• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 12
  • 12
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 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.
1

Ageing of starch and starch-sugar systems in the glassy state

Martinet, Cecile January 2001 (has links)
No description available.
2

Démarche intégrée pour l’identification de mécanismes et d'opérations unitaires déterminants de la qualité du gari / Integrated approach for the identification of mechanisms and unit operations determining the quality of gari

Escobar Salamanca, Andrés Felipe 30 November 2018 (has links)
Le procédé de transformation des racines de manioc en gari reste la plupart du temps artisanal et dépendant du savoir-faire des opératrices. Étant constitué d’une suite d’opérations unitaires (râpage, fermentation/pressage, tamisage et cuisson), il est nécessaire de déterminer les opérations-clefs déterminantes de la qualité du produit. Ainsi, dans ce travail, le procédé a été analysé dans sa continuité au travers du suivi de réponses biochimiques, granulométriques et hydro-texturales du produit durant sa transformation. L’objectif du travail de thèse a été dans un premier temps de développer des outils et méthodes permettant le suivi des états physiques et biochimiques du produit tout au long de sa transformation à l’échelle laboratoire. Cette démarche a permis de dégager certains mécanismes contribuant à la transformation du produit. Il a été mis en évidence le drainage d’une partie du liquide intra-cellulaire lors du pressage ainsi que deux mécanismes d’agglomérations successifs lors de l’élaboration du gari. Les résultats et les mécanismes déduits des observations réalisées à l’échelle laboratoire ont par la suite été confrontés à ceux obtenus sur le terrain (Bénin) dans des conditions moins maîtrisées et sous l’effet d’un changement d’échelle. L’opération de cuisson, à la fois très contraignante et ressortant comme une opération unitaire clef a été, par la suite, plus particulièrement étudiée. Pour cela, le comportement (choix et gestes) de deux opératrices a été enregistré de façon à mettre en évidence le rôle de l’opératrice lors de la cuisson. L’ensemble des résultats montrent que la qualité des garis repose en grande partie sur le savoir faire de l’opératrice. Il ressort cependant que les critères de qualité du gari qui guide l’opératrice lors de la cuisson et la conduisent à ajuster son comportement sont, bien sûr, ceux qui lui sont accessibles (couleur, taille, …), mais ne sont pas suffisants pour atteindre teneurs en composés cyanogénique résiduels recommandées par le Codex Alimentarius de la FAO. / The cassava process of converting cassava roots into gari remains mostly artisanal and depends on the know-how of the operators. As it consists of a series of unit operations (grating, fermentation/pressing, sieving and cooking), it is necessary to determine the key operations that determine the quality of the product. Thus, in this work, the process was analyzed in its continuity through the monitoring of biochemical, granule size and hydro-textural responses of the product during processing. The objective of the thesis work was initially to develop tools and methods to monitor the physical and biochemical states of the product throughout its processing on a laboratory scale. This approach has made it possible to identify some of the mechanisms that contribute to the elaboration of the product. It was found that part of the intracellular liquid drained during pressing and two successive agglomeration mechanisms were identified during the preparation of the gari. The results and mechanisms derived from laboratory scale observations were then compared with those obtained in the field (Benin) under less controlled conditions and scaling effect. The cooking operation, which is both very constraining and emerging as a key unitary operation, was then more particularly studied. For this purpose, the performance (choice and gestures) of two operators was recorded in order to highlight the role of the operator during the cooking process. All the results show that the gari quality is largely based on the operator's know-how. However, it appears that the product quality criteria that guide the operator during cooking lead her to adjust her practices are, of course, those that are accessible to her (colour, granule size, ...), but are not enough to reach the levels of residual cyanogenic compounds recommended by the FAO Codex Alimentarius.
3

Vliv výživy kapra obecného (Cyprinus carpio L.) na změnu kvality masa / The influence of carp nutrition (Cyprinus carpio) on changes of meat quality

