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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.
1

Segmentace trhu bezlepkových protravin / Gluten Free Food Market Segmentation

Gruberová, Anna January 2013 (has links)
This thesis contains information about gluten free food market. It describes all main actors and also different types of business which can sell or manufacture gluten free food. Great emphasis is placed on understanding needs of "gluten free" customers identifying behavior which differentiate them inside this segment and also between regular customers. It also discovers opportunities and challenges on this market. Based on collected information it predicts possible future development.
2

Evaluation and optimization of four real-time PCRs, using TaqMan-probes, for detection of and discrimination between barley, oat, rye and wheat

Björklund, Kristofer January 2008 (has links)
<p>Coeliac disease is a chronic inflammatory disease treated with a gluten-free diet, excluding barley, rye and wheat. Hence, there is a demand for methods able to detect gluten in foods in order to ensure correct labeling of products. According to the Codex Alimentarius Commission, 20ppm gluten is the maximum amount allowed in food labeled gluten-free.</p><p>PCR can detect DNA from cereals in food. Four real-time PCR-systems,</p><p>using TaqMan®-probes for detection of barley, oat, rye and wheat were optimized and evaluated. Evaluations were carried out using seeds. Primers were targeted to genes coding for prolamines, seed storage proteins. PCR-systems targeted to barley, oat and wheat were shown to be specific for the cereals corresponding to each system. The system targeted to rye showed cross-reactions with durum wheat and spelt wheat. Detection limits were 50pg, corresponding to <10 haploid genome copies for each cereal. All systems were able to detect 250ppm amounts of DNA, most likely even smaller amounts are detectable. All systems showed an amplification efficiency of ≥95%.</p><p>Systems for detection of barley, oat and wheat are ready for further evaluation, using food products as samples. The rye system however, needs to be re-designed before further evaluation can take place.</p>
3

Evaluation and optimization of four real-time PCRs, using TaqMan-probes, for detection of and discrimination between barley, oat, rye and wheat

Björklund, Kristofer January 2008 (has links)
Coeliac disease is a chronic inflammatory disease treated with a gluten-free diet, excluding barley, rye and wheat. Hence, there is a demand for methods able to detect gluten in foods in order to ensure correct labeling of products. According to the Codex Alimentarius Commission, 20ppm gluten is the maximum amount allowed in food labeled gluten-free. PCR can detect DNA from cereals in food. Four real-time PCR-systems, using TaqMan®-probes for detection of barley, oat, rye and wheat were optimized and evaluated. Evaluations were carried out using seeds. Primers were targeted to genes coding for prolamines, seed storage proteins. PCR-systems targeted to barley, oat and wheat were shown to be specific for the cereals corresponding to each system. The system targeted to rye showed cross-reactions with durum wheat and spelt wheat. Detection limits were 50pg, corresponding to &lt;10 haploid genome copies for each cereal. All systems were able to detect 250ppm amounts of DNA, most likely even smaller amounts are detectable. All systems showed an amplification efficiency of ≥95%. Systems for detection of barley, oat and wheat are ready for further evaluation, using food products as samples. The rye system however, needs to be re-designed before further evaluation can take place.
4

Modificação enzimática da farinha de grãos quebrados de arroz para produção de alimento sem glúten / Enzymatic modification of grain flour broken rice to produce food without gluten

