Cross-linking in soy proteins is hypothesised to have an impact on the texture of tofu. In vitro incubation showed soy proteins and its two fractions, glycinin and β-conglycinin, were cross-linked using glutaraldehyde, formaldehyde, glyceraldehyde and transglutaminase (TGA). Increasing concentration of these carbonyl compounds and TGA, and temperature of the carbonyl compounds treatment, increased the reactivity of cross-linking. Glutaraldehyde was the most reactive in forming aggregated proteins, followed by formaldehyde and glyceraldehyde. Both carbonyl moieties of glutaraldehyde are believed to be essential for the rapid cross-linking reaction. In the unfractionated soy proteins, β-conglycinin had a higher reactivity than glycinin. In in vitro incubation using TGA, soy proteins served as good substrates for TGA, in which β-conglycinin was more susceptible to TGA than glycinin in the unfractionated soy proteins. The addition of TGA, and 1 and 2 mM glutaraldehyde prior to soymilk boiling in situ resulted in a small number of cross-linked proteins, which correspond to an increase in fracture force. The addition of glutaraldehyde after soymilk boiling resulted in a slight decrease in fracture force compared to the control. At higher concentrations of glutaraldehyde (15 and 30 mM), soy proteins were mostly cross-linked, regardless of addition before or after soymilk boiling. Highly cross-linked proteins resulted in a significant decrease in the fracture force. For TGA treatment, the fracture force was increased with increasing TGA concentration from 1000 to 5000 ppm, added either before or after soymilk boiling. However, the TGA treatment showed only a small quantity of cross-linking. It is hypothesised that TGA hydrolysed glutamine of proteins to glutamate and changed the functional properties of proteins. Upon examination of the microstructure, it was found that the TGA treatment resulted in a fine-stranded network, compact structure and less porosity. These characteristics resulted in a higher fracture force. In contrast, in the glutaraldehyde treatment, the network consisted of a higher porosity, loose network and diffuse structure, which gave lower fracture force. Thus, it appears that substrate modification to the structure of the soy proteins may have a greater impact than the number of cross-links. These findings are likely to have implications for production of soy products with a wide range of textures by manipulating the soy protein properties.

Cross-linking in soy proteins is hypothesised to have an impact on the texture of tofu. In vitro incubation showed soy proteins and its two fractions, glycinin and β-conglycinin, were cross-linked using glutaraldehyde, formaldehyde, glyceraldehyde and transglutaminase (TGA). Increasing concentration of these carbonyl compounds and TGA, and temperature of the carbonyl compounds treatment, increased the reactivity of cross-linking. Glutaraldehyde was the most reactive in forming aggregated proteins, followed by formaldehyde and glyceraldehyde. Both carbonyl moieties of glutaraldehyde are believed to be essential for the rapid cross-linking reaction. In the unfractionated soy proteins, β-conglycinin had a higher reactivity than glycinin. In in vitro incubation using TGA, soy proteins served as good substrates for TGA, in which β-conglycinin was more susceptible to TGA than glycinin in the unfractionated soy proteins. The addition of TGA, and 1 and 2 mM glutaraldehyde prior to soymilk boiling in situ resulted in a small number of cross-linked proteins, which correspond to an increase in fracture force. The addition of glutaraldehyde after soymilk boiling resulted in a slight decrease in fracture force compared to the control. At higher concentrations of glutaraldehyde (15 and 30 mM), soy proteins were mostly cross-linked, regardless of addition before or after soymilk boiling. Highly cross-linked proteins resulted in a significant decrease in the fracture force. For TGA treatment, the fracture force was increased with increasing TGA concentration from 1000 to 5000 ppm, added either before or after soymilk boiling. However, the TGA treatment showed only a small quantity of cross-linking. It is hypothesised that TGA hydrolysed glutamine of proteins to glutamate and changed the functional properties of proteins. Upon examination of the microstructure, it was found that the TGA treatment resulted in a fine-stranded network, compact structure and less porosity. These characteristics resulted in a higher fracture force. In contrast, in the glutaraldehyde treatment, the network consisted of a higher porosity, loose network and diffuse structure, which gave lower fracture force. Thus, it appears that substrate modification to the structure of the soy proteins may have a greater impact than the number of cross-links. These findings are likely to have implications for production of soy products with a wide range of textures by manipulating the soy protein properties.

