Avaliação das variáveis analíticas do método de Folin-Ciocalteu para determinação do teor de taninos totais utilizando como modelo o extrato aquoso de folhas de psidium guajava L. Evaluation of analytical variables of the Folin-Ciocalteu method for the quantitation of the total tannins content using a Psidium guajava L. leaves aqueous extract as a model
| Autor: | Simone Gasparin Verza, Maria T. Kreinecker, Valquíria Reis, Amélia T. Henriques, George González Ortega |
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| Jazyk: | English<br />Spanish; Castilian<br />Portuguese |
| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Química Nova, Vol 30, Iss 4, Pp 815-820 (2007) |
| Druh dokumentu: | article |
| ISSN: | 0100-4042 1678-7064 |
| DOI: | 10.1590/S0100-40422007000400011 |
| Popis: | The main analytical variables of a modified Folin-Ciocalteu method were studied by UV-Vis and gradient HPLC-PDA methods, using purified (PC) and technical grade (TGC) casein. Rutin and an aqueous extract of Psidium guajava L. leaves were used as models. The best results were ascribed to TGC. Certainly PC bonds the polyphenols of the P. guajava extract better than TGC, but TGC afforded better precision. A lack of specificity occurred when rutin was analyzed together with the P guajava extract. Additional analyses performed with the flavonoid fraction of P. guajava extract by HPLC-PDA had confirmed that casein was able to bind catechin, gallic acid and P. guajava flavonoids in a non-specific way. |
| Databáze: | Directory of Open Access Journals |
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