JANOUŠEK, Petr January 2012 (has links)
The aim of this study was based on laboratory analysis of each parameter, an assessment of livestock interventions, current methods and techniques used in fishing enterprises. Experiments carried out on the market carp in ponds in the system Naděj and the hatcheries under the pond Svět where it was used mechanically and cooked cereals. After processing the fish fillets was done by measuring muscle textural profile. The highest average value of the hardness of the fish ponds was measured in control samples (25,008 ? 3,507 kg). Followed by samples of fish that were unprepared food whatsoever triticale (19,530 ? 2,842 kg). Fish feeding whole triticale heat-treated at 100 ° C (9,990 ? 1,506 kg) and heat-treated triticale mashed at 100 ° C (10,031 ? 1,696 kg) showed similar values of stiffness. The highest average value of the hardness of fish hatcheries was measured in samples of fish that were food whatsoever (20,420 ? 1,456 kg). In addition, followed in descending order of fish samples, which posed a triticale cooked at 100 ° C (11,198 ? 3,334 kg) of wheat at 100 ° C (10,286 ? 1,234 kg), barley at 100 ° C (8,564 ? 1,532 kg), and rye at 100 ° C (7,519 ? 1,993 kg).
4

Préparation d'alumine à porosité contrôlée : étude de l'interaction de la boehmite dans des solvants et des propriétés fonctionnelles des matériaux résultants. / Preparation of controlled porous alumina-based support : study of the boehmite interaction in solvants and the functional properties of the resulting materials

Morin, Camille 06 November 2014 (has links)
Les propriétés texturales des supports sont intimement liées à l’organisation des cristallites de boehmite (AlOOH, nH2O) lors des procédés de synthèse et mise en forme. La modification de cette organisation par dispersion de la boehmite dans des alcools a pour conséquence une exaltation de la porosité extrêmement intéressante pour les applications en catalyse sensibles aux limitations diffusionnelles. La mise en place d’une voie originale de préparation des supports par dispersion de boehmite dans un mélange de solvants protiques polaires a permis de mettre en évidence un contrôle de la porosité en fonction des ratios entre les solvants. La nature du solvant influe sur la cinétique d’agrégation et donc sur l’organisation des particules. La modulation de l’encombrement stérique et de l’affinité du solvant pour la surface de la boehmite permettent de contrôler l’épaisseur de la couche de solvatation formée à la surface. En conséquence de cette microstructure particulière en dispersion, les propriétés de l’alumine finale peuvent être ajustées sur une large gamme de porosité à surface spécifique constante. L’impact sur les autres propriétés fonctionnelles du matériaux, comme les propriétés mécaniques et catalytiques a été évalué. Une approche par la micromécanique à plusieurs échelles a été élaborée et conduit à des modules élastiques proches de ceux mesurés par microindentation. L’activité en hydrodémétallation est significativement améliorée avec l’élévation de la porosité, tout en gardant une activité en hydrodésulfuration élevée. Cette démarche est prometteuse pour la prédiction des propriétés du support final à partir du contrôle de la microstructure de la dispersion. / Textural properties of catalytic supports are closely related to the organization of boehmite crystallites (AlOOH, nH2O) during the synthesis and the shaping. The modification of this organization by mixing the boehmite with alcohols leads to an increase of the porosity which is very interesting for catalysis processes sensitive to diffusional limitations. A novel way of support preparation obtained by dispersing boehmite in mixed protic polar solvents allows highlighting a control of the porosity depending on the solvents ratio. The kinetic of aggregation, and hence the particles organization, is influenced by the solvent nature. The tuning of the steric effect and the affinity of the solvent for the boehmite surface allows controlling the solvation layer thickness. Consequently of this particular microstructure in dispersion, the porosity can be tuned on a wide range, while keeping a constant specific surface area. The impact on the functional properties of the support, like the mechanical and the catalytic properties, are estimated. A two-nested scales micromechanical approach was carried out and leads to elastic modulus close to the experimental one. Hydrodemetallization activity is greatly enhanced with the porosity, while preserving a high hydrodesulfurization activity. This study is promising in order to predict the properties of the final support from the control of the dispersion microstructure.
5

[en] INFLUENCE OF SYNTHESIS CONDITIONS ON PHYSICOCHEMICAL PROPERTIES OF SNO2 / [pt] INFLUÊNCIA DOS PARÂMETROS DE SÍNTESE SOBRE PROPRIEDADES FÍSICO-QUÍMICAS DE SNO2

