis I screened new potential probiotic strains by combining conventional approach to newly designed platforms. I focused first on the so-called "conventional screening” aimed to the isolation of new bacterial strains of lactobacilli and bifidobacteria and to assess their safety for human consumption and their efficacy by in-vitro methods. Selected strains were then submitted to a targeted screening by specifically designed models, depending on the application to which they would be destined. These models combined in vitro tests and animal models in order to assess the applicability of newly selected strains as probiotics for the promotion of human health and their possible use in food field. I evaluated the potential use of strains in the food supplementation of subjects that follow high-protein diets to reduce the risk of intestinal accumulation of biogenic amines, and I identified a strain of Lactobacillus with alleged amino degradative activity. The main objective of another screening activity was the study of the immunoregulatory effects of new strains: combinations of probiotics resulted good promising candidates for the treatment of inflammatory and autoimmune diseases (myasthenia gravis and multiple sclerosis) in rat model. Finally, strains were screened for a potential application in food field, in order to investigate the possibility of producing spray-dried probiotic formulations to be used together with commercial ice-cream bases.
66

Sviluppo di processo di tecnologie alimentari per Paesi in via di sviluppo Produzione di Aceto da Scarti di Ananas / PROCESS DEVELOPMENT OF FOOD TECHNOLOGIES FOR INCOMING COUNTRIES VINEGAR PRODUCTION FROM PINEAPPLE WASTE

RODA, ARIANNA 17 March 2016 (has links)
L’utilizzo degli scarti da parte dell’industria alimentare costituisce una sfida importante per ridurre le perdite di cibo, aumentare la sostenibilità della produzione alimentare e, pertanto, incrementare la sicurezza alimentare specialmente nei paesi in via di sviluppo. Obiettivo della presente tesi è ottenere aceto dagli scarti dell’ananas tramite idrolisi enzimatica preceduta da pre-trattamento fisico, fermentazione alcolica con differenti ceppi di Saccharomyces cerevisiae, addizionati di Lactobacillus delbruekii o Lactobacillus plantarum del liquido saccarificato, e fermentazione acetica con Acetobacter aceti in un impianto pilota. I campioni ottenuti dalle prove di saccarificazione, fermentazione alcolica e acetica sono stati analizzati per pH, acidità totale, grado Brix, zuccheri, acidi organici, etanolo e per i composti volatili. Una caratterizzazione dettagliata dell’aceto è stata eseguita tramite UPLC/Q-TOF e GC-MS. / Using waste from the food industry is a major challenge to reduce food losses, to increase the sustainability of food production and, therefore, increase food security, especially in developing countries. The objective of this thesis is to get vinegar from pineapple waste by means of: enzymatic hydrolysis proceeded by physical pre-treatment; alcoholic fermentation of the saccharified juice with different strains of Saccharomyces cerevisiae and Lactobacillus delbruekii or Lactobacillus plantarum; acetic fermentation with Acetobacter aceti in a pilot plant. Samples obtained from saccharification, alcoholic and acetic fermentation were analyzed for pH, total acidity, total soluble solid (TSS), sugars, acids, ethanol, and volatile compounds. A detailed characterization of vinegar was carried out through UPLC/Q-TOF and GC-MS.
67

ESTRATTI AD ELEVATO CONTENUTO DI ANTIOSSIDANTI OTTENUTI DA RESIDUI DELLA VINIFICAZIONE: ESTRAZIONE CON SOLVENTE e MIGLIORAMENTO DEL PROCESSO DI ESTRAZIONE ATTRAVERSO L'APPLICAZIONE DI TENSIOATTIVI / ANTIOXIDANT EXTRACTS FROM WASTE GRAPE SKINS: CONVENTIONAL SOLVENT EXTRACTION AND SURFACTANT APPLICATION FOR PROCESS INTENSIFICATION

