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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.
71

Development of a Screening Methodology for the Analysis of Rhodamine B in Foodstuffs

Knecht, George T 01 January 2023 (has links) (PDF)
Synthetic dyes that are used as color additives in foodstuffs are regulated by the Food and Drug Administration (FDA) under the Food, Drug, and Cosmetic Act (FD&C). The use of synthetic dyes not approved by the FDA, or the addition of dyes approved by the FDA above their maximum concentration limits in foodstuffs necessarily constitutes illegal food adulteration. Recently, rhodamine B (RhB), a bright-pink synthetic dye not approved for use in foodstuffs, has become an adulterant of interest due to its discovery in a large variety of food samples, and its identity as a potential carcinogen. Numerous chromatographic and spectroscopic methods have been developed for the analysis of RhB in food samples, as well as standard methods available for the analysis of synthetic dyes. However, due to the complexity of real food samples and the chemical diversity of synthetic dye concomitants, comprehensive chromatographic methods tend to be time consuming and expensive. Herein, we report a method for the determination of RhB in foodstuffs for the screening of real samples prior to subsequent full-blown chromatographic analysis, saving valuable time and resources. This screening method employs thin-layer chromatography (TLC) as a separation method, and, due to the strong yellow-orange fluorescence exhibited by RhB when excited with ultraviolet or green light, direct fluorescent measurement of RhB on the TLC plate using a fiber optic probe coupled to a commercial spectrofluorometer or to an instrumental set up for laser-induced fluorescence measurements. Qualitative analysis of RhB is based on its retardation factor, excitation and fluorescence spectra, and fluorescence lifetime. Quantitative measurements are made directly from the TLC plate to provide analytical figures of merit comparable to traditional fluorometric methods in liquid solution. The ability of the new method to determine RhB in food samples is then demonstrated with the analysis of chili powder.
72

Applications of supercritical fluid technologies to the analysis of food components

Calvey, Elizabeth Madigan January 1989 (has links)
Supercritical fluid (SF) technologies are being investigated extensively by the food industry for a variety of applications. Carbon dioxide in the supercritical state is of particular interest to the food industry due to its extremely low toxicity in comparison with organic solvents. Three applications of chromatography or extraction employing SFs in the analysis of food components and natural products were investigated. These applications related to carbohydrate, lipid, and coumarin derivative analyses. The peracetylated nitrogen derivatives of carbohydrates were analyzed by supercritical fluid chromatography (SFC) with flame ionization detection (FID), Fourier-transform infrared (FT-IR) detection, and mass spectrometry (MS) detection. Although reports in the literature indicated that only one derivatized component was detected under GC conditions, the SFC analysis of peracetylated aldonitrile derivatives of monosaccharides resulted in detection of multiple reaction products. The identification of the peracetylated nitrile and acyclic oxime was accomplished using both SFC/FT-IR and SFC/MS. The spectroscopic data indicated that an additional reaction product was a peracetylated cyclic oxime. The data was not conclusive enough to determine if the structure contained a pyranose or furanose ring. Changes in chemical composition of vegetable oils due to processing were observed employing SFC/FT-IR. Refined soybean oil and soybean oil that was hydrogenated with a NI or a Ni-S catalyst were analyzed. SFC/FT-IR provided an opportunity to determine the extent of unsaturation and isomerization in a single analysis. The C-H deformation of trans R₁HC=CHR₂ groups was observed at 972 cm⁻¹. The double bond in the cis configuration was evident by absorptions above 3000 cm⁻¹l. On-line FT-IR spectra of triacylglycerols and free fatty acids readily revealed conversion to trans isomers in those samples that were hydrogenated with the Ni-S. Quantitation was not possible due to the incomplete resolution of the cis and trans isomers present in the hydrogenated samples. Apparent threshold densities were determined for a series of coumarin derivatives using a supercritical fluid chromatograph with a flame ionization detector. The extraction cell was a LC stainless steel precolumn. Milligram quantities of the model compounds were extracted. Functionality, extraction temperature, and matrix affected the measured threshold densities of the compounds. The addition of two hydroxyl groups onto the coumarin structure caused the compound to be unextractable at 60°C and densities up to 0.90 g/mL. For those compounds that were completely extracted, coumarin, 7-methoxycoumarin, 3-phenylcoumarin, and psoralen, the apparent threshold density increased with increasing melting point. The melting or decomposition points of those compounds that were partially extracted ranged between 200 and 240°C. For those compounds that were not extracted, under the constraints of the experiment, the melting or decomposition points were greater than 240°C. A higher extraction temperature resulted in a lower threshold density. Corn starch was found to be a noninteractive matrix. / Ph. D.
73