Made available in DSpace on 2014-06-11T19:23:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-29Bitstream added on 2014-06-13T19:29:46Z : No. of bitstreams: 1 fassini_pg_me_arafcf.pdf: 613112 bytes, checksum: f00daa1b71f5ee79d5673101f5d6e0e8 (MD5) / Universidade Estadual Paulista (UNESP) / A globulina 11S (glicinina) é a proteína predominante da soja e tem sido extensivamente caracterizada. Além das suas propriedades nutricionais, há evidências de sua participação na redução das concentrações lipídicas do soro. Por outro lado, o fármaco rosuvastatina tem suas ações demonstradas no metabolismo lipídico, por reduzir a fração LDL-colesterol, bloqueando a chave do processo de produção de colesterol hepático. Embora a eficiência do medicamento seja comprovada, é importante considerar a alimentação como uma possível ação somatória, tendo em vista os graves problemas ocasionados pelas alterações lipídicas no organismo. À vista do exposto, a presente pesquisa teve por objetivo estudar o efeito da glicinina isolada da soja em comparação ao fármaco rosuvastatina em animais submetidos à dieta hipercolesterolêmica. Foram elaboradas duas dietas, uma padrão, contendo caseína como proteína (AIN-93M), e outra hipercolesterolêmica, composta pela dieta padrão adicionada de 1% de colesterol e 0.5% de ácido cólico. A proteína glicinina de soja (300 mg/kg de peso corporal) e o fármaco rosuvastatina (10 mg/Kg de peso corporal), ambos solubilizados em solução salina, foram administrados por gavagem. Foram utilizados ratos machos Wistar mantidos em gaiolas individuais sob condições adequadas. Os animais foram separados em cinco grupos (n = 9): 1) grupo padrão (STD) recebeu a dieta padrão; 2) grupo hipercolesterolêmico (HC) recebeu apenas a dieta hipercolesterolêmica; 3) grupo (HC+11S) recebeu a dieta e a proteína glicinina da soja; 4) grupo (HC+ROS) recebeu a dieta e o fármaco; 5) grupo (HC+ROS+11S) recebeu a dieta, a proteína e o fármaco. Ao final de 28 dias os animais foram sacrificados e o sangue removido para análises bioquímicas de colesterol total (CT), HDL-colesterol (HDL-C) e triglicérides (TG) plasmático, CT e TG hepático... / The 11S globulin (glycinin) is the predominant protein of soybeans and has been extensively characterized. In addition to its nutritional properties there is evidence of its action in reducing serum lipid concentrations. Moreover, the drug rosuvastatin has demonstrated its effects on lipid metabolism, by reducing LDL cholesterol and blocking the key enzyme in the process of cholesterol production in the liver. Although the efficiency of the drug is proven, it is important to consider the sum of its action and that of food, in view of the serious problems caused by changes in body fat. In view of the foregoing, the aim of the present study was to investigate the effects of isolated soy glycinin, as compared to the drug rosuvastatin, in rats subjected to a hypercholesterolemic diet. Two diets were prepared, a standard diet, containing casein as protein (AIN-93M), and a hypercholesterolemic, consisting of the standard diet plus 1% cholesterol and 0.5% cholic acid. The glycinin (300 mg/kg body weight) and the rosuvastatin (10 mg/kg body weight), both dissolved in saline, were administered by gavage. Male Wistar rats were kept in individual cages under appropriate conditions. The animals were divided into five groups (n=9): 1) standard group (STD) received the standard diet; 2) hypercholesterolemic group (HC) received the hypercholesterolemic diet alone; 3) group HC+11S received the HC diet and the glycinin; 4) group HC+ROS received the HC diet and the drug; 5) group HC+ROS+11S received the HC diet, the protein and the drug. After 28 days, the animals were sacrificed and the blood removed for biochemical analysis of total plasma cholesterol (TC), HDL-cholesterol (HDL-C) and triglycerides (TG), and hepatic TC and TG. The results indicated that the experimental HC diet was able to induce hypercholesterolemia and that a single daily dose of the isolated protein was appropriate for a comparative... (Complete abstract click electronic access below)

