Made available in DSpace on 2015-04-17T14:49:25Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1221821 bytes, checksum: efa18dbf70d63781cbd4ec59e9e4cecc (MD5) Previous issue date: 2013-02-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In recent years, an increasing number of people have entered the fish in their diets as a healthy alternative to protein intake. Among the seafood, shrimp is one of the most important commercial products. Being a highly perishable food, some conservation methods are being researched in order to prolong their shelf life, in this work, it was investigated whether the low temperatures. The sample consisted of farmed shrimp species Litopenaeus vannamei (100-120 pieces / kg) contained in packs of 200g with four packages by treatment with the filet shrimp, chilled at 0 ± 2 ° C, divided into three parts, the first packaged packaged with 1% sodium metabisulfite, and modified atmosphere in concentrations of O2 + 0 100% CO2, 75% O2 + 25% CO2 + 60% O2 + 40% CO2, 50% O2 + 50% CO2, the second packaged without 1% sodium metabisulfite and modified atmosphere gases at the same concentrations above, both with analysis at 0, 3, 6 and 9 days storage and subjected to freezing to third subdivided into three treatments, domestic freezer (CFD) to -18 ° C. Liquid nitrogen (CNL) at -86 ° C and freeze tunnel (CTC) at -35 ° C, analysis at 0, 30, 60 and 90 days of storage. We conducted physical and chemical analysis of pH, weight loss after cooking, water holding capacity, texture, color, total volatile bases and thiobarbituric acid reactive substances, and the sensory analysis was elected as the Quality Index Method ( MIQ) and Descriptive Analysis (AD), concluding that the weather influenced the physical, chemical and sensory cold shrimp, demonstrating an increase in all the aforementioned parameters. There was a high correlation between the Quality Index (QI) and time of storage. The maximum storage time in nine days or samples chilled, packed in a modified atmosphere and treated with 1% sodium metabisulfite, six days for samples chilled, packed in a modified atmosphere without additive, and 90 days for samples frozen, was estimated based on Descriptive Analysis and Quality Index Method. / Nos últimos anos, um número cada vez maior de pessoas tem inserido o pescado em suas dietas como uma alternativa saudável à ingestão de proteínas. Dentre os alimentos marinhos, o camarão é um dos produtos de maior importância comercial. Por ser um alimento muito perecível, alguns métodos de conservação vem sendo pesquisados com o objetivo de prolongar sua vida de prateleira, neste trabalho, averiguou-se as baixas temperaturas. A amostra foi composta por camarão cultivado da espécie Litopenaeus vannamei (100-120 peças/kg) contidas em embalagens de 200g com quatro embalagens por tratamento com o filé de camarão, refrigerado a 0 ± 2 oC, subdivido em três partes, a primeira acondicionada em embalagem com metabissulfito de sódio 1%, e atmosfera modificada nas concentrações de 100 O2 + 0% CO2, 75% O2 + 25% CO2 + 60% O2 + 40% CO2, 50% O2 + 50% CO2, a segunda, acondicionada sem o metabissulfito de sódio 1% e com atmosfera modificada nas mesmas concentrações gasosas supracitadas, ambas com análises em 0, 3, 6 e 9 dias de armazenamento e, a terceiras submetidas ao congelamento, subdividida em três tratamentos: Freezer doméstico (CFD) a -18 °C; Nitrogênio líquido (CNL) a -86 °C e Túnel de congelamento (CTC) a -35 °C, análises em 0, 30, 60 e 90 dias de armazenamento. Efetuou-se análises físicas e químicas tais como pH, perda de peso pós cocção, capacidade de retenção de água, textura, cor, bases voláteis totais e substancias reativas ao ácido tiobarbitúrico, nas análises sensoriais elegeu-se o Método de Índice de Qualidade (MIQ) e Análise Descritiva (AD), concluindo-se que o tempo influenciou na qualidade física, química e sensorial do camarão resfriado, demonstrando acréscimo em todos os parâmetros supracitados. Verificou-se alta correlação entre o Índice de Qualidade (IQ) e tempo de armazenamento. O tempo máximo de armazenamento foi estimado em nove dias para as amostras refrigeradas, embaladas em atmosfera modificada e tratada com metabissulfito de sódio 1%, seis dias para as amostras refrigeradas, embaladas em atmosfera modificada sem aditivo, e 90 dias para as amostras congeladas, com base na Análise Descritiva e no Método de Índice de Qualidade.