Authentication of Stemona root, oilfish, crocodile meat and frog oviduct.

January 2008 (has links)
Ling, Ka Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 124-157). / Abstracts in English and Chinese. / Acknowledgement --- p.ii / Abstract --- p.iv / 摘要 --- p.vii / Table of content --- p.ix / List of figures --- p.xiii / List of tables --- p.xv / Abbreviations --- p.xvi / Chapter 1 --- Food authentication --- p.1 / Chapter 1.1 --- Introduction and definition --- p.1 / Chapter 1.2 --- Importance of species identification in food authentication --- p.3 / Chapter 1.3 --- Methods for species identification in food authentication --- p.8 / Chapter 1.4 --- Legislation --- p.17 / Chapter 1.5 --- Objectives --- p.19 / Chapter 2 --- Molecular authentication and antitussive bioassay of Stemona root (Baibu) and root of Asparagus filicinus (Xiao-baibu) --- p.20 / Chapter 2.1 --- Introduction --- p.20 / Chapter 2.2 --- Materials and methods --- p.22 / Chapter 2.3 --- Results --- p.34 / Chapter 2.4 --- Discussion --- p.40 / Chapter 2.5 --- Conclusions --- p.44 / Chapter 3 --- Rapid detection of oilfish and escolar in fish steaks: a tool to prevent keriorrhea episodes --- p.45 / Chapter 3.1 --- Introduction --- p.45 / Chapter 3.2 --- Materials and methods --- p.49 / Chapter 3.3 --- Results --- p.59 / Chapter 3.4 --- Discussion --- p.69 / Chapter 3.5 --- Conclusions --- p.75 / Chapter 4 --- Widespread adulteration of crocodile meat with python and water monitor meats --- p.76 / Chapter 4.1 --- Introduction --- p.76 / Chapter 4.2 --- Materials and methods --- p.78 / Chapter 4.3 --- Results --- p.89 / Chapter 4.4 --- Discussion --- p.96 / Chapter 4.5 --- Conclusions --- p.100 / Chapter 5 --- Authentication of dried and ready-to-eat hashima products --- p.101 / Chapter 5.1 --- Introduction --- p.101 / Chapter 5.2 --- Source species of hashima --- p.103 / Chapter 5.3 --- Materials and methods --- p.106 / Chapter 5.4 --- Results --- p.116 / Chapter 5.5 --- Discussion --- p.119 / Chapter 5.6 --- Conclusions --- p.121 / Chapter 6 --- General conclusions --- p.122 / Chapter 6.1 --- Key findings --- p.122 / Chapter 6.2 --- Applications and implications --- p.123 / Chapter 7 --- References --- p.124
74

Consumption of foods prepared at home versus foods prepared outside of the home : differences in caloric, cholesterol, and sodium & intakes of men aged 45-54