FERREIRA, Suzane Martins 09 March 2012 (has links)
Made available in DSpace on 2014-07-29T16:16:35Z (GMT). No. of bitstreams: 1 SUZANE MARTINS FERREIRA.pdf: 4234283 bytes, checksum: a9da923ebc0cff306eed06dbcfb32a27 (MD5) Previous issue date: 2012-03-09 / The rice (Oryza sativa L.) is a cereal consumed worldwide, and the energy base of food, constituting about 23% of total daily calories and about 14% of the protein. The grains are broken rice by-products generated in the processing industry for the processing of rice and cereals have been used for the production of modified starch to be ideal source of low cost, easily obtainable and allows industrial production. The purpose of this study was to determine the enzymatic hydrolysis of grain flour broken rice flour to produce a modified with &#945;-amylase and amyloglucosidase, and drying temperatures (40, 80, 100, 120 and 140 ° C) in its physical, chemical and technological. It also aimed to develop a product similar to flour gluten-free rice milk, by means of mixture design, using flour as components of broken grains of rice and dried enzymatically modified (FDM), milk powder and sugar. The analyzes in FDM were broken and composition, determination of reducing sugars, glucose, color coordinates, solubility and absorption in water and milk analysis and scanning electron microscopy. The enzymatic hydrolysis at 40 ° C was more efficient using 2U of &#945;-amylase / g flour in time of 2 hours and 3U of amyloglucosidase / g of flour in the time of three hours of hydrolysis. The FDM at 40, 80 and 100 ° C showed a reducing sugar of 111.37, 108.15 and 116.04 mg / g of flour and glucose 83.20, 75.90 and 77.30 mg / g flour respectively, which are significantly higher than the grain flour fresh broken and the other drying temperatures tratamentos.As influence the composition of the FDM at different temperatures, an increase in lipid content with increasing drying temperature and changes in its structure. The FDM 40, 80 and 100 ° C had a content of reducing sugars, glucose, solubility in water and in milk significantly larger than the grain flour broken.The FDM from 100 ° C exhibited characteristics of a flour resistant to shear force, and stable to heating at lower temperatures. They also had a darker color with yellow tones and slightly red in the other treatments. The product similar to the rice flour milk was selected with the formulation 10% sugar, 31% milk powder and 59% of the FDM 100 ° C, and evaluated for composition and quality parameters. The formulation presented with sensory acceptance score of 7.95, good strength characteristics, technological characteristics as an index of solubility in water and milk, color coordinates and nutritional composition similar to milk commercial flour. / O arroz (Oryza sativa L.) é um cereal consumido em todo o mundo, sendo a base energética da alimentação humana, constituindo cerca de 23% das calorias diárias totais e cerca de 14% das proteínas. Os grãos quebrados de arroz são subprodutos gerados na indústria processadora de arroz durante o beneficiamento do cereal e tem sido utilizados para produção de amidos modificados, sendo ideal por ser fonte de baixo custo, fácil aquisição e que permite produção industrial. O propósito deste trabalho foi determinar o efeito da hidrólise enzimática da farinha de grãos quebrados de arroz para produção de uma farinha modificada, com &#945;-amilase e amiloglucosidase, e das temperaturas de secagem (40, 80, 100, 120 e 140°C), em suas características físicas, químicas e tecnológicas. Também teve como objetivo desenvolver um produto similar à farinha láctea de arroz sem glúten, por meio do delineamento de misturas, utilizando como componentes a farinha de grãos quebrados de arroz modificada enzimaticamente e seca (FMS), leite em pó e açúcar refinado. As análises realizadas nas farinhas de grãos quebrados e nas FMS foram composição centesimal, determinação de açúcares redutores, glicose, coordenadas de cor, solubilidade e absorção em água e leite e análise de microscopia eletrônica de varredura. A hidrólise enzimática na temperatura de 40°C foi mais eficiente utilizando as concentrações de 2UE de &#945;-amilase /g de farinha no tempo de 2 horas e 3,5UE de amiloglucosidase /g de farinha no tempo de 3 horas de hidrólise. As FMS a 40, 80 e 100°C apresentaram teores de açúcares redutores de 111,37; 108,15 e 116,04 mg/g de farinha e glicose de 83,20; 75,90 e 77,30 mg/g de farinha respectivamente, sendo estes significativamente maiores em relação a farinha de grãos quebrados in natura e aos demais tratamentos.As temperaturas de secagem influenciaram na composição centesimal da FMS em diferentes temperaturas, apresentando um aumento no teor de lipídios com o aumento da temperatura de secagem e modificação em sua estrutura. As FMS em 40, 80 e 100°C apresentaram conteúdo de açúcares redutores, glicose, solubilidade em água e em leite significativamente maiores que a farinha de grãos quebrados. As FMS a partir de 100°C apresentaram características de uma farinha resistente a força de cisalhamento, ao aquecimento e estável a temperaturas mais baixas. Também apresentaram uma coloração mais escura, com tonalidades amarelas e levemente vermelhas em relação aos demais tratamentos. O produto similar à farinha láctea de arroz foi selecionado, com a formulação de 10% de açúcar, 31% de leite em pó e 59% de FMS a 100°C, e avaliados quanto à composição centesimal e parâmetros de qualidade. A formulação apresentou aceitação sensorial com score de 7,95, boas características de firmeza, características tecnológicas como índice de solubilidade em água e leite, coordenadas de cor e composição nutricional semelhantes às farinhas lácteas comerciais.
5

Análisis del uso y consumo de alimentos aptos para celíacos en la oferta gastronómica a nivel mundial / Analysis of the use and consumption of foods suitable for coeliac in the gastronomic offer worldwide