RENATO MOUTINHO DA ROCHA 27 October 2005 (has links)
[pt] Resultados de testes preliminares para a reação de obtenção de formaldeído a partir de metóxi metano (DME) utilizando um catalisador Mo/SnO2 indicaram a necessidade de sistemas altamente ativos. Considerando-se que espécies dispersas de Mo parecem ser as mais efetivas para essa reação, e que a obtenção dessas espécies deve ser favorecida com o uso de um suporte de elevada área específica, estudou-se, neste trabalho, a influência dos parâmetros de síntese nas propriedades fisico-químicas do SnO2 preparado a partir de três diferentes métodos: a partir do ataque de Sn0 com HNO3, a partir da reação entre Sn+4 e NH4OH, e a partir da reação entre Sn+4 e dodecilamina. Foram realizadas alterações na forma de mistura das soluções, no tempo e na temperatura de reação, e na razão de aquecimento durante a calcinação. As amostras obtidas foram caracterizadas por adsorção de N2 para medições de área específica e distribuição de tamanho de poros, difração de raios-X e espectroscopia de reflectância difusa na região do UV-visível. Os resultados mostraram que todas as amostras obtidas são mesoporosas, embora apresentem diferentes valores de área específica, de tamanho de cristal, e de diferença de energia entre os orbitais HOMO-LUMO. Dentre os métodos estudados, o que partiu da reação entre Sn+4 e NH4OH apresentou maior sensibilidade às alterações realizadas, e as amostras assim obtidas apresentaram maiores valores de área específica; por outro lado, as amostras obtidas a partir do ataque de Sn0 com HNO3 não apresentaram variações texturais e estruturais significativas. Os resultados indicam ainda que, dentre os parâmetros alterados, a temperatura e o tempo da reação parecem ser os mais importantes. / [en] Preliminary tests on the reaction for formaldehyde production from metoxi methane (DME) using a Mo/SnO2 catalyst have indicated the necessity of highly active systems. Dispersed species of Mo seem to be the most effective for this reaction which may be favored by the use of a support of high specific area. Therefore the influence of the synthesis parameters on the physicochemical properties of the SnO2 has been studied in this work. This oxide has been prepared by three different methods: by the oxidation of Sn0 using HNO3, by the reaction of Sn+4 with NH4OH, and by the reaction of Sn+4 with dodecylamine. Variations on the way of mixing the solutions, on the time and the temperature of the reaction, and on the heating rate of the calcinations step have been carried out. These samples have been characterized by N2 adsorption for measurements of specific area and pore size distributions, X-ray diffraction and UV-visible diffuse reflectance spectroscopy. The results have shown that all samples are mesoporous even though they have exhibited distinct values of specific area, crystal size and HOMO-LUMO gap energy. The reaction of Sn+4 with NH4OH has presented the greatest sensitivity to the synthesis parameters, and it has provided samples with the highest specific area values. However the samples prepared by the oxidation of Sn0 using HNO3 have not been influenced. The results have also indicated that the temperature and the reaction time seem to be the most important parameters.
6

Možnosti ovlivnění textury masa kapra obecného (Cyprinus carpio) / Possibilities affection the texture of meat common carp (Cyprinus carpio)

SUCHÁNEK, David January 2009 (has links)
Texture was measured on texture analyzer TA.XT plus the manufacturer's Stable Micro System, using the methods of texture profile analysis (TPA) in the general carp fillets (Cyprinus carpio). Were measured basic textural properties such as hardness, chewiness, springiness and cohesiveness. Course of change of these textural characteristics were monitored during the freezing and marinating. In both cases, the differences statistically substantiating some textural properties.
7

Senzorski, nutritivni i funkcionalni profil integralne testenine sa dodatkom heljdinog brašna / Sensory, nutritional and functional profile of whole grain pasta with buckwheat flour addition

