Determination of folate in beans

Orientador: Helena Teixeira GodoyDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: No Brasil, o feijão obteve ampla difusão cultural e atualmente o país é considerado o maior produtor e consumidor do grão. Essa leguminosa é citada internacionalmente como uma fonte de folatos, um grupo de vitaminas pertencentes ao complexo B. Entretanto, é quase inexistente o levantamento de dados sobre o teor de folatos em feijões brasileiros. Os folatos participam de dois processos biológicos importantes: o ciclo de metilação, que consiste na transferência de carbonos e a biossíntese do DNA, fundamental para a manutenção das células. Sua deficiência está relacionada a problemas na formação do tubo neural em fetos, doenças cardiovasculares e alguns tipos de câncer. Deste modo, torna-se necessário um método eficiente para detectar e quantificar os folatos presentes nas diferentes variedades de feijão consumidas no país. O objetivo do trabalho foi determinar o teor de folatos por cromatografia líquida de alta eficiência (CLAE), utilizando diferentes métodos de hidrólise enzimática, além de aplicar o método em quatro variedades de feijão comum (carioca, preto, vermelho e branco) e uma variedade de feijão de corda, avaliando o efeito do cozimento sobre os folatos presentes. Em comparação como os outros tratamentos, apenas o tratamento tri-enzimático foi mais eficiente na identificação e quantificação dos folatos. Nos feijões, foram detectatos somente o tetraidrofolato (THF) e o 5-metiltetraidrofolato (5-MTHF). Os folatos foram separados utilizando uma coluna C18 como fase estacionária, solução acidificada com ácido acético/acetonitrila como fase móvel, e detectados por fluorescência (?exc. 290 nm e ?emis 360 nm). Os limites de detecção e quantificação foram, respectivamente, 0,9 ng/mL e 5,4 ng/mL para o THF, e 0,7 ng/mL e 4,2 ng/mL para o 5-MTHF. O método apresentou linearidade na faixa de trabalho, além de repetitividade e reprodutibilidade. Nos feijões crus o teor de THF variou de 20,3 a 1484 µg/100g e o teor de 5-MTHF variou de não determinado a 60 µg/100g. Já nos feijões cozidos, que foram processados de acordo com a recomendação dos fabricantes, o teor de THF variou de 15,3 a 1207 µg/100g, e de 5-MTHF variou de não determinado a 31,3 µg/100g. Observou-se que as perdas por processamento foram significativas e diferentes entre as variedades de feijões, sendo o 5-MTHF o composto mais suceptível. Além disso, as perdas foram ainda maiores quando o feijão foi submetido ao remolho antes do cozimento, como no feijão branco. No feijão de corda foram encontrados os maiores teores de folatos, embora tenha sido encontrado apenas o THF. Houve diferenças significativas entre os três lotes de cada variedade, que pode ser devido à diversidade das condições de cultivo e variação de genótipos do feijão. Os dados mostram que o feijão brasileiro é uma boa fonte de folatos presentes na dietaAbstract: The beans have been widespread used as a traditional food in Brazil and nowadays the country is the largest producer and consumer of this grain. This legume is referred internationally as a source of folates, which belong to the group of vitamins B complex. However, the data about folates from Brazilian beans are almost nonexistent. Folates take part in two important biological processes: the methylation cycle, that is the transfer of carbon, and the biosynthesis of the DNA, essential for cell maintenance. The folates deficiency is related to problems in neural tube formation in fetuses, cardiovascular disease and some cancers. Thus, it becomes necessary to develop an efficient method for detecting and quantifying folate present in different varieties of beans consumed in Brazil. The aim of this study was to determine the content of folates by high performance liquid chromatography (HPLC), using different enzymatic hydrolysis methods, and apply the method on four common bean (carioca, black, white and red) and a cowpea, as well as evaluating the effect of cooking process on the content of folates. The tri-enzyme treatment compared to other treatments was the most efficient for identification and quantification of the folates. Only the tetrahydrofolate (THF) and 5-methyltetrahydrofolate (5-MTHF) were detected in the beans. Folates were separated using a C18 column as the stationary phase, acidified solution with acetic acid/acetonitrile as the mobile phase, and were detected by fluorescence (290 nm and ?exc. ?emis 360 nm). The limits of detection and quantification were, respectively, 0.9 ng/mL and 5.4 ng/mL for THF, and 0.7 ng/mL and 4.2 ng/mL for 5-MTHF. The method was linear in the working range including repeatability and reproducibility. In raw beans the THF content ranged from 20.3 to 1484 µg/100g and the amount of 5-MTHF ranged from 60 µg/100g to not determined. Whereas for the cooked beans, which were cooked according to the manufacturer's recommendations, the content of THF ranged from 15.3 to 1207 µg/100g and the amount of 5-MTHF ranged from 31.3 µg/100g to not determined. It was observed that the losses due the process were significant between the different varieties of beans, were the 5-MTHF compound was more susceptible to degradation. Furthermore, the losses were even greater when the beans were subjected to soaking before cooking, as in white beans. In cowpea were found the highest levels of folates, although it has been found only THF. There were significant differences among the three batches of each variety, which may be due to the different growing conditions and variation in the bean genotypes. The data show that the Brazilian beans are a good source of folate present in the dietMestradoCiência de AlimentosMestra em Ciência de Alimento