Cavero Bravo, Maira Alejandra, Saenz Peralta, Daniela Valeria 14 December 2020 (has links)
La investigación presenta una síntesis académica sobre el rol que cumplen los restaurantes y los negocios gastronómicos en satisfacer la demanda de alimentos libres de gluten a nivel mundial. Los alimentos libres de gluten están evolucionando y su llegada al mercado es cada vez más rápida tanto en restaurantes, tiendas naturistas y en muchos de los negocios que se dedican a la producción de alimentos y bebidas. Además, estos alimentos benefician a los celíacos, un nicho de mercado poco explorado, que se caracteriza por tener una estricta dieta libre de gluten por el resto de su vida. Se trata de una investigación basada en la revisión bibliográfica descriptiva y evaluativa. El principal aporte de esta investigación es el de presentar un análisis del uso y consumo de los alimentos aptos para celíacos en la oferta gastronómica a nivel mundial. Se presenta información sobre la variedad de productos que existen aptos para celíacos, así como la variedad de alimentos sin gluten que son ofrecidos en restaurantes, pastelerías y heladerías internacionales. Los principales hallazgos son que los productos, restaurantes y negocios aptos para celíacos a nivel mundial han aumentado, a partir de lo cual debe existir un mayor control y supervisión de todos estos para garantizar una mayor seguridad para los afectados por la enfermedad celíaca. Pese a ello, en Perú aún es poca la oferta de alimentos orientada a este nicho de mercado en comparación con otros países. / The research presents an academic synthesis of the role of restaurants and food businesses in meeting the demand for gluten-free foods worldwide. Gluten-free foods are evolving and reaching the market faster and faster in restaurants, health food stores and in many food and beverage businesses. In addition, these foods benefit coeliac, a little explored niche market, which are typical by having a strict gluten-free diet for the rest of their lives. The main contribution of this research is to present an analysis on the use and consumption of foods suitable for coeliac in the gastronomic offer worldwide. Information presented on the variety of products that exist suitable for coeliac, as well as the variety of gluten-free foods that are presented in restaurants, bakeries and international ice cream shops. A descriptive-evaluative bibliographic review will be apply to this research. The main findings are that products, restaurants and businesses suitable for coeliac worldwide have increased, from which there must be greater control and monitoring of all these to ensure greater safety for those affected by celiac disease. Despite this, in Peru there is still little food supply oriented to this market niche compared to other countries. / Trabajo de investigación
6

Novel Techniques in Sensory and Consumer Research Applied to Understand Gluten-Free Products Perception