Škrobot Dubravka 06 June 2016 (has links)
<p>U okviru disertacije ispitani su i upoređeni pokazatelji kvaliteta integralnog p&scaron;eničnog i integralnog heljdinog bra&scaron;na dobijenog mlevenjem netretiranih (netretirano integralno heljdino bra&scaron;no) i autoklaviranih zrna heljde (autoklavirano integralno heljdino bra&scaron;no). Nakon ispitivanja nutritivnih i funkcionalnih svojstava pomenutih bra&scaron;na, kreirane su i proizvedene integralne taljatele sa različitim sadržajem integralnog heljdinog bra&scaron;na (10&ndash;30%).<br />Pokazatelji senzorskog, nutritivnog i funkcionalnog kvaliteta proizvedenih taljatela sa integralnim heljdinim bra&scaron;nima ispitani su u poređenju sa kontrolnim uzorkom taljatela od integralnog p&scaron;eničnog bra&scaron;na.<br />U ispitivanim uzorcima bra&scaron;na i taljatela određeni su osnovni hemijski sastav, sadržaj mineralnih materija, sadržaj ukupnih rastvorljivih polifenola, utvrđen je kvalitativni i kvantitativni sastav polifenolnih jedinjenja, ispitana je antiradikalska aktivnost na DPPH˙ i određen je sadržaj fitinske kiseline i 5-hidroksimetilfurfural.<br />Pored analize nutritivnih i funkcionalnih svojstava, na taljatelama su sprovedena ispitivanja fizičkih osobina (dimenzije) i svojstva taljatela pri kuvanju. Instrumentalno su izmereni boja i teksturna svojstva nekuvanih i kuvanih taljatela. Senzorska ocena taljatela sprovedena je uz primenu panela utreniranih ocenjivača, metodom bodovanja i panela potro&scaron;ača, testom dopadljivosti.<br />Dobijeni rezultati ukazuju da se supstitucijom dela integralnog p&scaron;eničnog bra&scaron;na integralnim heljdinim bra&scaron;nom (autoklaviranim ili netretiranim) postiže unapređenje nutritivnog i funkcionalnog profila uzoraka obogaćenih taljatela, uz manje ili vi&scaron;e izraženo naru&scaron;avanje senzorskog profila, u zavisnosti od stepena supstitucije i vrste integralnog heljdinog bra&scaron;na.</p> / <p>This study investigated quality parameters of wholegrain wheat flour and wholegrain buckwheat flour from non-treated buckwheat grains (non-treated wholegrain buckwheat flour) and autoclaved buckwheat grains (autoclaved wholegrain buckwheat flour). After investigation of nutritional and functional properties of aforementioned flours, new wholegrain tagliatelle formulations, with different wholegrain buckwheat flour content (10&ndash;30%) have been developed.<br />Sensory, nutritional and functional quality parameters of buckwheat containing tagliatelle samples were analysed and compared with control tagliatelle sample from wholegrain wheat flour.<br />Proximate composition, content of minerals, content of total polyphenols and quantitative and qualitative composition of polyphenols were investigated in both, flour samples and produced uncooked and cooked tagliatelle samples. Antiradical activity on DPPH radicals, and content of less favourable compounds, phytic acid and HMF, have been tested, as well.<br />Tagliatelle physical properties, dimensions, cooking properties, colour and textural properties were determined by instrumental and sensory methods. Tagliatelle acceptability was evaluated by the consumers. The obtained results indicate that wholegrain buckwheat flour (autoclaved or non-treated) incorporation into tagliatelle formulation led to an improvement of nutritional and functional profiles of tagliatelle samples, followed by greater or lesser deterioaration of sensory profile, depending on substitution level and type of wholegrain buckwheat flour.</p>
8

Modélisation des Écoulements en Surface et Souterrains : vallée de la Punaru'u – Tahiti / Modelling Flows Surface and Underground : Valley Punaruu - Tahiti