Master of Science / Department of Grain Science and Industry / X. Susan Sun / Soybean protein modified with sodium bisulfite behaves like latex adhesives, with adhesive strength comparable to formaldehyde-based adhesives. β-conglycinin and glycinin are two major protein components of the adhesive system. The objective of this research was to investigate the effect of sodium bisulfite on the physicochemical, morphological, and adhesion properties of glycinin and β-conglycinin in order to better understand the function of glycinin and β-conglycinin in the formation of the soy latex adhesive. Sodium bisulfite broke the disulfide bonds that linked acidic and basic polypeptides of glycinin, and the reducing effect was enhanced with increasing sodium bisulfite concentration. Although cleavage of disulfide bonds was expected to destabilize proteins, the thermal stability of glycinin increased as the sodium bisulfite concentration increased. Sodium bisulfite modified glycinin had higher surface hydrophobicity, which facilitated hydrophobic interations between molecules and aggregation of glycinin. The balance between hydrophobic interactions and electrostatic forces makes glycinin form unique chain-like structures. Adhesive performance of glycinin dropped significantly at lower sodium bisulfite concentration and then increased as sodium bisulfite concentration increased up to 24 g/L. Excess sodium bisulfite was detrimental to adhesive strength and water resistance. High-molecular-weight aggregates were observed in unmodified β-conglycinin, but these aggregates were dissociated by sodium bisulfite treatment. Similar to glycinin, the thermal stability of β-conglycinin was improved by the modification. However, the denaturation enthalpy of β-conglycinin decreased significantly at high level of sodium bisulfite (36 g/L). The turbidity at pH 4.8 also dropped extensively at the concentration of 36 g/L. The contact angle of β-conglycinin reached its minimum at 6 g/L sodium bisulfite on cherry wood and 24 g/L on glass. Morphology study proved that sodium bisulfite modification made the β-conglycinin solution more dispersed. At pH 9.5, water resistance of β-conglycinin was improved to a small extent by 6 g/L sodium bisulfite. At pH 4.8, adhesive performance was enhanced by 3 g/L and 6 g/L sodium bisulfite. High level of sodium bisulfite at 36 g/L reduced the adhesive performance of β-conglycinin drastically.

Orientador: Aureluce Demonte / Banca: Valdir Augusto Neves / Banca: Olga Luisa Tavano / Resumo: A globulina 11S (glicinina) é a proteína predominante da soja e tem sido extensivamente caracterizada. Além das suas propriedades nutricionais, há evidências de sua participação na redução das concentrações lipídicas do soro. Por outro lado, o fármaco rosuvastatina tem suas ações demonstradas no metabolismo lipídico, por reduzir a fração LDL-colesterol, bloqueando a chave do processo de produção de colesterol hepático. Embora a eficiência do medicamento seja comprovada, é importante considerar a alimentação como uma possível ação somatória, tendo em vista os graves problemas ocasionados pelas alterações lipídicas no organismo. À vista do exposto, a presente pesquisa teve por objetivo estudar o efeito da glicinina isolada da soja em comparação ao fármaco rosuvastatina em animais submetidos à dieta hipercolesterolêmica. Foram elaboradas duas dietas, uma padrão, contendo caseína como proteína (AIN-93M), e outra hipercolesterolêmica, composta pela dieta padrão adicionada de 1% de colesterol e 0.5% de ácido cólico. A proteína glicinina de soja (300 mg/kg de peso corporal) e o fármaco rosuvastatina (10 mg/Kg de peso corporal), ambos solubilizados em solução salina, foram administrados por gavagem. Foram utilizados ratos machos Wistar mantidos em gaiolas individuais sob condições adequadas. Os animais foram separados em cinco grupos (n = 9): 1) grupo padrão (STD) recebeu a dieta padrão; 2) grupo hipercolesterolêmico (HC) recebeu apenas a dieta hipercolesterolêmica; 3) grupo (HC+11S) recebeu a dieta e a proteína glicinina da soja; 4) grupo (HC+ROS) recebeu a dieta e o fármaco; 5) grupo (HC+ROS+11S) recebeu a dieta, a proteína e o fármaco. Ao final de 28 dias os animais foram sacrificados e o sangue removido para análises bioquímicas de colesterol total (CT), HDL-colesterol (HDL-C) e triglicérides (TG) plasmático, CT e TG hepático... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The 11S globulin (glycinin) is the predominant protein of soybeans and has been extensively characterized. In addition to its nutritional properties there is evidence of its action in reducing serum lipid concentrations. Moreover, the drug rosuvastatin has demonstrated its effects on lipid metabolism, by reducing LDL cholesterol and blocking the key enzyme in the process of cholesterol production in the liver. Although the efficiency of the drug is proven, it is important to consider the sum of its action and that of food, in view of the serious problems caused by changes in body fat. In view of the foregoing, the aim of the present study was to investigate the effects of isolated soy glycinin, as compared to the drug rosuvastatin, in rats subjected to a hypercholesterolemic diet. Two diets were prepared, a standard diet, containing casein as protein (AIN-93M), and a hypercholesterolemic, consisting of the standard diet plus 1% cholesterol and 0.5% cholic acid. The glycinin (300 mg/kg body weight) and the rosuvastatin (10 mg/kg body weight), both dissolved in saline, were administered by gavage. Male Wistar rats were kept in individual cages under appropriate conditions. The animals were divided into five groups (n=9): 1) standard group (STD) received the standard diet; 2) hypercholesterolemic group (HC) received the hypercholesterolemic diet alone; 3) group HC+11S received the HC diet and the glycinin; 4) group HC+ROS received the HC diet and the drug; 5) group HC+ROS+11S received the HC diet, the protein and the drug. After 28 days, the animals were sacrificed and the blood removed for biochemical analysis of total plasma cholesterol (TC), HDL-cholesterol (HDL-C) and triglycerides (TG), and hepatic TC and TG. The results indicated that the experimental HC diet was able to induce hypercholesterolemia and that a single daily dose of the isolated protein was appropriate for a comparative... (Complete abstract click electronic access below) / Mestre

Orientador: Rosiane Lopes da Cunha / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-19T15:27:22Z (GMT). No. of bitstreams: 1 Tarone_AdrianaGadioli_M.pdf: 2280055 bytes, checksum: 80f679038904a40c6485d29994fed7ce (MD5) Previous issue date: 2012 / Resumo: Dietas a base de vegetais e suas proteínas têm se tornado cada vez mais populares visando saúde e bem-estar. Dentre as proteínas vegetais, a de soja é a mais utilizada como ingrediente na indústria de alimentos, atuando inclusive como estabilizante de emulsões e agente gelificante. As globulinas 7S (ß ¿ conglicinina) e 11S (glicinina) são as principais frações protéicas da soja, sendo que a primeira possui boa capacidade emulsificante e a segunda tem alto poder gelificante. Em função de condições de processo, como temperatura e pressão, as propriedades funcionais das frações protéicas de soja podem ser modificadas, dado que estas possuem diferente susceptibilidade ao calor e cisalhamento. Assim, este trabalho teve como objetivo estudar a capacidade emulsificante e gelificante das frações 7S e 11S da proteína de soja liofilizadas ou secas em "spray dryer¿ a 120, 150 ou 180ºC. Estas foram caracterizadas por eletroforese em gel de poliacrilamida, potencial zeta, isotermas de sorção, microscopia ótica, cor, distribuição de tamanho de partícula, densidades real e aparente e calorimetria diferencial de varredura. Quanto à cor, as amostras secas em "spray dryer¿ foram as mais claras, principalmente as secas em maior temperatura, que também apresentaram as menores umidade e densidade aparente. A capacidade gelificante das frações protéicas foram estudadas em pH 3 e 7 a partir de ensaios oscilatórios, propriedades mecânicas e capacidade de retenção de água. Os ensaios reológicos oscilatórios mostraram que o comportamento elástico predominou sobre o viscoso nas amostras em pH 3, ocorrendo o inverso em pH 7. Este comportamento foi mais acentuado na fração rica em 11S que na rica em 7S, devido à sua capacidade de formar géis mais fortes. O aumento da temperatura de secagem levou a um deslocamento do ponto de gel a temperaturas mais elevadas, porém diminuiu o módulo de elasticidade ou a capacidade de gelificação. Estes resultados foram confirmados pelas propriedades mecânicas, pois a maiores temperaturas de secagem, os géis eram mais frágeis e quebradiços, especialmente quando formados em pH 7. Emulsões O/A foram preparadas pela mistura de óleo de soja com uma dispersão aquosa contendo uma das frações protéicas em pH 3 e 7. As emulsões obtidas foram avaliadas com relação à estabilidade a cremeação, distribuição do tamanho de gota, medidas reológicas e quantidade de proteínas na fase superior. As emulsões estabilizadas pela fração 7S foram mais estáveis em pH 7, enquanto que a 11S se mostrou mais estável em pH 3. O aumento da temperatura de secagem aumentou o poder emulsificante das frações 7S e 11S em pH 7 e 3, respectivamente. Portanto, a partir dos resultados obtidos foi possível verificar que, dependendo da condição de secagem utilizada, podem-se obter ingredientes com propriedades tecnológicas que sejam mais adequadas ao produto em que será aplicado e às suas características de qualidade / Abstract: Diets based on vegetables