Poucos trabalhos foram publicados envolvendo a biossíntese do AA em plantas desde sua descoberta em 1928. O mecanismo de biossíntese era um mistério até 1998 quando Wheeler, Jones e Smirnoff demonstraram que a L-galactose é um precursor chave desta importante vitamina. Utilizando-se açúcares marcados e frios pudemos confirmar o mecanismo Smirnoff-Wheeler de biossíntese do AA. Neste trabalho nós apresentamos os resultados alcançados usando alguns supostos precursores e alguns frutos como o morango, a goiaba e o mamão papaya, e alguns legumes como o brócolis, alguns deles ricos em AA. As técnicas de HPLC e espectrofometria UVNIS foram utilizadas na determinação do AA. Os vegetais foram mantidos em soluções dos precursores frios por 24 horas e então analisados quanto ao teor de AA. Os resultados do uso de compostos marcados foi analisado utilizando-se a cintilografia líquida (LSC). Os açúcares extraídos do brócolis, do mamão papaya e da goiaba que foram infiltrados com D-[U-14C] manose, L-[1-14C] galactose e D-[U-14C] glucose-1-P mostraram diferentes padrões de distribuição entre os açúcares envolvidos no mecanismo Smirnoff-Wheeler de biossíntese do AA. Em folhas de goiabeira encontramos altos teores de ácido desidroascórbico e pequena quantidade de AA, diferentemente do conteúdo de AA nos frutos. Nossos resultados confirmaram que a L-galactono-1 ,4-lactona é um precursor bastante eficiente do AA em frutos e proveram algumas evidências do envolvimento da 0- manose no mecanismo de biossíntese do AA em plantas. / Since the first isolation of the Ascorbic Acid (AA) in 1928, a few papers have been published leading with the determination the AA biosynthetic pathway in plants. This pathway was a mystery until recently when in 1998 Wheeler, Jones and Smirnoff demonstrated that L-galactose is a key precursor of this important vitamin. Using radiolabeled and non-radiolabeled sugars we were capable of giving support to the Smirnoff-Wheeler pathway of AA biosynthesis. In this work we present the results reached using some putative precursors and some fruits and vegetables as strawberry, guava, papaya and broccoli some of them very rich in AA. The techniques used for the AA analysis included UVNIS spectrophotometry and HPLC methods. The fruits and vegetables were maintained in the solution of the non-radiolabeled precursors for 24 hours and then analyzed for the AA content. The results of the use of radiolabeled precursors were analyzed using liquid scintillation (LSC). The sugars extracted from broccoli , papaya and guava, that were supplied with D-[U-14C] mannose, L-[1-14C] galactose and D-[U-14C] glucose-1-P dipotassium salt were analyzed using HPLC amperometric method and LSC showed different pattern of distribution between the sugars involved in the Smirnoff-Wheeler AA biosynthesis pathway. In guava leaves we found a high content of dehydroascorbic acid and low amount of AA, unlikely of the content of AA in the fruit. Our results confirmed that L -galactono-1 ,4-lactone is a very effective precursor of AA in fruits and provided some evidence of the involvement of D-mannose in AA biosynthesis in plants.

The aim of this work was to establish an analytical method for the simultaneous detection of five major opium alkaloids in poppy seeds by liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS). Once opium alkaloids were detected in poppy seeds, toxicological studies were carried out to establish if these compounds were detected in oral fluid (OF) of participants who ingested muffins containing poppy seeds. It is known that the ingestion of poppy seeds has caused positive opiate drug test results and much work has been reported in the scientific literature in the last 20 years. Researchers in the field have investigated alternatives to differentiate between heroin administration and that of other opiate drugs versus poppy seed ingestion. Most of the work which has been carried out relates to establishing illicit heroin use by examining biological matrices for the presence of acetylcodeine, thebaine, papaverine, noscapine and their associated metabolites. The research methodology consisted of establishing an LC-ESI-MS method for the simultaneous detection of five major opium alkaloids (morphine, codeine, thebaine, papaverine and noscapine). A deuterated internal standard (morphine-d3) was used for the quantitation of alkaloids in harvested poppy seeds and oral fluid samples. Due to technical difficulties, 3 LC-MS instruments were employed in this work. Electrospray ionisation was employed in all mass spectrometers but the analysers included an ion trap with octopole, a triple quadrupole and a hybrid quadrupole Orbitrap. Suitable extraction procedures were determined and harvested seeds purchased from a number of supermarkets were analysed for the presence of five alkaloid compounds using the LC-MS method. A small scale pilot study with 6 participants was carried out to establish if it was possible to fail an OF drug test for opiates after consuming poppy seed