Puerta Gil, Patricia 24 March 2022 (has links)
Tesis por compendio / [ES] El trabajo de investigación realizado en esta tesis se ha centrado en la aplicación de técnicas recientes e innovadoras en el estudio de la percepción de productos sin gluten. Primero, se estudió cómo tratar la información que hay en Twitter para conocer las opiniones de los consumidores sobre "sin gluten". Los temas más relevantes fueron 5 productos (pan, tarta, galleta, pizza, cerveza), situaciones de consumo, recomendaciones, lugares y aspectos relacionados con la celiaquía. Para explorar automáticamente la información de Twitter, se estudió utilizar redes de co-ocurrencia, que fueron útiles para interpretar los tweets, representar los aspectos más relevantes (ocurrencia) y ponerlos en contexto y en relación con otros (co-ocurrencia). Se observó que es posible automatizar sin un pre-tratamiento manual, permitiendo analizar de forma efectiva gran cantidad de información disponible online. Después, se estudiaron diferentes panes comerciales sin gluten en cuanto al comportamiento en boca para entender mejor los factores involucrados en la percepción de textura. Los panes (5 sin gluten; 2 normales) se caracterizaron en cuanto a propiedades mecánicas, estructura, fragmentación, saliva incorporada y consistencia y adhesividad del bolo. Las sensaciones de textura variaron a lo largo de la masticación, dependiendo de su estructura inicial, propiedades mecánicas, fragmentación, formación de bolo o actividad oral. Posteriormente, se estudió cómo los cambios en la estructura de panes sin gluten obtenidos por modificaciones en panificación (tiempo de fermentación e hidratación) afectan al procesamiento y actividad oral y las sensaciones de textura, que variaron principalmente según el tiempo de fermentación. Especialmente al principio, las diferencias en las sensaciones de textura se explicaron por las diferencias en la estructura y fragmentación en boca. Por último, se estudió la atención visual (con eye-tracking) y la respuesta de consumidores celíacos a paquetes de pan sin gluten, observando que el tipo de marca y la presencia del logo de certificación sin gluten influían en lo que miran. Todos los panes les dieron confianza, sin afectar la presencia del logo, pero condicionando lo que miran. El tipo de marca afectó la confianza y la expectativa de aceptabilidad, que fueron más altas para marcas específicas de sin gluten. La aceptabilidad también se explicó por otras características de cada pan. Se estudió la atención visual (eye-tracking) y las motivaciones de niños celíacos y sus padres al comprar galletas en comparación con los no celíacos. El patrón de fijación cambió en niños y padres: los niños celíacos se fijaron más en ingredientes, palabras y símbolos sin gluten, y menos en la imagen de las galletas; los padres de niños celíacos se fijaron más en ingredientes y símbolo sin gluten, y menos en la imagen de la galleta, nombre, dibujo e información nutricional. Para todos los niños y padres, lo más importante fue elegir una galleta que les gustara, pero solo los niños celíacos mostraron interés en la marca y por probar un producto nuevo. Otro motivo importante para los padres fue la salud, pero por diferentes atributos (padres de celíacos: certificación sin gluten o lista corta de ingredientes; padres de no celíacos: bajo en azúcar o grasa). El precio o la confianza fueron relevantes solo para los padres de niños celíacos. Esta Tesis ha aportado conocimiento sobre el uso y la practicidad de técnicas recientes en ciencia sensorial y del consumidor. La investigación confirma que se puede conseguir una comprensión plena de la compleja respuesta del consumidor recabando información desde perspectivas muy distintas. Sin embargo, para responder a cuestiones específicas en investigación, cada una de estas técnicas (análisis de las redes sociales, estudio del procesado oral de los alimentos o la técnica eye-tracking) puede contribuir de forma individual a entender mejor la aceptabilidad o la elección de alimentos del consumidor. / [CA] El treball de recerca realitzat en esta tesi s'ha centrat en l'aplicació de tècniques recents i innovadores en l'estudi de la percepció de productes sense glútens. Primer, es va estudiar com tractar la informació que hi ha en Twitter per a conéixer les opinions dels consumidors sobre "sense glútens". Els temes més rellevants van ser 5 productes (pa, pastís, galeta, pizza, cervesa), situacions de consum, recomanacions, llocs i aspectes relacionats amb la celiaquia. Per a explorar automàticament la informació de Twitter, es va estudiar utilitzar xarxes de co-ocurrència, que van ser útils per a interpretar els tuits, representar els aspectes més rellevants (ocurrència) i posar-los en context i en relació amb uns altres (co-ocurrència). Es va observar que és possible automatitzar sense un pre-tractament manual, permetent analitzar de manera efectiva gran quantitat d'informació disponible en línia. Després, es van estudiar diferents pans comercials sense glútens quant al comportament en boca per a entendre millor els factors involucrats en la percepció de textura. Els pans (5 sense glútens; 2 normals) es van caracteritzar quant a propietats mecàniques, estructura, fragmentació, saliva incorporada i consistència i adhesivitat de la bitla. Les sensacions de textura van variar al llarg de la masticació, depenent de la estructura inicial, propietats mecàniques, fragmentació, formació de bitla o activitat oral. Posteriorment, es va estudiar com els canvis en l'estructura de pans sense glútens obtinguts per modificacions en panificació (temps de fermentació i hidratació) afecten el processament i activitat oral i les sensacions de textura, que van variar principalment segons el temps de fermentació. Especialment al principi, les diferències en les sensacions de textura es van explicar per les diferències en l'estructura i fragmentació en boca. Finalment, es va estudiar l'atenció visual (amb eye-tracking) i la resposta de consumidors celíacs a paquets de pa sense gluten, observant que el tipus de marca i la presència del logotip de certificació sense gluten influïen en