Aureau, Mathieu 24 September 2014 (has links)
La vallée de la Punaru’u est le second bassin versant, par sa taille, de la Polynésie française. Abritant la plusgrande zone industrielle du Pays, la vallée de la Punaru’u est emblématique des impacts de l’anthropisation sur le milieu naturel. L’exploitation de sa ressource en eau est au centre des préoccupations des industriels et des collectivités locales. L’objectif du projet était de mieux définir et de mieux comprendre les transferts d’eau dans le sol sous la zone industrielle et d’estimer l’impact des activités humaines sur la ressource en eau. En s’appuyant sur la définition des caractéristiques hydrodynamiques du sol une première partie du travail s’est concentrée à faire le lien avec les propriétés texturales et structurales du sol. Cette approche physique et analytique a permis d’ouvrir la voie à un protocole d’acquisition de données novateur basé sur les propriétés texturales du sol. Ce résultat a l’avantage de résoudre les problèmes d’échelle et de s’affranchir d’une dépendance aux conditions initiales et limites qui habituellement handicape l’interprétation des mesures des paramètres hydrodynamiques du sol.Une seconde phase de travail s’est concentrée sur l’analyse statistique des données hydrologiques. Il en résulte un schéma rénové des dynamiques hydrologiques et hydrogéologiques dans la basse vallée de la Punaru’u. D’un point de vue quantitatif, la ressource en eau s’épuise beaucoup plus en surface et dans les premiers mètres du sol que dans les aquifères plus profonds.L’approche analytique et l’interprétation hydrogéologique ont permis finalement de paramétrer une modélisation du sous-sol de la zone industrielle basée sur le solver ModFlow. / Punaru'u’s valley is the second watershed by size of French Polynesia. The valley hosts the most important industrial area of the country. The area is becoming an emblematic area because of urbanization impacts on natural environment. Exploitation of water resources is a central preoccupation.The aim of the present study is to analyze and to understand the surface and soil water transfer processes allowing for quantifying its vulnerability to the impact of human activities. Using a theoretical methodology especially developed for the characterization of hydrodynamic soil characteristics, the first part of this work is focused on the relation between textural and structural soil properties. Physical and analytical concepts are used to find a way to open a new data provision strategy based on the knowledge of measurable textural soil properties. The approach provides an original solution for tackling the important scale problem that affects most integrated modeling schemes used to describe hydrological flow processes at watershed scale. Second part of this work is focused on the statistical analysis of the hydrological field data. The results give a new insight in the hydrological and hydrogeological flow processes of the lower part of the Punaru'u valley. A quantitative interpretation shows how soil water resources are affect by human activities. The three alluvial aquifers situated in the first 40 m from the soil surface are all connected. The analytical approach and the hydrogeological interpretation allow for setting up a modeling scheme based on the “ModFlow” solver; the model is able to reproduce the hydrological flow processes of the lower part of thePunaru’u valley.
9

Alginate : a versatile biopolymer for functional advanced materials / Alginate : un biopolymère polyvalent pour des matériaux fonctionnels avancés