and their proteins have become increasingly popular for health and welfare. Among the vegetable proteins, the soy is the most widely used as an ingredient in the food industry, including acting as emulsion stabilizers and gelling agents. The 7S (ß - conglycinin) and 11S (glycinin) globulins are the main soy protein fractions, with the former having good emulsifying capacity and the second, a high gelling power. Due to the process conditions, such as temperature and pressure, the functional properties of soy protein fractions can be modified, since they have different susceptibility to heat and shear. Thus, the main objective of this study is to evaluate the emulsifying and gelling capacity of the soy protein fractions (7S and 11S) lyophilized and spray-dried at 120, 150 or 180 ° C. These were characterized by polyacrylamide gel electrophoresis, zeta potential, sorption isotherms, optical microscopy, color, particle size distribution, real and apparent densities and differential scanning calorimetry. The spray-dried samples were clearer, especially the ones dried at higher temperatures, which also had lower moisture content and bulk density. The gelling ability of the protein fractions were studied at pH 3 and 7, based on the oscillatory tests, mechanical properties and water holding capacity. The oscillatory rheological tests showed that the elastic behavior predominated upon the viscous for the pH 3 samples, occurring the opposite for the pH 7. This behavior was more accentuated for the 11S-rich fractions than for the 7S -rich, due to their ability to form strong gels. The drying temperature increase led to a displacement of the gelling point to higher temperatures, but decreased the elasticity module or the gelling ability. These results were confirmed by the mechanical properties, because when exposed to higher drying temperatures, the gels were more brittle and fragile, especially when prepared at pH 7. O/A emulsions were prepared by mixing soy oil with an aqueous dispersion containing one of protein fractions at pH 3 and 7. The obtained emulsions were evaluated for creaming stability, droplet size distribution, rheological measurements and amount of protein at the top phase. Emulsions stabilized by 7S fraction were more stable at pH 7, while the 11S were more stable at pH 3. The drying temperature increase raised the emulsifying power of 7S and 11S fractions at pH 7 and 3, respectively. Therefore, based on the results, was identified that depending on the drying condition used, it is possible to obtain ingredients with technology that are more appropriate to the product and their quality characteristics / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

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.

Tofu is a plant based product made from soybeans, water and a coagulant. The coagulant together with heating enables the formation of a soy curd (tofu). The proteins that dominates in soybeans are β-conglycinin (7S) and glycinin (11S). The composition of the proteins differs between soybean cultivars, which also affects the formation of the tofu. The object in this study was to evaluate the vitamin C content and the stability of vitamin C during processing and storage in an ecological tofu-product after enrichment of Sea Buckthorn to increase the vitamin content. Furthermore, the use of germinated soy beans instead of soaked soybeans in the production of tofu was evaluated. When Sea Buckthorn was added to the soymilk it resulted in a decrease in pH from 6.3 to 5.5, which affected the formation of the soy curd negatively as the optimal pH is between 6.0 and 6.5. By adding alkali to reach pH 6.3 it was possible to achieve a soy curd when Sea Buckthorn powder was added. Sea Buckthorn increased the vitamin C content in the product to 32 mg/250 g but only 10% (about 3 mg) remained after four weeks storage. The loss of vitamin C was large in both processing and storage of the tofu. An additional loss of 7- 14% was detected during 10 minutes heating (60°C). Germination of soybeans did neither affect the amount of protein, nor the vitamin C content in tofu. To produce a tofu with more than 15% of RDI for vitamin C in one serving (100 g) the amount berry powder to be added in the production of 250 g tofu must not be less than 31 g (400 mg vitamin C), based on losses up to 90-95% during the process and storage. Hence the huge amount of berry powder that must be added, other ways to decrease the degradation of vitamin C is necessary to be investigated.

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.