Antioxidant activity and possible bioactive components in hydrophilic and lipophilic fractions from the seaweed Halimeda incrassata

Hydrophilic and lipophilic fractions, obtained from the marine algae Halimeda incrassata (J.Ellis) J.V.Lamouroux, Halimedaceae, were studied by using the ²-carotene-linoleate assay system. In case of hydrophilic fractions, the total phenolic compounds were quantified and two of their components were identified as salicylic and ferulic acids. From the lipophilic fraction, fatty acid composition was studied. The highest antioxidant activities values were found on the polar fractions containing phenolic acids. The total phenolics content on the hydrophilic fractions was 255 μg of gallic acid equivalents/g of fresh seaweed. To further characterize H. incrassata chemical composition, the total lipid content was quantified (7.4 mg per gram of dried algae) as well as the saturated and unsaturated fatty acids ratio (1:1.46). In summary, this paper adds more convincing evidences in support of the antioxidant abilities of the lyophilized aqueous extract of Halimeda incrassata and it also relates this bioactivity, for the first time, with particular phenolic components of the extract. Altogether, these results represent another step towards the use of this natural product as drug candidates.

Isoflavones in processed soybean products from Ecuador

Soy products produced in Ecuador, with a local developed and cultivated soybean variety (INIAP 306), were analysed for isoflavone content and profile. The products presented high total isoflavone contents, varying from 53 to 106 mg/100 g (wet basis, expressed as aglycones), the lowest content being for okara and the highest for the low fat soybean flour obtained by extrusion cooking of the seeds at the field moisture. Soy nuts showed the same content of isoflavones than the seeds, but with lower amounts of malonylglycosides and higher of the deesterified beta-glycosides. The malonylglycosides were the predominant form of the isoflavones in the flours, and the beta-glycosides in soymilk and textured soy protein. Genistein derivatives were the compounds present in the highest proportions in all the products analysed.

Produtos derivados de soja produzidos no Equador, com uma variedade de soja (INIAP 306) desenvolvida e cultivada localmente, tiveram o teor e perfil de isoflavonas determinados através de cromatografia líquida de alta eficiência. Os produtos apresentaram altos conteúdos de isoflavonas, variando de 53 a 106 mg/100 g (base úmida, expresso como agliconas), sendo o menor conteúdo encontrado em okara e o maior na farinha parcialmente desengordurada obtida através de extrusão das sementes. Os snacks de soja apresentaram o mesmo conteúdo de isoflavonas que as sementes, mas com quantidades menores de malonilglicosídeos e maiores de beta-glicosídeos desesterificados. Os malonilglicosídeos foram as formas predominantes encontradas nas farinhas e os beta-glicosídeos no leite e na proteína texturizada de soja. Os derivados de genisteína foram os compostos presentes nas maiores proporções em todos os produtos analisados.

Avaliação do teor de isoflavonas de "suplementos nutricionais à base de soja" / Isoflavone content of soy dietary supplements

Devido aos possíveis efeitos benéficos, diversos produtos à base de soja (gérmen, extrato), na forma de cápsulas ou comprimidos, surgiram recentemente no mercado como fontes de isoflavonas. Neste trabalho avaliaram-se o teor e o perfil de isoflavonas dos produtos comercializados em drogarias e farmácias locais (São Paulo), para verificar se estavam de acordo com o especificado pelos fabricantes. A determinação foi realizada através de cromatografia líquida de alta eficiência com detetor com arranjo de diodos, de acordo com Genovese & lajolo (2001b). Os resultados mostraram que os produtos à base de soja apresentam teor de isoflavonas muito abaixo do valor indicado nos rótulos, entre 27 por cento e 86 por cento a menos...

Atividade inibitória de tripsina do feijão (Phaseolus vulgaris L. ): avaliação crítica dos métodos de determinação / Trypsin inhibitory activity of beans (Phaseolus vulgaris L. ): critical evaluation of methods for determination

High values of residual trypsin inhibitory activity found for heat-treated beans indicated the occurrence of artifices due to the methodology. A critical evaluation of the methods in use and of possible interferents was performed trying to determine the most adequate way of measuring residual trypsin inhibitory activity. Results showed that extraction conditions, pH of reaction and sample preparation are responsible for significant alterations of the values found, requiring careful standardization. This is the first report about the influence of lyophilization upon residual trypsin inhibitory activity of cooked beans.