Determinação do teor de taninos na casca de Eucalyptus spp

Abstract

The objective of this study was to determine the tannin contents in the bark of twenty-five species of Eucalyptus through two extraction methods, one using hot water and the other a sequence of toluene and ethanol. The results showed that the extraction methods presented significant differences in the tannin contents. The method using the sequence toluene and ethanol, for most of the species, promoted a larger extraction of tannin. The hot water method presented higher contents of tannin for Eucalyptus cloeziana (40,31%), Eucalyptus melanophoia (20,49%) and Eucalyptus paniculata (16,03%). In the toluene and ethanol method the species with higher tannin content was Eucalyptus cloeziana (31,00%), Eucalyptus tereticornis (22,83%) and Eucalyptus paniculata (17,64%). The Eucalyptus cloeziana presented great potential as commercial source of tannin, independent of the extraction method considered.