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La texture, manifestation sensorielle des propriétés structurales, mécaniques et de surface d’un matériau constitue un paramètre clé dans l’évaluation des produits alimentaires. Elle reflète leur qualité, leur fraîcheur et influence l’acceptabilité du produit par le consommateur déterminant l’intention de ré-achat. Dans la littérature scientifique, la plupart des travaux portant sur la texture des produits céréaliers ont étudié des matrices alimentaires telles que le pain ou les biscuits mais plus rares sont les travaux sur les gâteaux type cake. L’objectif de ce travail est donc de caractériser le moelleux d’un produit de type cake de sa mise en place à son évolution au cours de la conservation du produit au moyen de méthodes instrumentales et sensorielles. Dans un premier temps, nous avons étudié l’influence de la nature de la farine, du procédé de fabrication et de l’aération des produits sur caractère moelleux au travers de méthodes instrumentales et sensorielles. La caractérisation instrumentale des produits moelleux et la structure de leur mie ont été évaluées par des mesures rhéologiques (texturomètre, DMTA) et d’imagerie (XR-Tomography). La caractérisation sensorielle a été menée par l’établissement d’un profil sensoriel de la texture avec un panel entraîné évaluant l’aspect des produits et les sensations perçues au toucher et en bouche. Dans un second temps, nous avons étudié les propriétés fonctionnelles des farines et de leurs composants en milieu modèle et complexe par différentes méthodes physico-chimiques (rhéologie des pâtes, analyse enthalpique différentielle, microscopie, diffraction RX). Enfin, les mesures sensorielles et instrumentales ont été mises en relation via une analyse factorielle multiple dans le but de déterminer des méthodes instrumentales permettant de caractériser le caractère moelleux des produits de type cake. Les résultats montrent que l’aération de la mie et la composition de la farine sont les facteurs clés du moelleux dans ce type de produit. L’évaluer et le sélectionner sur la base de ses caractéristiques physico-chimiques (élasticité, fermeté, aération) s’avère possible compte tenu de la stabilité de sa texture au cours du temps afin de pouvoir anticiper sur l’acceptabilité du produit par le consommateur le plus tôt possible dans son processus de développement / Since texture is the manifestation of structural, mechanical and surface properties of a material, it represents a key characteristic for food materials. It reflects food quality, freshness perception influencing consumer acceptance.Studies encountered in the scientific literature that are devoted to cereal based foods texture are foremost based on bread also biscuits scarcely on cakes. This study entitled ‘study of the different factors influencing the structure and the texture of semi-humid baked aerated cereal products: sensory and instrumental dimensions of texture’ focus on cake softness characterization, set up and evolution. First, the investigation of the influence of soft wheat flour origin, making process and aeration properties on cake texture is proposed. Instrumental characterization of cake texture properties was performed through high deformation using TPA and relaxation tests. Several approaches were attempted to determine cake crumb structure including rheology, microscopy; image analysis and X Ray-Tomography. Sensory characterization of cake texture was achieved through descriptive texture profile involving establishment of our trained panel. Second, we peer into the functional properties of wheat flour also of its gluten and starch components, physico-chemical methods among which fluid rheology, differential scanning calorimetry, optic microscopy and X-Ray powder diffraction are employed. The results are discussed in terms of physical and chemical changes that cake dough ingredients undergo upon making process. This investigation highlights that several parameters are substantially involved in cake structure set up and final texture perception. Suitable flour choice (composition, components quality) and aeration management are critical factors for the elaboration of a product to be perceived the softest as possible. Also, regarding evolution of texture, it is possible to state on the selection of a product whether than another at early development stages allowing anticipate on consumer acceptance