BOSI, MATTEO 28 January 2015 (has links)
La tesi di dottorato è stata sviluppata all'interno del progetto nazionale Valorvitis ed è suddivisa in due parti. La prima riguarda la caratterizzazione chimica di sei estratti di vinacce d’uva ottenute diverse varietà di uva: tre a bacca rossa( Pinot Noir, Barbera e Nebbiolo) e tre a bacca bianca (Moscato, Muller Thurgau e Chardonnay). Ogni estratto è stato caratterizzato per contenuto e composizione in composti fenolici. La seconda attività consiste nello studio di un metodo alternativo di estrazione-purificazione basato sull'impiego di Gas Aphron Colloidali (CGAs) con la finalità di ridurre i costi di processo, la quantità di solvente da utilizzare durante la fase di estrazione e, allo stesso tempo, aumentare il grado di purezza dell’estratto in termini di contenuto polifenolico. / The present PhD thesis work was carried out under the framework of the Valorvitis.Extracts have been obtained from different red (Pinot Noir, Barbera and Nebbiolo) and white (Moscato, Muller Thurgau and Chardonnay) grape marcs and quantitatively analysed for the content of total phenolics, tannins, anthocyanins, cinnamic acids, flavonoids, flavonols, sugars (glucose and fructose) and for the anti-oxidant power (AOP). A new extraction-purification process based on CGAs application has been investigated. CGAs were first reported by Sebba (1987) as micro bubbles, with dimension among 10–100 μm, composed of a gaseous inner core surrounded by a thin surfactant film, which are created by intense stirring of a surfactant solution above its critical micellar concentration. Surfactants are able to catch phenolics thanks to both electrostatic and hydrophobic interactions depending on the surfactant (ionic or non-ionic) and on the phenolic compound. In this project the low-cost non-ionic food grade surfactant Tween 20 was used.
68

Penicilli e Aspergilli associati al formaggio grana Approccio multifasico all'identificazione, fabbisogni ecologici e produzione di tossine / PENICILLIA AND ASPERGILLI ASSOCIATED TO GRANA CHEESE MULTIPHASIC IDENTIFICATION APPROACH, ECOLOGICAL NEEDS AND TOXINS PRODUCTION

DECONTARDI, SIMONE 31 May 2017 (has links)
Recentemente, l’ocratossina A (OTA) è stata segnalata in formaggio grattugiato confezionato: si ritiene sia stata prodotta dallo sviluppo di alcuni funghi durante il periodo di maturazione. Gli studi presentati in questa tesi hanno avuto lo scopo di migliorare la conoscenza dei funghi, Aspergilli e Penicilli, associati al formaggio di tipo grana. Si è dunque provveduto alla loro identificazione tramite approccio multifasico, eseguendo anche prove ecologiche per definire i fabbisogni delle specie presumibilmente dominanti. Obiettivo finale sarà quello di predire il rischio di contaminazione da micotossine alle condizioni ambientali di stagionatura del prodotto. Aspergillus puulaauensis e alcune specie del genere Penicillium (P.crustosum and P. solitum) sono state rilevate con maggior frequenza, mentre non sono state rilevate nei campioni di crosta le specie P. nordicum e P. verrucosum. In ogni caso, le condizioni ambientali dei locali di maturazione (15-22°C; 72-88% UR) sono risultate favorevoli allo sviluppo di queste ultime, dando adito a preoccupazione circa una possibile contaminazione da OTA; tuttavia, il ruolo di altre specie micotossigene, ad esempio P. crustosum, non va sottovalutato. Le azioni di contrasto verso questi funghi micotossigeni dovrebbero, innanzitutto, ridurre l’inoculo presente nell’aria: l’ozono sembra efficace in tal senso; inoltre, l’utilizzo della luce blu potrebbe ridurre notevolmente la crescita fungina sulla superficie dei formaggi e delle scaffalature. Le informazioni fornite in questa tesi saranno utili ai produttori e agli altri operatori della filiera di questo prodotto, aiutandoli ad attuare una miglior gestione del rischio e a garantire un prodotto sicuro e di elevata qualità ai consumatori. / Ochratoxin A (OTA) was detected a few years ago in Italian packed grated cheese, and supposed to be produced by fungal growth during cheese ripening. The works managed and presented in this thesis aimed to improve knowledge about mycotoxigenic Aspergilli and Penicillia associated to Italian grana cheese. A multiphasic approach was applied for their identification and ecological trials were organised to define fungal needs of the expected dominant species. The objective was to predict the risk of mycotoxin contamination during the ripening condition of grana cheese. Aspergillus puulaauensis and some Penicillium spp (P.crustosum and P. solitum) were the prevalent species associated to grana cheese, while neither P. nordicum, nor P. verrucosum were detected in cheese rind. However, the environmental conditions of the ripening rooms (15-22°C; 72-88% RH) are favourable to P. nordicum and P. verrucosum, reinforcing concern about possible OTA contamination, but other mycotoxigenic species such as P. crustosum must not be neglected. Actions against those mycotoxigenic fungi should mainly reduce total inoculum in the environmental air: ozone is reported to be effective in this sense; moreover, blue light may significantly reduce fungal growth on cheese and shelves surfaces. Information provided therein will be useful for producers and stakeholders to perform a better risk management and guarantee a safe, high-quality product to consumers.
69