muffins. OF samples were collected post ingestion using Quantisal™ kits and the level of each of the opiates was monitored. The findings were that an LC-ESI-MS method was established for the simultaneous detection and quantitation of five major alkaloids. However, the method development process involved finding a solution to co-elution of morphine and codeine. The process also included resolving the issue of thebaine producing two peaks with identical mass spectra and separated by a difference of 6 minutes in retention time. Varying levels of alkaloids were identified in harvested poppy seeds: levels of these compounds differed considerably within and between batches of poppy seeds. These findings could be attributed to a number of factors, for example, where and how the plants were grown and methods of harvesting. Two poppy seed muffins were consumed as part of a toxicology study. Morphine was detected in the 5 minute sample in 5 out of the 6 participants with concentrations in OF of 0.5-0.8 ng mL-1; codeine was detected in 2 of the 6 participants at 1.5 and 2.6 ng mL-1. Thebaine, noscapine and papaverine were also detected in OF of a number of participants, which has not been previously reported in the literature. However, it should be noted that the values calculated are only estimated since the peak area ratios obtained were found to be less than the lowest concentration (10 ng mL-1) in the linear calibration range. In conclusion, an LC-ESI-MS method for the simultaneous detection and quantitation of five major opium alkaloids has been established and has been used to detect alkaloids in harvested poppy seeds and oral fluid samples. From a small pilot toxicology study, oral fluid results indicate that levels of morphine and codeine do not exceed the SAMSHA 40 ng mL-1 cut-off after ingestion of a realistic amount of poppy seeds contained within bakery products.

Poucos trabalhos foram publicados envolvendo a biossíntese do AA em plantas desde sua descoberta em 1928. O mecanismo de biossíntese era um mistério até 1998 quando Wheeler, Jones e Smirnoff demonstraram que a L-galactose é um precursor chave desta importante vitamina. Utilizando-se açúcares marcados e frios pudemos confirmar o mecanismo Smirnoff-Wheeler de biossíntese do AA. Neste trabalho nós apresentamos os resultados alcançados usando alguns supostos precursores e alguns frutos como o morango, a goiaba e o mamão papaya, e alguns legumes como o brócolis, alguns deles ricos em AA. As técnicas de HPLC e espectrofometria UVNIS foram utilizadas na determinação do AA. Os vegetais foram mantidos em soluções dos precursores frios por 24 horas e então analisados quanto ao teor de AA. Os resultados do uso de compostos marcados foi analisado utilizando-se a cintilografia líquida (LSC). Os açúcares extraídos do brócolis, do mamão papaya e da goiaba que foram infiltrados com D-[U-14C] manose, L-[1-14C] galactose e D-[U-14C] glucose-1-P mostraram diferentes padrões de distribuição entre os açúcares envolvidos no mecanismo Smirnoff-Wheeler de biossíntese do AA. Em folhas de goiabeira encontramos altos teores de ácido desidroascórbico e pequena quantidade de AA, diferentemente do conteúdo de AA nos frutos. Nossos resultados confirmaram que a L-galactono-1 ,4-lactona é um precursor bastante eficiente do AA em frutos e proveram algumas evidências do envolvimento da 0- manose no mecanismo de biossíntese do AA em plantas. / Since the first isolation of the Ascorbic Acid (AA) in 1928, a few papers have been published leading with the determination the AA biosynthetic pathway in plants. This pathway was a mystery until recently when in 1998 Wheeler, Jones and Smirnoff demonstrated that L-galactose is a key precursor of this important vitamin. Using radiolabeled and non-radiolabeled sugars we were capable of giving support to the Smirnoff-Wheeler pathway of AA biosynthesis. In this work we present the results reached using some putative precursors and some fruits and vegetables as strawberry, guava, papaya and broccoli some of them very rich in AA. The techniques used for the AA analysis included UVNIS spectrophotometry and HPLC methods. The fruits and vegetables were maintained in the solution of the non-radiolabeled precursors for 24 hours and then analyzed for the AA content. The results of the use of radiolabeled precursors were analyzed using liquid scintillation (LSC). The sugars extracted from broccoli , papaya and guava, that were supplied with D-[U-14C] mannose, L-[1-14C] galactose and D-[U-14C] glucose-1-P dipotassium salt were analyzed using HPLC amperometric method and LSC showed different pattern of distribution between the sugars involved in the Smirnoff-Wheeler AA biosynthesis pathway. In guava leaves we found a high content of dehydroascorbic acid and low amount of AA, unlikely of the content of AA in the fruit. Our results confirmed that L -galactono-1 ,4-lactone is a very effective precursor of AA in fruits and provided some evidence of the involvement of D-mannose in AA biosynthesis in plants.