Tactile perception is considered an important contributor to the overall consumer experience of a product. However, what physical properties that create the specifics of tactile perception, are still not completely understood. This thesis has researched how many dimensions that are required to differentiate the surfaces perceptually, and then tried to explain these dimensions in terms of physical properties, by interconnecting human perception measurements with various physical measurements. The tactile perception was assessed by multidimensional scaling or magnitude estimation, in which methods human participants assign numbers to how similar pairs of surfaces are perceived or to the relative quantity of a specified perceptual attribute, such as softness, smoothness, coarseness and coolness. The role of friction and surface texture in tactile perception was investigated in particular detail, because typically tactile exploration involves moving (at least) one finger over a textured surface. A tactile approach for measuring friction was developed by means of moving a finger over the surfaces, mounted on a force sensor. The contribution of finger friction to tactile perception was investigated for surfaces of printing papers and tissue papers, as well as for model surfaces with controlled topography. The overarching research goal of this thesis was to study, systematically, the role of texture in tactile perception of surfaces. The model surfaces displayed a sinusoidal texture with a characteristic wavelength and amplitude, fabricated by surface wrinkling and replica molding techniques. A library of surfaces was manufactured, ranging in wavelengths from 270 nm up to 100 µm and in amplitudes from 7 nm up to 6 µm. These surfaces were rigid and cleanable and could therefore be reused among the participants. To my knowledge, this is the first time in a psychophysical experiment, that the surface texture has been controlled over several orders of magnitude in length scale, without simultaneously changing other material properties of the stimuli. The finger friction coefficient was found to decrease with increasing aspect ratio (amplitude/wavelength) of the model surfaces and also with increasing average surface roughness of the printing papers. Analytical modeling of the finger’s interaction with the model surfaces shows how the friction coefficient increases with the real contact area, and that the friction mechanism is the same on both the nanoscale and microscale. The same interaction mechanism also explains the friction characteristics of tissue paper. Furthermore, it was found that the perceptions of smoothness, coarseness, coolness and dryness are satisfactorily related to the real contact area at the finger-surface interface.  It is shown that it is possible to discern perceptually among both printing papers and tissue papers, and this differentiation is based on either two or three underlying dimensions. Rough/smooth and thin/thick were the two main dimensions of surface feel found for the printing papers, whereas friction and wavelength were strongly related to the perceptual cues employed in scaling the model surfaces. These experimental results support the duplex theory of texture perception, which holds that both a “spatial sense”; used to discriminate the roughest textures from the others, and a “vibration sense”; used to discriminate among the smoother textures, are involved. The perception of what is considered rough and smooth depends on the experimental stimulus context. It is concluded that friction is important for human differentiation of surface textures below about 10 µm in surface roughness, and for larger surface textures, friction is less important or can even be neglected. The finger friction experiments also allowed the following conclusions to be drawn: (i) The interindividual variation in friction coefficients is too large to allow direct comparison; however, the trends in relative friction coefficients for a group of participants are the same. (ii) Lipids are transferred to the test surface of study, and this lowers the friction. (iii) Many of the studies point to a characteristic frequency during sliding of about 30 Hz, which is both characteristic of the resonance frequency of skin and the expected frequency associated with the fingerprints. (iv) The applied load in surface interrogation is in fact regulated in response to the friction force. The limits in tactile perception were indirectly researched by similarity scaling experiments on the model surfaces. Wrinkle wavelengths of 760 nm and 870 nm could be discriminated from untextured reference surfaces, whereas 270 nm could not. The amplitude of the wrinkles so discriminated was approximately 10 nm, suggesting that nanotechnology may well have a role to play in haptics and tactile perception. / Taktil