Baltz, Kristin Nikolai January 1989 (has links)
The null hypothesis for this study was there were no differences in caloric intake, cholesterol, and sodium intakes of food prepared at home as contrasted with food prepared outside of the home when consumed by men 45-54 years old. The three dietary intakes have been associated with medical conditions that cause death in humans. This study provided information which could enable nutrition educators, foodservice managers, and men aged 45-54 who are employed at a factory to understand how consumption of these three intakes differs when foods were prepared at home as contrasted with outside of the home. Therefore, this study provided information to help lower the risk factors of heart diseases, hypertension, and obesity which are associated with caloric intake, cholesterol and sodium consumption.Participants completed three days of food frequencies and dietary records. The Sign Test was used to analyze the differences between food prepared at homeand outside of the home for caloric, cholesterol, and sodium intakes.Statistical analysis of the data revealed:(1) A significant difference in caloric intake of food prepared at home as contrasted with food prepared outside of the home when consumed by men 45-54 years old (p < 0.05).(2) No significant difference in cholesterol intake of food prepared at home as contrasted with food prepared outside of the home when consumed by men 45-54 years old (p > 0.05).(3) No significant difference in sodium intake of food prepared at home as contrasted with food prepared outside of the home when consumed by men 45-54 years old (p > 0.05). / Department of Home Economics
75

Qualidade microbiológica de amostras de açúcar mascavo / Microbiological quality of samples of brown sugar

Jesus, Daniele Almeida de 30 August 2010 (has links)
Amostras de açúcar mascavo disponíveis em diferentes estabelecimentos comerciais no município de Araras - SP foram adquiridas para análises. No total foram coletados 49 pacotes de açúcar durante um período de quatro meses. As análises foram realizadas com o objetivo de avaliar a qualidade desse produto oferecido ao consumidor. As análises microbiológicas foram realizadas considerando a pesquisa dos seguintes microrganismos: bactérias mesófilas, bolores e leveduras, esporos de bactérias termófilas flat-sour, esporos de bactérias termófilas anaeróbias produtoras de H2S, esporos de bactérias termófilas anaeróbias não produtoras de H2S, Salmonella, coliformes totais e termotolerantes. Ainda foram determinadas a umidade (%) e atividade de água das amostras. Os resultados das análises apresentaram variações nas concentrações dos microrganismos estudados, cabendo às bactérias mesófilas e aos esporos de termófilas flat-sour as contagens mais elevadas, seguidos por bolores e leveduras. Todas as marcas apresentaram ausência de Salmonella, coliformes totais e termotolerantes, atendendo a legislação brasileira. Em relação ao padrão da National Canners Association apenas as marcas A, G, H e J estavam adequadas a essas exigências, as demais estavam em desacordo. Para o padrão da International Commission for Uniform Methods of Sugar Analysis (ICUMSA), nenhuma marca obteve resultado satisfatório em relação à qualidade microbiológica. Os teores de umidade variaram de 1,94 a 3,63% e os valores de atividade de água variaram de 0,55 a 0,64, havendo diferença significativa ao nível de 5% de significância. Pelos resultados obtidos considera-se que as marcas comercializadas estão de acordo com a legislação vigente no país, porém a maioria das marcas não atende aos padrões internacionais. / Samples of brown sugar available in different establishments in the city of Araras - SP were acquired for analysis. In the total 49 packages of sugar were collected during a period of four months. The analyses were performed to evaluate the quality of that product for the consumer. Microbiological tests were performed to search the following microorganisms: mesophilic bacteria, yeasts and molds, thermophilic flat-sour spores, thermophilic anaerobic H2S-producing spores, thermophilic anaerobic non-producing H2S spores, Salmonella and total and thermotolerant coliforms. Also humidity (%) and water activity were determined for the samples. The analysis results presented variations in the concentrations of microorganisms studied, being the mesophilic bacteria and thermophilic \"flat-sour\" spores the ones with highest scores, followed by yeasts and molds. All brands showed absence of Salmonella and total and thermotolerant coliforms, in accordance with the Brazilian legislation. Regarding the National Canners Association standards, only brands A, G, H and J were suited to these demands, the others being in disagreement. For the International Commission for Uniform Methods of Sugar Analysis (ICUMSA), standards no brands obtained satisfactory results in relation to microbiological quality. The moisture content ranged from 1.94 to 3.63% and the values of water activity ranged from 0.55 to 0.64, significant difference at 5% significance level. By the results it is considered that the brands are marketed under the law of the country, but most brands do not meet international standards. Humidity rates ranged from 1.94 to 3.63% and water activity ranged from 0.55 to 0.64, with significant difference at 5% significance level. By the results obtained it is considered that all brands sold are in accordance to the laws of the country, but most brands do not meet the international standards.
76