Chlorogenic acids and flavonoid extraction during the preparation of yerba mate based beverages

This study determined the content of chlorogenic acids (CA) and rutin during successive aqueous extraction of yerba mate for tererê and chimarrão from four yerba mate types (smooth, native, traditional and coarse ground). Aqueous extracts were prepared aiming to simulate homemade procedure by partially (chimarrão) or completely (tererê) immersing the herb into hot (chimarrão) or cold (tererê) water (30 times consecutively). The content of CA and rutin in the aqueous extracts was compared to those in methanolic extracts (exhaustive extraction). Tererê aqueous extracts gave higher amounts of all phenolic compounds (2.5 to 6 times higher than chimarrão). Among chimarrão, course-ground aqueous extracts had on average 15% more PC (phenolic compounds). By comparing the content in aqueous and methanolic extracts, after 30 successive extractions, on average 14% of the total amount of CA in yerba mate leaves and 9% of rutin were transferred to the chimarrão extracts, whereas tererê achieved between 40% and 100% of transference. Thus, this study shows that CA and rutin are continuously extracted during the preparation of aqueous extracts of chimarrão and tererê, favoring a high intake of these antioxidant species by consumers102348354COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informação2012/1256

Optimization of the preparation conditions of yerba mate tea beverage to maximize chlorogenic acids extraction

The beverage obtained from the yerba mate tea, besides being the most consumed in Brazil, has high concentrations of chlorogenic acids. In this study, a central composite design was employed to establish the best infusion time, temperature and water volume to maximize the extraction of chlorogenic acids 5-caffeoylquinic (5CQ), 3.4-dicaffeoylquinic (3.4 DQ), 3.5-dicaffeoylquinic (3.5 DQ) and 4.5-dicaffeoylquinic (4.5 DQ), from the leaves and stems of yerba mate tea (beverage ready for consumption). Analyses were performed by high-performance liquid chromatography and the optimum conditions were obtained through the use of the desirability function of Derringer and Suich. The maximum chlorogenic acids content in the beverage was obtained when the infusion was prepared with 2 g of mate tea, in 300 mL of water at 95 °C, under infusion for 16 min. The optimal conditions were applied for the preparation of beverages from 15 commercial samples of yerba mate tea, and it was observed that the sum of the concentration of the four compounds showed variation of up to 79 times between the average of the samples, which can be attributed to climatic conditions of cultivation of the plant and/or of processing.722219223FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2012/12565-

Content of lutein in aqueous extracts of yerba mate (ilex paraguariensis St. Hil)

Lutein is the main carotenoid in green leafy vegetables. It has been associated to reduction of risks of progression of macular degeneration, therefore, the consumption of lutein through diet is essential to help prevention of blindness and cataract. In this study, we investigated lutein in aqueous extracts of yerba mate by ultra high performance liquid chromatoraphy and mass spectrometry. Different commercial types of yerba mate for chimarrão (smooth, traditional and coarse-ground) and terere were analyzed. The effect of temperature on the amount of lutein extracted was also investigated. We observed that terere extracts presented lutein content higher (17 μg) than chimarrão extracts, and among chimarrão commercial types, coarse-ground presented the highest lutein content (in average 9.5 μg). We also verified that water temperature incremental favored the lutein migration to aqueous extract. The levels of lutein found in the yerba mate infusions investigated in this study were superior to others tea drinks, showing that aqueous extracts of yerba mate can contribute significantly to the ingestion of lutein82165171COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informação2012/12565; 2010/19863-