Preconcentration of polar phenolic compounds from water samples and soil extract by liquid-phase microextraction and determination via liquid chromatography with ultraviolet detection.

2016

Development of methodology for the determination of organic acids in must, grape juice and wine by high performance liquid chromatography (HPLC).

2012

Contents and bioconversion of B-glycoside isoflavones to aglycones in the processing conditions of soybean tempeh.

The objective of this work was to evaluate the effect of the processing conditions of soybean tempeh on the contents of ??glycoside isoflavones and on their bioconversion into aglycones. Different times of soaking (6, 12, and 18 hours), cooking (15, 30, and 45 minutes), and fermentation (18, 24, and 30 hours) with Rhizopus oligosporus at 37°C were evaluated for tempeh preparation. Grains from the cultivar 'BRS 267' were used, and the experiment was carried out according to a central composite design (23). The response functions comprised the contents of genistin, malonyldaidzin, malonylgenistin, daidzein, and genistein, quantified by ultraperformance liquid chromatography (UPLC). Soaking, cooking, and fermentation times change the content, profile, and distribution of the different forms of isoflavones in tempeh. The highest bioconversion of glycoside isoflavones into aglycones occurred in 6?hour soaked soybean grains, whose cotyledons were cooked for 15 minutes and subjected to 18?hour fermentation. RESUMO:O objetivo deste trabalho foi avaliar o efeito das condições de processamento do tempeh de soja sobre o conteúdo de isoflavonas ??glicosídeos e sobre sua bioconversão em agliconas. Diferentes tempos de maceração (6, 12 e 18 horas), cozimento (15, 30 e 45 minutos) e fermentação (18, 24 e 30 horas) com Rhizopus oligosporus a 37°C foram avaliados na preparação do tempeh. Foram utilizados grãos da cultivar 'BRS 267', e o experimento foi realizado de acordo com um delineamento composto central (23). As funções?respostas compreenderam o teor de genistina, malonildaidzina, malonilgenistina, daidzeína e genisteína, quantificadas por cromatografia líquida de ultraeficiência (CLUE). Os tempos de maceração, cozimento e fermentação alteraram o conteúdo, o perfil e a distribuição das diferentes formas de isoflavonas no tempeh. A maior bioconversão de ??glicosídeos em agliconas ocorreu em grãos de soja macerados por 6 horas, cujos cotilédones foram cozidos por 15 minutos e submetidos à fermentação por 18 horas.

Influence of the vintage, clone and rootstock on the chemical characteristics of Syrah tropical wines from Brazil.

In the Northeast of Brazil, vines can produce twice a year, because annual average temperature is 26ºC, with high solar radiation and water availability for irrigation. Many cultivars have been tested according to their adaptation to the climate and soil, and the main variety used for red wines is Syrah. This work aimed to evaluate five clones of Syrah, grafted on two rootstocks, in two harvests of the second semester of 2009 and 2010, according to the chemical analyses of the wines.The clones evaluated were 100, 174, 300, 470 and 525, the rootstocks were Paulsen 1103 and IAC 313 (Golia x Vitis caribeae). Grapes were harvested in November 2009 and 2010 and the yield was evaluated. Climate characteristics of each harvest was determined and correlated to the results. Wines were elaborated in glass tanks of 20 L, with alcoholic fermentation at 25ºC for seven days, then wines were pressed and malolactic fermentation was carried out at 18ºC for 20 days. The following parameters were analyzed: alcohol content, dry extract, total anthocyanins, total phenolic index. High performance liquid chromatography was used to determine tartaric, malic, lactic and citric organic acids. Results showed that wines presented different concentrations of classical analyses, phenolics and organic acids according to the harvest date, rootstocks and clones. Principal component analysis was applied on data and clusters with wine samples were formed, explaining the variability, and results are discussed.