Efeito dos processos de irradiação e germinação nos aspectos nutricionais, sensoriais e microbiológicos em grãos de soja (Glycine m ax Merril) cultivar BRS216 / Effect of irradiation and germination processes in the nutritional, sensory and microbiological in soybeans (Glycine max Merrill) cultivra BRS216

Martinez, Ana Paula Corazza 13 October 2011 (has links)
A soja (Gycine max (L.) Merril) é uma leguminosa de importante significado na alimentação humana devido seus potenciais efeitos benéficos à saúde. Devido ao crescente estímulo ao consumo de grãos de soja pela presença de diversos compostos bioativos, alguns processamentos tem sido estudados como forma de conhecer às alterações desses componetes ao longo dos processos. Diante disso, o presente estudo teve por objetivo estudar as alterações na composição sensorial e nutricional da soja cultivar BRS 216 após processos de irradiação e germinação, individualmente e associados. Inicialmente os grãos foram irradiados com 60Cobalto, nas doses de 0,025; 0,075 e 0,150kGy e logo em seguida germinados nos tempos de 48 e 72 horas. Para realização das análises propostas, as amostras foram congeladas e liofilizadas. As análises químicas realizadas foram: composição centesimal e mineral, digestibilidade de proteína in vitro, fatores antinutricionais, fenólicos totais, clorofila, carotenóides, vitaminas do complexo B (B1, B2 e B6) e capacidade antioxidante (ABTS e DPPH). Os aspectos sensoriais foram determinados aplicando-se método de aceitação e intenção de compra. Os resultados indicaram reduções nos teores de taninos, ácido fítico, inibidores de tripsina e hemaglutinina com o processo de germinção. Em decorrência das reduções nos teores dos fatores antinutricionais, notou-se aumento no conteúdo de fósfoto (P) e na digestibilidade de proteína. Maiores teores de vitaminas do complexo B (B1, B2 e B6) também foram observados após 48 e 72 horas de germinação. A disponibilidade dos minerais Ca, Fe, Zn e Mg não apresentaram alterações satisfatórias com o processo de germinação, contradizendo aos resultados encontrados na literatura. Os teores de fenólicos totais apresentaram aumento estatisticamente significativo após 72horas de germinação. A capacidade antioxidante da soja determinada pelo método ABTS+ apresentou valores superiores ao encontrado pelo método de DPPH. Alta correlação foi observado entre o método DPPH e o teor de fenólicos. Foi observado também aumento progressivo e significativo nos teores de clorofila e carotenóides durante a germinação dos grãos, o que evidencia, após realização do teste de Pearson, correlação alta e positiva entre a síntese desses componentes e processo germinativo. O processo de germinação resultou também no aumento estatisticamente significativo nos teores de umidade, pequenas alterações, porém estatisticamente semelhante ao grão controle nos teores de lipídeos e proteínas e diminuições nos teores de cinzas e carboidratos. Para todas as análises químicas realizadas, o processo de irradiação nas diferentes doses utilizadas não influenciou nas concentrações dos compostos analisados. Em relação à análise sensorial, foi observada maior rejeição nas sojas germinadas há 72 horas quando comparados ao tempo de 48 horas. Mesmo assim, apresentou