Pettignano, Asja 19 September 2016 (has links)
Les alginates, des polysaccharides produits par les algues brunes, sont des copolymères à blocs linéaires, formés d’unités mannuronate (M) et guluronate (G). En raison de leur abondance naturelle, prix et propriétés physicochimiques avantageuses, les alginates représentent une classe de biopolymères très intéressante et relativement inexplorée pour des applications dans le domaine des matériaux avancés. Dans ce contexte, le présent travail vise à enrichir la gamme des applications des matériaux dérivés d’alginates, en exploitant les propriétés de cette classe de polysaccharides naturels. En particulier, la préparation de matériaux à base d'alginate pour la catalyse, l'adsorption et le domaine biomédical a été étudiée, avec des résultats encourageants dans toutes les applications testées. L'utilisation bénéfique de l'acide alginique en catalyse hétérogène a été démontrée, en tant que promoteur de réaction et support pour l’hétérogénéisation d'un organocatalyseur. L'activité du catalyseur a été trouvée très dépendante de l'accessibilité des groupes fonctionnels, mettant en évidence l’avantage de l’emploi de formulations plus accessibles. La texturation des alginates a été aussi avantageuse dans la préparation de matériaux pour applications en flux. Des mousses d'acide alginique, avec une structure hiérarchique macro-mésoporeuse, ont été développées à cet effet. Une caractérisation précise des matériaux a été réalisée, afin d'optimiser la procédure de préparation et de corréler les propriétés texturales obtenues avec les paramètres utilisés. L'intérêt dans l’utilisation de mousses à base d'acide alginique a été démontré dans une application modèle, l'adsorption de bleu de méthylène à partir de solutions aqueuses, à la fois en batch et en flux. La possibilité de modifier facilement les groupes fonctionnels de l’alginate, couplée avec la nature biocompatible et biodégradable de ces biopolymères, a finalement été exploitée pour le développement de gels auto-réparants, obtenus grâce à la formation de deux types d'interactions covalentes dynamiques : base de Schiff et ester de boronate. Les deux systèmes examinés ont présenté une remarquable habilité à se reconstruire après un dégât, même si l'ampleur de la reconstruction et la stabilité des gels étaient fortement dépendantes des paramètres de préparation des gels et des conditions environnementales utilisées. Les résultats obtenus dans le cadre de cette étude démontrent clairement comment la compréhension et un emploi conscient des propriétés physico-chimiques des alginates peuvent maximiser le potentiel que cette ressource durable dans le domaine de la chimie des matériaux. / Alginates, polysaccharides produced by brown algae, are linear block-copolymers formed by mannuronate (M) and guluronate (G) units. Because of their huge natural abundance, cheapness and physicochemical properties, alginates represent a highly attractive and still relatively unexplored class of biopolymers for applications in the field of advanced materials. In this context, the present work aimed to enrich the range of possible applications of alginate-derived materials, making the most of the peculiar features of this class of natural polysaccharides. In particular, the preparation of alginate-based active materials to be employed in the catalysis, adsorption and biomedical field was studied, achieving encouraging results in all the tested applications. The beneficial use of alginic acid in heterogeneous catalysis, both as reaction promoter and as support for the heterogeneization of an organocatalyst, was demonstrated. The activity of the material was found highly dependent on the accessibility of the active functions, highlighting the advantage of employing more accessible alginate formulations. The texturation of alginates was further advantageous for the preparation of materials with improved flowability. Alginic acid foams, bearing a hierarchical macro-mesoporous structure were developed by means of a simple procedure. Accurate characterization was performed to optimize the preparation procedure and to correlate the textural properties of the obtained materials with the parameters used. The interest of the prepared alginic acid foams was demonstrated in a model application, the adsorption of methylene blue from aqueous solutions, both in batch and in flow conditions. The possibility to easily modify alginate functional groups, coupled with the biocompatible and biodegradable nature of alginates, was finally employed for the development of self-healing gels, thanks to the formation of two types of dynamic covalent interactions: Schiff base and boronate ester bonds. Both the examined systems presented a marked ability to recover after damage, even if the extent of the recovery and the stability of the gels was highly dependent on the preparation parameters and environmental conditions used. The results obtained in the course of this study clearly demonstrate how a full comprehension and conscious employment of alginate physicochemical properties can maximize the potential of this sustainable resource in the field of material chemistry.
10

Funkcionalne karakteristike smeša maltodekstrina i namenske masti kao komponenti niskoenergetskih masnih punjenja za konditorske proizvode / Functional characteristics of vegetablefat/maltodextrin gel blends as a component for low calorie confectionery fat fillings