perception bidrar starkt till den sammantagna upplevelsen av en produkt, men hur materials olika ytegenskaper påverkar och styr perceptionen är ännu inte helt klart. Den här avhandlingen undersöker hur många och vilka egenskaper som är viktiga när känslan mellan två ytor jämförs. Tillvägagångssättet är tvärvetenskapligt där fysikaliska mätningar kopplas ihop med perceptions mätningar där människor används som instrument. Två typer av perceptionsförsök har utförts, multidimensionell skalning där försökspersoner sätter siffror på hur lika två ytor känns, samt magnitud estimation där i stället intensiteten på specifika perceptuella storheter som t.ex. upplevt lenhet, upplevd mjukhet och upplevd strävhet bedömdes. Eftersom taktil perception innebär kontakt samt relativ rörelse mellan hud och ytor, har fokus i avhandlingen varit att undersöka hur friktion och ytans struktur (ytråhet) påverkar och bidrar till den taktila perceptionen. Förutom fysikaliska mätningar på friktion och ytstruktur har värmekonduktivitet, mjukhet samt olika standard mätningar inom pappersindustrin mätts. En metod för att mäta friktion mellan ett finger och olika ytor har utvecklats för att i möjligaste mån återspegla friktionskomponenten i upplevt taktil perception. Friktionskoefficienter beräknades och jämfördes mellan alla ytor. De stimuli som har studerats är tryckpapper och mjukpapper samt modellytor, gjorda för att systematiskt undersöka hur ytstruktur påverkar perceptionen. Tillverkningsmetoden för modellytorna valdes så att ytorna var tåliga och kunde tvättas och därmed återanvändas. Strukturen på ytorna bestod av ett vågformat mönster där våglängden varierade mellan 270 nm och 100 µm och amplituden mellan 7 nm och 6 µm. Enligt vår vetskap är det första gången som strukturer i de här skalorna har gjorts utan att samtidigt ändra andra material egenskaper. Friktionskoefficienten minskade med ökad kvot mellan amplituden och våglängden på modellytorna samt med ytråheten på tryckpappren. En analytisk modell tillämpades på kontakten mellan ett finger och ytorna som visade att friktionskoefficienten beror av den verkliga kontaktarean. För de mycket grövre mjukpappren uppmättes inga stora skillnader i friktion förmodligen för att kontakarean mellan de olika mjukpapprena var lika. Den faktiska kontakarean visade sig också vara viktig för perceptionen av lenhet, strävhet, torrhet och svalhet. Det visade sig vara en stor perceptuell skillnad mellan olika typer av tryckpapper och mjukpapper utifrån hur stimuli placerade sig på en taktil karta. För de tre materialen användes enbart två alternativt tre egenskaper hos materialet för att särskilja mellan alla olika par. För tryckpapper verkade en viktig dimension kunna beskrivas av alla de perceptuella och fysikaliska egenskaper som har med kontaktarean att göra, d.v.s. lenhet, svalhet, torrhet, ytråhet, värmekonduktivitet samt friktion. För att taktilt särskilja mellan olika ytor där bara strukturen är varierade, kunde friktion och våglängden relateras till spridningen i kartan. Båda studierna stödjer duplex theory of texture perception, där ett spatialt sinne används för att särskilja en av de grövre ytorna från en slät, och ett vibrationssinne för att särskilja mellan olika släta strukturer. Friktionen visade sig alltså vara en viktig fysikalisk egenskap för strukturer under åtminstone 10 µm i ytråhet. Från fingerfriktions mätningar kunde även följande slutsatser dras: (i) Stora skillnader i friktionskoefficient mellan olika personer uppmättes, men trenderna mellan olika individer var samma, vilket gör att relativa skillnader i friktion från en individ är representativa. (ii) Lipider (fingerfett) som överförs från fingret till ytan vid kontakt sänker friktionen. (iii) Frekvensinnehållet i friktionskraften varierar mellan olika ytor och den frekvenstopp som ses vid 30 Hz kan möjligtvis bero på fingrets struktur eller resonansfrekvensen på huden. (iv) Den pålagda kraften under en friktionsmätning visar sig omedvetet regleras av den friktionskraft som fingret möter under rörelse.  Hur små strukturer som kan diskrimineras har indirekt undersökts genom likhetsförsöket på modellytorna där försökspersoner skulle bedöma hur lika alla par av ytor kändes. Resultaten visade att ytorna med våglängder på 760 nm och 870 nm upplevdes olika jämfört med referens ytor utan något systematiskt mönster, medan ytan med 270 nm i våglängd inte kunde särskiljas. Amplituden på ytan som kunde diskrimineras var endast ca 10 nm, vilket indikerar att nanoteknologi mycket väl kan bidra inom haptiken och för att i framtiden kontrollera den taktila perceptionen. / <p>QC 20121026</p>