rejeição inferior a 50%, o que pode ser utilizado na produção de brotos, como forma de complemento nutricional na dieta alimentar. Portanto conclui-se que as sojas germinadas, contribuem uma dieta de alta qualidade devendo ser estimulado o aumento do seu consumo na dieta brasileira. / Soybean (Gycine max (L.) Merrill) is an important legume for human diets due its potential health benefits. Because of the increasing stimulus to soybean consumption, mainly due to its several bioactive compounds, some processing methods have been studied as a way to know changes that occur in these compounds during the processes. Thus, this study aimed to analyze changes in the sensory and nutritional composition of soybean cultivar BRS 216 after irradiation and germination processes, isolated and associated. Initially, the grains were irradiated with Cobalt 60 at doses of 0.025, 0.075 and 0.150 kGy and afterwards, they were germinated at 48 and 72 hours. The samples were frozen and lyophilized to perform the proposed analyses. Chemical analyses were conducted on mineral and chemical composition, in vitro protein digestibility, antinutritional factors, total phenolics, chlorophyll, carotenoids, vitamins B (B1, B2 and B6) and antioxidant capacity (ABTS and DPPH). The sensory aspects were determined by applying the method of acceptance and purchase intent. The results showed reductions in levels of tannins, phytic acid, trypsin inhibitors and hemagglutinin with the germination process. As a result of reductions in levels of anti-nutritional factors, it was observed an increase in the phosphorus content (P) and protein digestibility. Higher contents of vitamins B (B1, B2 and B6) were also observed after 48 and 72 hours of germination. The availability of the minerals Ca, Fe, Zn and Mg showed no satisfactory changes to the germination process, contradicting the findings in the literature. The contents of phenolic compounds showed a statistically significant increase after 72 hours of germination. The antioxidant capacity of soybean determined by the ABTS+ method presented higher values than in the DPPH method. High correlation was observed between the DPPH method and phenolic content. It was also observed a significant and progressive increase in contents of chlorophyll and carotenoids during the grain germination, which suggests high positive correlation between the synthesis of these components and the germination process, after running the Pearson test. The germination process also resulted in a statistically significant increase in moisture content, small changes, however statistically similar to the control grain in contents of lipids and proteins and decreases in contents of ash and carbohydrates. In all the chemical analyses, the irradiation process at different doses did not influence the concentrations of the compounds analyzed. As for the sensory analysis, rejection of soybeans germinated for 72 hours was greater when compared to 48 hours. Still, this rejection was 50% lower, which can be used in the production of sprouts, as a means of nutritional supplement in the diet. Therefore, it is concluded that the germinated soybean contribute to a high quality diet and its consumption in the Brazilian diet should be encouraged.
77