THE ROLE OF DIETARY STARCH AND NON-STARCH POLYSACCHARIDE IN SWINE PERFORMANCE AND NUTRIENT RECEPTORS GENE EXPRESSION

RZEPUS, MARCIN MATEUSZ 28 January 2015 (has links)
The present work has been divided into two parts. At first, research projects attempt to evaluate technologies that increase digestibility of energy and other nutrients in cereal grains and their co-products. Differences in starch digestibility have been attributed to various factors, including the the type of corn endosperm, the presence of proteins and prolamins, the presence of lipids, the amylose-amylopectin ratio, the starch granule structure, the particle size, the conservation and processing methods. Second part of my work was dedicated to investigate the sensors of diet compounds which could be considered as potential markers to monitor nutrition status of organism. Activation of these receptors is believed to influence the hunger-satiety cycle, and their expression levels may be altered by dietary composition. Thus, the aim was to investigate for the first time the effect of arabinoxylans (AX) and β-glucans (BG) on the relative level of expression of carbohydrates, amino and fatty acid nutrient sensors genes in porcine oral and non-oral tissues. / The present work has been divided into two parts. At first, research projects attempt to evaluate technologies that increase digestibility of energy and other nutrients in cereal grains and their co-products. Differences in starch digestibility have been attributed to various factors, including the the type of corn endosperm, the presence of proteins and prolamins, the presence of lipids, the amylose-amylopectin ratio, the starch granule structure, the particle size, the conservation and processing methods. Second part of my work was dedicated to investigate the sensors of diet compounds which could be considered as potential markers to monitor nutrition status of organism. Activation of these receptors is believed to influence the hunger-satiety cycle, and their expression levels may be altered by dietary composition. Thus, the aim was to investigate for the first time the effect of arabinoxylans (AX) and β-glucans (BG) on the relative level of expression of carbohydrates, amino and fatty acid nutrient sensors genes in porcine oral and non-oral tissues.
70

GLUTEN - FREE FOOD SYSTEM: SCREENING OF POLYPHENOLS AND THEIR BIO ACCESSIBILITY THROUGH IN VITRO GASTROINTESTINAL PROCESSES AND METABOLOMICS - BASED STUDIES

ROCCHETTI, GABRIELE 03 April 2019 (has links)
Circa l’1% della popolazione mondiale è colpita da celiachia. I celiaci sono costretti a seguire una dieta priva di glutine e molto spesso quest’ultima risulta essere sbilanciata e/o carente in molti nutrienti. Recentemente, l’uso di matrici alternative al frumento, come pseudocereali, legumi e cultivar di riso pigmentate sta riscuotendo grande interesse a causa del loro elevato quantitativo di composti bioattivi (polifenoli). Quindi, considerando l’importanza attuale dei polifenoli sia nella formulazione tecnologica che nella promozione di aspetti salutistici degli alimenti senza glutine, lo scopo di questa tesi è stata basata su: 1) profilazione dei polifenoli in matrici prive di glutine (farine non di frumento, legumi, pseudocereali e frutta secca) e loro proprietà antiossidanti in vitro; 2) valutazione dell’impatto di trattamenti termici e di fermentazioni microbiche sul profilo fenolico di queste matrici prive di glutine; 3) valutazione del ruolo dei polifenoli come inibitori degli enzimi amilolitici; e 4) valutazione del destino dei polifenoli caratterizzanti alimenti senza glutine durante processi in vitro simulanti digestione gastrointestinale e fermentazione fecale. I polifenoli sono stati analizzati sfruttando tecniche di metabolomica mirata/non-mirata. / Around 1% of world population is affected by coeliac disease. Coeliac people are constrained to follow a strict gluten free (GF) diet and very often this latter is unbalanced and lacks in many nutrients. In the last years, the exploitation of alternative crops or underutilized species, such as pseudocereals, legumes and pigmented cereal cultivars, is gaining interest because of their amount and profile of bioactive compounds, such as polyphenols. Therefore, considering the actual importance of polyphenols for both the formulation of GF foods and their health-promoting properties, the current PhD thesis was based on: 1) the profiling of polyphenols in GF raw materials (such as non-wheat flours, legumes, pseudocereals and nuts) and their in vitro antioxidant activities; 2) the evaluation of the impact of different heat treatments and microbial fermentations on the phenolic profile of GF raw materials; 3) the investigation of polyphenols in GF foods as inhibitors of digestive enzymes; and 4) the assessment of the fate of polyphenols characterizing GF foods during simulated in vitro gastrointestinal and fermentation processes. Polyphenols were analysed by means of targeted/untargeted metabolomics-based approaches (i.e., high resolution chromatography and mass spectrometry platforms).

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