A soja é uma leguminosa com alto valor nutricional, devido principalmente a seu alto conteúdo protéico. Dentre a cultura de grãos, a soja caracteriza-se como a mais importante do país, o que representa um incentivo ainda maior para o consumo desse alimento. Porém, este alimento ainda sofre restrições por parte dos consumidores ocidentais, devido, principalmente a seu odor e sabor característicos, conhecidos como beany flavor, que é proporcionado pela ação da enzima lipoxigenase. A ação catalítica exercida por esse tipo de isoenzima sobre ácidos graxos poliinsaturados, ácido linolênico e linoléico, dos grãos de soja é um dos principais fatores responsáveis pelo aparecimento dos compostos carbonílicos, os quais causam o sabor desagradável em grãos. Para melhorar as características organolépticas da soja, pesquisadores desenvolveram novas cultivares, sem a presença da lipoxigenase. O objetivo deste trabalho foi avaliar diferenças físicas, químicas e sensoriais entre as cultivares de soja com lipoxigenase e sem lipoxigenase (cultivar BRS 232 e BRS 257, da Embrapa, respectivamente) e analisar as possíveis alterações promovidas por diferentes doses de radiação (0, 4 e 8 kGy) nos grãos de soja crus e cozidos. As análises físicas realizadas foram o tempo de cocção e o tempo de hidratação dos grãos. As análises químicas realizadas foram a composição centesimal, digestibilidade da proteína, fatores antinutricionais, teor de isoflavonas e capacidade antioxidante (DPPH e ABTS). Os aspectos sensoriais foram determinados por análise sensorial realizada aplicando-se métodos analíticos de diferenciação para seleção de provadores, e método descritivo para determinar a qualidade da soja. Ao final, foi realizada análise estatística fatorial 3x2x2 (doses de irradiação x cultivares x tratamentos) para análise, comparação e discussão dos resultados obtidos. Os resultados mostraram diferenças nas medidas das análises físicas com a irradiação e com as diferentes cultivares. Além disso, as diferentes cultivares apresentaram diferenças na composição centesimal, digestibilidade, teor de fenólicos, isoflavonas e inibidor de tripsina. A cocção promoveu diferença em todos os componentes estudados, com exceção da digestibilidade protéica dos grãos. Por outro lado, a irradiação afetou os compostos antinutricionais, a digestibilidade protéica e o teor de isoflavonas agliconas. Os dados da análise sensorial mostraram que o sabor e a textura das amostras não diferiram entre os cultivares e não foram afetadas pela irradiação. / The soybean is a vegetable with high nutricional value, mainly due to its high protein content. Among the culture of grains, the soybeam is the most important in Brazil, what represents a greater incentive for the consumption of this food. However, a great claim of occidental consumer is its characteristic odor and flavor, known as beany flavor, which is provided by the action of lipoxigenase enzyme. The catalytic action exerted by this type of isoenzime on pollyunsaturated fatty acids, linolenic and linoleic acid of the soy grains, is one of the main factors responsible for the appearance of the carbonyl compounds, which cause the unpleasant flavor in grains. To enhance the organoleptic characteristics of soybeans, researchers have developed new cultivars, without the presence of lipoxigenase. The objective of this study was tof evaluate physical, chemical and sensorial differences between the two soy cultivar, with and without lipoxygenases (cultivars BRS 232 and BRS 257, of Embrapa, respectively) and to analyze the possible changes promoted by different radiation doses (0, 4 and 8 kGy) in raw and cooked soybean grains. The physical analyses were: time of cooking and hydration of the grains. The chemical analyses were: centesimal composition, protein digestibility, antinutritional factors, isoflavone content and antioxidant capacity (DPPH and ABTS). The sensory aspects were determined by sensorial analysis performed by appling analytical methods of differentiation for selection of panelists, and descriptive method to determine the quality of the soybean. At the end, factorial statistical analysis was performed 3x2x2 (irradiation doses X cultivars x treatment) for analysis, comparison and discussion of the obtained results. The results showed differences in physical analyses with the irradiation and between the two cultivars. Besides, the cultivars presented differences in the centesimal composition, digestibility fenolic content, isoflavone content and tripsin inhibitor. Cooking promoted difference in all the studied components, except for the proteic digestibility of the grains. On the other hand, the irradiation affected the antinutritional contents, the proteic digestibility and the content of aglicone isoflavones. Data from sensory analysis showed that the taste and the texture of the samples didn\'t differ between the cultivars and were not affected by the irradiation.