Avaliação da atividade de sementes de mostarda (Brassica alba, L.). I - Identificação dos principais compostos responsáveis pela inibição da oxidação / Antioxidant activity evaluation of mustard seeds (Brassica alba L.). I identification of main compounds responsible for the oxidation inhibition

Moreira, Ana Vládia Bandeira 05 April 1999 (has links)
Um dos principais problemas na conservação dos alimentos é a ocorrência de processos oxidativos. A oxidação dos alimentos se dá, principalmente, entre os lípides que os compõem. O processo oxidativo induz à formação de substâncias que alteram as características sensoriais e nutricionais do alimento. Em estágios mais avançados a oxidação dos alimentos forma compostos que são prejudiciais ao organismo animal. Entre as maneiras de se prevenir o processo oxidativo, destaca-se o emprego de antioxidantes. Estes, frequentemente, são substâncias sintéticas. Antioxidantes sintéticos são compostos fenólicos e a eles são atribuídas algumas particularidades indesejáveis, pois os mesmos podem interferir em alguns processos fisiológicos do organismo animal. Com a perspectiva de substituição dos antioxidantes sintéticos, por substâncias naturais, diversos estudos têm sido realizados com os vegetais, usando a extração e identificação de compostos com atividade antioxidante. Tendo em vista que os vegetais, das espécies de Brassieca, apresentam elevadas concentrações de compostos fenólicos, este estudo teve por objetivo a detecção da presença da atividade antioxidante em diferentes extratos obtidos a partir de sementes de mostarda (Brassiea alba, L.), onde o extrato aquoso foi apresentou melhor atividade antioxidante com 68,1% de inibição da oxidação. Em uma segunda etapa foi realizada a identificação dos ácidos fenólicos nas sementes de mostarda, aos quais se atribuiu a capacidade inibidora da oxidação. Foram identificados, através da cromatografia em fase gasosa, os seguintes ácidos fenólicos: salicílico, trans cinâmico, &#961;-hidroxibenzóico, vanílico, gentíssico, quínico, &#961;-cumárico, ferúlico, caféico, cis e trans sináptico e a catequina. O ácido &#961;-hidroxibenóico foi o que apresentou maior em maior quantidade e com bom potencial de inibição da oxidação. Os resultados obtidos, demonstraram a existência de elevada atividade antioxidante nas sementes de mostarda e infere-se, que no futuro, essa especiaria ou alguns de seus compostos isolados poderão vir a ser utilizados como antioxidantes no processamento de alimentos. / The oxidative process ia a problem in food conservation. It can occure frequently among the lipids and fatty acids. Substances produced by the oxidative process promote modification in sensorial and nutritional food characteristics. During the oxidative process these substances may form compounds deleterious to animal organism. Synthetic antioxidants are substances often used for the inhibition of the oxidation process. These substances are phenolic compounds and they can induce some toxic effects. Many studies with vegetables have been done to identify natural antioxidants compounds by extracting and isolating these substances to replace them with sintetic antioxidants. Once that Brassica species have high amounts of phenolic acids, the studies were focused on the phenolic acids evaluation with antioxidant activity in the extracts of mustard seeds (Brassiea alba, L.), where the aqueous extract had the best antioxidant activity with 68,1% of oxidation inhibition. The second step was identify the phenolic acids in mustard seeds that have the capacity to inhibit oxidation. The phenolic acids found were: salycilic, trans cinnamic, &#961;-hydroxybenzoic, vanilic, gentissic, quinic, &#961;-coumaric, ferulic, caffeic, cis and trans sinapic and catequin. The &#961;-hidroxybenzoic acid was identify with a high composition and with a good potential of oxidation inhibition. The results obtained showed high antioxidant activity in mustard seeds. In the future this spice and its phenolic compounds might be used as antioxidants in food.
78

Avaliação de equivalência substancial e potencial de alergenicidade de cultivares de soja tolerantes ao herbicida glifosato / Evaluation of substantial equivalence and potential of allergenic reactions of soybean cultivars tolerant to the glyphosate herbicide