Hadnađev Miroslav 19 April 2012 (has links)
<p>Masna punjenja predstavljaju grupu proizvoda koje se<br />koriste u konditorskoj i pekarskoj industriji. Kako ona<br />najče&scaron;će sadrže između 30-40% masti, teži se dobijanju<br />formulacija sa redukovanim sadržajem masti. To se<br />može postići zamenom dela masne faze uz upotrebu<br />zamenjivača masti, najče&scaron;će hidrokoloida koji imaju<br />osobine slične osobinama zamenjene masti.<br />Maltodekstrini i njihovi geli mogu se koristiti kao<br />zamenjivači masti. Oni predstavljaju produkte hidrolize<br />skroba koji su rastvorljivi u vodi, mogu da poseduju<br />osobine formiranja gela, imaju slične mazive osobine<br />kao i masti i blagi i neutralni ukus.<br />U ovom radu ispitivane su reolo&scaron;ke osobine različitih<br />maltodekstrina kao i sme&scaron;a namenske biljne masti i<br />rastovora/gela maltodekstrina u odnosu 9:1. Na<br />osnovu dobijenih rezultata utvrđeno je da su od svih<br />ispitivanih komercijalnih maltodekstrina,<br />maltodekstrini <em>01970 </em>i <em>N-Lite D</em> sa namenskom biljnom<br />masti davali stabilne sisteme. Stoga su maltodekstrini<br /><em>01970</em> i <em>N-Lite D</em> kori&scaron;ćeni za dalja istraživanja.<br />Namenska biljna mast zamenjivana je sa 15 i 20%<br />gelima maltodekstrina <em>01970</em> i <em>N-lite D</em> u tri različita<br />odnosa: 16,7% gela maltodekstrina i 83,3% namenske<br />biljne masti; 33,3% gela maltodekstrina i 66,7%<br />namenske biljne masti i 50% gela maltodekstrina i<br />50% namenske biljne masti. Određivane su reolo&scaron;ke<br />osobine metodom histerezisnog postupka,<br />viskoelastične osobine, kao i teksturne osobine<br />pripremanih sme&scaron;a. Dobijeni rezultati su ukazivali da<br />prisustvo maltodekstrinskih gela u sme&scaron;i sa<br />namenskom biljnom masti utiče na pad tiksotropnosti i<br />čvrstoće i povećanje prividnog viskoziteta i<br />viskoelastičnosti ispitivanih sistema. Sve sme&scaron;e<br />namenske biljne masti i gela maltodekstrina služile su<br />kao komponenta masne faze za pripremu masnih<br />punjenja sa smanjenim sadržajem masti. Povećanjem</p><p>zamene dela masne faze maltodekstrinskim gelima u<br />masnim punjenjima uzrokovalo je povećanje<br />tiksotropnosti i čvrstoće kao i promenu boje krajnjeg<br />proizvoda. Na osnovu senzorske ocene sprovedene od<br />strane iskusnog senzorskog panela i na osnovu testa<br />prihvatljivosti od strane netreniranih potro&scaron;ača,<br />najbolje ocenjena masna punjenja bila su ona kod kojih<br />je 5% masti zamenjeno maltodekstrinskim gelima.<br />Međutim, na osnovu rezultata testa prihvatljivosti<br />uočeno je da su i sistemi sa 15% zamene masti bili<br />senzorski prihvatljivi. Takođe je i na osnovu rezultata<br />sprovedenog upitnika na uzorku od 250 ispitanika<br />utvrđeno da su potro&scaron;ači (64,4%) zainteresovani za<br />konzumiranje konditorskih proizvoda sa smanjenim<br />sadržajem masti.</p> / <p>Confectionery fat fillings are products used in<br />confectionery and baking industry. They contain<br />approximately 30-40% of fat. Due to the high fat<br />content, fat fillings have considerable high caloric<br />value. Therefore, there is a trend to decrease fat<br />content in fat filling formulation. That can be achieved<br />by replacing the portion of the fat phase with fat<br />replacers, most often with hydrocolloids having<br />characteristics which tend to mimic properties of<br />replaced fat. Maltodextrins and their gels can be used<br />as potential fat replacers. Maltodextrins represent<br />starch hydrolysis products soluble in water. Also they<br />posses gel forming ability, spreading ability similar to<br />fats, and bland and non sweet taste.<br />Rheological properties of different types of<br />maltodextrins were examined. Also, blends prepared<br />with 90 % of vegetable fat and 10% of maltodextrin<br />solution/gels were rheologically characterised.<br />According to obtained results, it was found that among<br />all tested commercial maltodextrins,<em> 01970</em> and <em>N-Lite<br />D</em> built stable systems. Therefore, they were used in<br />further measurements.<br />Vegetable fat was partially replaced by 15 and 20% of<br /><em>01970</em> and <em>N-Lite D</em> maltodextrin gels in three different<br />ratios (16.66%, 33.33% and 50% respectively). Steady<br />shear, dynamic oscillatory measurements as well as<br />textural measurements were performed. The obtained<br />results indicated that the presence of maltodextrin gels<br />in blends with vegetable fat influenced the decrease of<br />thixotropy and hardness and increase of viscosity and<br />viscoelasticity of the tested systems. All maltodextrin<br />gel/vegetable fat blends were further used for</p><p>preparation of confectionery fat fillings. The increase in<br />the amount of fat reduction resulted in the increase of<br />thixotropy and hardness and change in colour of the<br />final product. According to sensory analysis performed<br />by trained sensory panel as well as by measurement of<br />product acceptance&ndash;preference performed by<br />untrained panellists (consumers), fat filling with 5% fat<br />reduction had the highest scores. However, according<br />to product acceptance&ndash;preference measurements it<br />was estimated that the final product with 15% fat<br />reduction was also sensory acceptable. The results of<br />survey performed on 250 participants showed that<br />consumers (64.4%) were interested in consuming low<br />fat confectionery product</p>

Page generated in 0.0972 seconds