A soja é uma leguminosa com alto valor nutricional, devido principalmente a seu alto conteúdo protéico. Dentre a cultura de grãos, a soja caracteriza-se como a mais importante do país, o que representa um incentivo ainda maior para o consumo desse alimento. Porém, este alimento ainda sofre restrições por parte dos consumidores ocidentais, devido, principalmente a seu odor e sabor característicos, conhecidos como beany flavor, que é proporcionado pela ação da enzima lipoxigenase. A ação catalítica exercida por esse tipo de isoenzima sobre ácidos graxos poliinsaturados, ácido linolênico e linoléico, dos grãos de soja é um dos principais fatores responsáveis pelo aparecimento dos compostos carbonílicos, os quais causam o sabor desagradável em grãos. Para melhorar as características organolépticas da soja, pesquisadores desenvolveram novas cultivares, sem a presença da lipoxigenase. O objetivo deste trabalho foi avaliar diferenças físicas, químicas e sensoriais entre as cultivares de soja com lipoxigenase e sem lipoxigenase (cultivar BRS 232 e BRS 257, da Embrapa, respectivamente) e analisar as possíveis alterações promovidas por diferentes doses de radiação (0, 4 e 8 kGy) nos grãos de soja crus e cozidos. As análises físicas realizadas foram o tempo de cocção e o tempo de hidratação dos grãos. As análises químicas realizadas foram a composição centesimal, digestibilidade da proteína, fatores antinutricionais, teor de isoflavonas e capacidade antioxidante (DPPH e ABTS). Os aspectos sensoriais foram determinados por análise sensorial realizada aplicando-se métodos analíticos de diferenciação para seleção de provadores, e método descritivo para determinar a qualidade da soja. Ao final, foi realizada análise estatística fatorial 3x2x2 (doses de irradiação x cultivares x tratamentos) para análise, comparação e discussão dos resultados obtidos. Os resultados mostraram diferenças nas medidas das análises físicas com a irradiação e com as diferentes cultivares. Além disso, as diferentes cultivares apresentaram diferenças na composição centesimal, digestibilidade, teor de fenólicos, isoflavonas e inibidor de tripsina. A cocção promoveu diferença em todos os componentes estudados, com exceção da digestibilidade protéica dos grãos. Por outro lado, a irradiação afetou os compostos antinutricionais, a digestibilidade protéica e o teor de isoflavonas agliconas. Os dados da análise sensorial mostraram que o sabor e a textura das amostras não diferiram entre os cultivares e não foram afetadas pela irradiação. / The soybean is a vegetable with high nutricional value, mainly due to its high protein content. Among the culture of grains, the soybeam is the most important in Brazil, what represents a greater incentive for the consumption of this food. However, a great claim of occidental consumer is its characteristic odor and flavor, known as beany flavor, which is provided by the action of lipoxigenase enzyme. The catalytic action exerted by this type of isoenzime on pollyunsaturated fatty acids, linolenic and linoleic acid of the soy grains, is one of the main factors responsible for the appearance of the carbonyl compounds, which cause the unpleasant flavor in grains. To enhance the organoleptic characteristics of soybeans, researchers have developed new cultivars, without the presence of lipoxigenase. The objective of this study was tof evaluate physical, chemical and sensorial differences between the two soy cultivar, with and without lipoxygenases (cultivars BRS 232 and BRS 257, of Embrapa, respectively) and to analyze the possible changes promoted by different radiation doses (0, 4 and 8 kGy) in raw and cooked soybean grains. The physical analyses were: time of cooking and hydration of the grains. The chemical analyses were: centesimal composition, protein digestibility, antinutritional factors, isoflavone content and antioxidant capacity (DPPH and ABTS). The sensory aspects were determined by sensorial analysis performed by appling analytical methods of differentiation for selection of panelists, and descriptive method to determine the quality of the soybean. At the end, factorial statistical analysis was performed 3x2x2 (irradiation doses X cultivars x treatment) for analysis, comparison and discussion of the obtained results. The results showed differences in physical analyses with the irradiation and between the two cultivars. Besides, the cultivars presented differences in the centesimal composition, digestibility fenolic content, isoflavone content and tripsin inhibitor. Cooking promoted difference in all the studied components, except for the proteic digestibility of the grains. On the other hand, the irradiation affected the antinutritional contents, the proteic digestibility and the content of aglicone isoflavones. Data from sensory analysis showed that the taste and the texture of the samples didn\'t differ between the cultivars and were not affected by the irradiation.