Giora, Cintia Bezuti 25 June 2009 (has links)
Os parâmetros de avaliação de segurança de alimentos geneticamente modificados fundamentam-se na comparação de equivalência substancial entre as variedades e pela inocuidade de proteínas da planta GM com as proteínas encontradas nas plantas convencionais. O objetivo deste trabalho foi avaliar a segurança alimentar de três cultivares de sojas geneticamente modificadas para tolerarem o herbicida glifosato através da determinação da equivalência substancial e do potencial alergênico das mesmas quando comparadas às suas respectivas parentais isogênicas. Seis amostras de soja foram analisadas, sendo três convencionais parentais e três GM, referentes ao cultivo de 2004-2005, em Goiás. Para a composição química foram realizadas análises em triplicata de proteínas, lipídeos, umidade, minerais e fibra alimentar. Análises complementares para determinação de aminoácidos, ácidos graxos, isoflavonas e ácido fítico também foram realizadas. O potencial de alergenicidade foi avaliado em extratos protéicos brutos de três cultivares convencionais e suas correspondentes GM. Os mesmos extratos protéicos foram fracionados para obter as globulinas 7S e 11S por precipitação e posterior purificação em coluna de bioafinidade Sepharose 4B. A glicoproteína 7S foi obtida a partir da eluição com tampão contendo -D-mannopyranoside. A resistência à proteólise foi realizada a partir de dois fluidos gástricos simulados com pepsina nas proporções 2,5:100 e 13:1 de enzima/substrato. As amostras foram submetidas à eletroforese dissociante para se estimar a resistência à ação da pepsina em função da concentração da enzima e do tempo de incubação. Extratos brutos protéicos e frações hidrolisadas foram testados contra soros de pacientes comprovadamente alérgicos e não alérgicos à soja nas concentrações de 1/20 em ensaios imunoquímicos do tipo ELISA e 1/10 em ensaios do tipo Western blotting. Os resultados da composição básica de nutrientes mostraram dispersões normais esperadas entre as amostras de mesma origem, com tendências de níveis superiores de proteínas de 9 a 16% nas amostras GM. As análises de fibras insolúveis e isoflavonas revelaram valores de decréscimo das amostras GMs em relação aos teores das variedades convencionais, contrastando com o acréscimo de valores de ácido fítico nas mesmas cultivares. Quanto à proteólise, foi possível observar estabilidade de bandas protéicas com pesos moleculares em torno de 50 e 18 KDa nos extratos brutos, 10 KDa nos extratos de 11S e 50 KDa nos extratos de 7S, em geral similares entre as parentais isogênicas e GMs. Os testes de reatividade dos soros de pacientes alérgicos e não alérgicos em extratos brutos protéicos das cultivares GM demonstraram reatividade similar quando comparados às suas respectivas parentais isogênicas. Com a observação dos resultados pode-se concluir que as diferenças significativas apresentadas pelas amostras GM não as tornam inseguras para o consumo humano e animal. Da mesma forma que não foram observadas alterações na alergenicidade das amostras GM em relação às amostras parentais isogênicas por apresentarem perfis semelhantes de proteólise frente à pepsina e aos testes imunológicos contra soros de pacientes alérgicos. / The parameters of security evaluation of genetically modified foods are based on the substantial equivalence among varieties and the innocuity of GM vegetal proteins compared with conventional vegetal proteins. The aim of this work was to evaluate the food safety of three genetically modified soybean cultivars to tolerate glyphosate herbicide through substantial equivalence determination and allergenic potential when compared to their respective isogenic parental. Six samples analyzed were three parental soybean (conventional) and the others GM, regarding to the crop of 2004-2005, grown in Goiás state. The chemical composition was performed in triplicate and the content of moisture, minerals, proteins, lipids and fiber were determined. Additional compounds like aminoacids, fatty acids, isoflavons and phytates were analyzed. The potential of allergenic reactions was evaluated in crude protein extracts of three conventional and their corresponding GM cultivars. The same protein extracts were fractionated to obtain 7S and 11S globulins by precipitation and posterior purification on Sepharose 4B bioaffinity column. The 7S glycoprotein was obtained by elution with -D-mannopyranoside buffer. The resistance to proteolysis was performed by two simulated gastric fluids with pepsin at the proportions 2,5:100 and 13:1 enzyme/substrate. The samples were run by SDS electrophoresis to estimate the resistance to pepsin action according to enzyme concentration and incubation time. Crude protein extracts and hydrolyzed fractions were tested against serum of allergic and non-allergic patients through ELISA immunochemistry essays at concentrations of 1/20 and Western blotting, 1/10. The results of chemical composition of nutrients showed an expected normal dispersion among samples from the same origin, with tendencies for superior levels of proteins from 9 to 16% by GM samples. The analyses of insoluble fibers and isoflavons revealed decreased values at GM samples regarding to the contents on conventional varieties, contrasting with the increase of the phytic acid values in the same cultivars. After the proteolysis, some protein bands remained apparently stable, that correspond to molecular weights around 50 and 18 KDa for crude extracts, 10 KDa for 11S extracts and 50 KDa for 7S extracts. The undigested proteins are similar in both set of samples, the parental isogenic and GM soybeans. Immuno-reactivity of proteins from crude extracts with serum from allergic and non allergic patients were also similar for isogenic and GM cultivars. These results allow us to state that the significant differences observed in the composition of GM samples will neither affect the nutrient levels nor the safety of their consumption as food or feed. As well as there were no observed changes at the potential allergenicity of GM samples regarding to parental isogenic samples by exhibit similar proteolysis profile related to pepsin and immunological essays against allergic patient serums.
79