el que miren. Tots els pans els van donar confiança, sense afectar la presència del logotip, però condicionant el que miren. El tipus de marca va afectar la confiança i l'expectativa d'acceptabilitat, que van ser més altes per a marques específiques de sense glútens. L'acceptabilitat també es va explicar per altres característiques de cada pa. Es va estudiar l'atenció visual (eye-tracking) i les motivacions de xiquets celíacs i els seus pares en comprar galetes en comparació amb no celíacs. El patró de fixació va canviar en xiquets i pares: els xiquets celíacs es van fixar més en ingredients, paraules i símbols sense glútens, i menys en la imatge de les galetes; els pares de xiquets celíacs es van fixar més en ingredients i símbol sense gluten, i menys en la imatge de la galeta, nom, dibuix i informació nutricional. Per a tots els xiquets i pares, el més important va ser triar una galeta que els agradara, però només els xiquets celíacs van mostrar interés en la marca i per provar un producte nou. Un altre motiu important per als pares va ser la salut, però per diferents atributs (pares de celíacs: certificació sense gluten o llista curta d'ingredients; pares de no celíacs: baix en sucre o grassa). El preu o la confiança van ser rellevants solo per als pares de xiquets celíacs. Esta Tesi ha aportat coneixement sobre l'ús i la practicitat de tècniques recents en ciència sensorial i del consumidor. La investigació confirma que es pot aconseguir una comprensió plena de la complexa resposta del consumidor recaptant informació des de perspectives molt diferents. No obstant això, per a respondre a qüestions específiques en investigació, cada una d'estes tècniques (anàlisis de les xarxes socials, estudi del processament oral dels aliments o la tècnica eye-tracking) pot contribuir de manera individual a entendre millor l'acceptabilitat o l'elecció d'aliments del consumidor. / [EN] The research of this thesis is focused on the application of recent and innovative techniques to study the perception of gluten-free products. First, it was studied how to manage the information available on Twitter to get consumers' opinions about "gluten-free". The most relevant topics when talking about gluten-free on Twitter were five products (bread, cake, cookie, pizza, beer), situations of consumption, recommendations, places, and aspects related to coeliac condition. To automatically explore the information from Twitter, the possibility to use co-occurrence networks was studied. Co-occurrence networks were useful for interpreting tweets' content, representing the most relevant aspects mentioned (occurrence) and putting them into context and in relation to others (co-occurrence). It was found that automated without manual pre-treatment of text is possible, as an efficient analysis of big amounts of online data. Secondly, different commercial gluten-free breads were studied in terms of in-mouth behaviour to better understand the factors involved in texture perception. The breads (5 gluten-free; 2 regular) were characterised regarding mechanical properties, structure, fragmentation, saliva incorporated, and bolus consistency and adhesiveness. Texture sensations varied along mastication, depending on their initial structure, mechanical properties, fragmentation pattern, bolus formation or oral activity. Subsequently, it was studied how changes in structure of gluten-free breads achieved by modifications in breadmaking (fermentation time and hydration) affect oral processing, oral activity and texture sensations. Oral behaviour and texture perception varied mostly according to the fermentation time. Especially at the beginning, differences in texture sensations were explained by the differences in structure and how it fragmented in mouth. Lastly, visual attention (with eye-tracking technique) and response of coeliac consumers to gluten-free bread packages were studied, finding that the type of brand and presence of gluten-free certification logo influenced the visual behaviour. All gluten-free breads were perceived as trustworthy, not being affected by the presence of gluten-free certification logo, but conditioning the visual behaviour. The type of brand affected trust and expected acceptability, being both higher for brands specific of gluten-free. Liking was also explained by other individual characteristics of breads. Visual behaviour and motivations of coeliac children and their parents when purchasing biscuits were studied in comparison to non-coeliac ones. Eye-tracking showed that fixation pattern changed for coeliac children and their parents. Coeliac children fixated more on ingredients, gluten-free words and symbols, and less on biscuit image. Parents of coeliac children fixated more on ingredients and the gluten-free symbol, and less on biscuit image, product name, cartoon, and nutritional information. For all children and parents, liking was the most important reason for choosing a biscuit, but only coeliac children showed interest in brand and unknown products. Other important motivation for parents was health, but the attributes were different (parents of coeliac group: having gluten-free certification or a short ingredients list; parents of non-coeliac group: low sugar or fat contents). Price or trust were relevant motivations only for parents of celiac children. On overall, this Thesis provided knowledge about the usage and practicality of recent techniques or approaches in sensory and consumer science. This investigation confirms that a full understanding of complex consumer's response can be achieved by gathering consumer's information from different perspectives. However, for answering specific research questions, these different tools (social media exploration, food oral processing approach or eye-tracking technique) can individually contribute to better understand consumer acceptability or food choice. / Puerta Gil, P. (2022). Novel Techniques in Sensory and Consumer Research Applied to Understand Gluten-Free Products Perception [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182293 / TESIS / Compendio

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