Navegando por Autor "Teixeira, João Paulo F."

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    Método de separação e determinação das bases purinas cafeína e teobromina
    (Instituto Agronômico (IAC), 1980) Spoladore, Dayse Soave; Teixeira, João Paulo F.
    A method for separation and determination of caffeine and theobromine in plant material by chromatographic column is presented. The alkaloids were extracted from the plant material (cocoa bean) by MgO powder, and separated in chromatographic column -using alumina (A1»0 :! ) as support and the solvent was 5% butanol in water washed chloroform. The compound present in the effluent was determinated by spectrofotometry at 276.5nm. The results obtained were considered satisfactory for both, standard and plant material alkaloids solutions.
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    Novo procedimento para avaliação do teor de cafeína em grãos de café
    (Instituto Agronômico (IAC), 1980) Spoladore, Dayse Soave; Teixeira, João Paulo F.
    The objective of this study was to establish a rapid method for analysis of caffeine content in green coffee beans. Modifications were made in the usual method (AOAC) by the elimination of KOH 1% washing step and reduction of digestion time using hydrogen peroxide. Both methods were applied to green coffee beans with different caffeine content. The modified method was more rapid and showed similar results to the AOAC method. It can be applied to determine caffeine content in green coffee beans.