Bioactive food ingredient acceptance of health conscious consumers in two adjoining subcouncils of the City of Cape Town

OConnor, Karen January 2010 (has links)
Thesis (MTech (Consumer Science)--Cape Peninsula University of Technology, 2010 / Globally, and in South Africa, consumers have become concerned about living healthier lifestyles as well as acquiring an understanding of health and using self-medication as disease preventative measures. This has resulted in an expanding consumer interest in functional foods and the non-nutrient bioactive ingredients in foods that support health. The aim of this study therefore was to determine: (i) the level of awareness, knowledge and understanding (i.e. acceptance) of functional foods and a number of bioactive food ingredients of health conscious consumers in two adjoining subcouncils of the City of Cape Town and (ii) the demographic, health and lifestyle characteristics and other socioenvironmental influences affecting their acceptance of bioactive ingredients in functional foods to describe the consumer market for functional foods and the bioactive food ingredients investigated. For the purpose of this study two groups of respondents representing the health conscious consumer were purposefully sampled. One hundred and thirty nine respondents representing the health conscious market, which includes gym subscribers and dietary supplement users, anonymously and voluntarily participated (67% response rate) from the two subcouncils, De Grendal and Blaauwberg, representing a higher economically active segment of the City of Cape Town Metropolitan Municipality.
80

Caracterização e síntese dos inibidores de &#945;-amilase do feijão (Phaseolus vulgaris) / Characterization and synthesis of alpha amylase inhibitor from beans (Phaseolus vulgaris)

Iguti, Antonia Miwa 30 April 1993 (has links)
Inibidores de alfa amilase de feijão (Phaseolus vulgaris) foram caracterizados. O inibidor da variedade Jalo apresentou peso molecular de 50kDa (por filtração em gel), ponto isoelétrico de 4,75 e 9,6% de carboidratos. O inibidor da variedade Argentino apresentou peso molecular de 48kDa, ponto isoelétrico de 4,90 e 7,6% de carboidratos. Ambos inibidores apresentaram pH ótimo de interação com alfa amilase pancreática de porco de 5,0 e, a pH 6,9, a complexação com a mesma enzima se deu na proporção de 1:1. Esses resultados, mais a composição de aminoácidos, indicaram que as características desses inibidores são semelhantes às de outros já purificados de diferentes variedades de feijão. As principais diferenças entre o IA do Jalo e do Argentino, foram observadas através de termogramas, do teor de carboidratos e dos ensaios imunológicos. Além disso, são sintetizados entre 20 e 30 dias após a floração, sendo que o processo ocorre simultaneamente ao da síntese das proteínas de reserva do grão. Inibidores purificados das variedades Jalo, Argentino e Rico 23, em diferentes fases do desenvolvimento, indicaram ausência de grandes alterações estruturais durante esse processo. / &#945;-amylase inhibitors of bean (Phaseolus vulgaris) were characterized. The amylase inhibitor from Jalo had molecular weight of 50 kDa (by gel filtration), an isoeletric point of 4.75 and a carbohydrate content of 9.6%. Argentino presented molecular weight of 48 kDa, an isoeletric point of 4.90 and a carbohydrate content of 7.6%. The optimum pH for inhibition of porcine pancreatic &#945;-amylase for both inhibitors was about 5.0 and they formed 1:1 stoichiometric complex. These results and the amino acid composition indicated that these inhibitors have characteristics similar to others already purified from beans. They were synthesized between 20 and 30 days after anthesis and this process occurred simultaneously to the storage proteins synthesis. Purified inhibitors from seeds in different phases of development indicated lack of great structural changes during this process.

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