Biblioteca do Café

URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/1

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2019 - 20202

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Tem arquivos: SimAssunto: search.filters.subject.Capillary electrophoresis

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    Development of a method for simultaneous analysis of caffeine and taurine in energy drinks by micellar electrokinetic chromatography with diode-array detector
    (Sociedade Brasileira de Ciência e Tecnologia de Alimentos, 2019-09-19) Alves, Alane Cangani; Meinhart, Adriana Dillenburg; Teixeira Filho, José; Godoy, Helena Teixeira
    The objective of this study was to develop, optimize and validate a fast and reliable method for the simultaneous determination of caffeine and taurine contents by micellar electrokinetic chromatography with diode array detector, using direct and indirect detection concomitantly. Multivariate statistical techniques were used as a central composite design and the simultaneous optimization method of responses of Derringer and Suich were used for optimization. The method was applied in the analysis of 73 samples of energy drinks commercialized in Brazil. The optimized method employed a capillary tube with an extended bulb of 50 µm i.d. x 72 cm total length, an electrolyte containing 16.20 mmol.L-1 of benzoic acid and 39.90 mmol.L-1 of SDS, a pH value of 7.26, + 30 kV voltage, direct detection of caffeine at 274 nm and indirect detection of taurine at 230 nm. Validation parameters have demonstrated the reliability and applicability of this method. It was found that more than 50% of the samples were out of the legal limits determined by the Brazilian government regarding the taurine content and 68 % contained caffeine below the value declared on the label. Therefore, the need for greater control concerning the composition of these drinks exists.
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    Microsatellite DNA fingerprinting of Coffea sp. germplasm conserved in Costa Rica through singleplex and multiplex PCR
    (Crop Breeding and Applied Biotechnology, 2020) Sánchez, Elodia; Solano, William; Gatica-Arias, Andrés; Chavarría, Max; Araya-Valverde, Emanuel
    A large collection of coffee genetic resources is conserved in Costa Rica. In this study, microsatellite DNA fingerprinting of coffee through singleplex and multiplex PCR approaches coupled with capillary electrophoresis are described. To validate both methods, germplasm of Coffea spp. (Arabica and non-Arabica) and intraspecific F1 hybrids were analyzed using fourteen microsatellite markers. It was observed that through both PCR methods the fingerprinting profile of a subset of samples was identical. The genetic analyses revealed that non-Arabica coffee displayed greater genetic variation than Arabica coffee did. In addition, microsatellite analyses allowed the separation of C. arabica from other species using the principal coordinate analysis (PCoA) approach. The neighbor-joining tree clustering analysis revealed either a grouping of wild genotypes separated from cultivars of C. arabica, or a relation of intraspecific F1 hybrids with parental lines. The utility of our methodology for the characterization of F1 hybrids not previously analyzed through SSR (Simple Sequence Repeats) fingerprinting is demonstrated.