NASCIMENTO, A. K. A.; NASCIMENTO, Adna Keren de Almeida.
Résumé:
Acacia mearnsii, commonly known as black acacia, is a native species from Australia
that belongs to the family Leguminosae and Mimosoideae. The use of its wood has
been destined to several purposes, such as in the cellulose industry, agglomerated
wood, pottery industry, tanning, among others. Its bark has excellent properties of
vegetal extractives, being rich in tannin and phenols. There are different methodologies
for the quantification of these extractives, among them the method of skin powder and
Stiasny. The objective of this study was to determine the parameters for the
quantification of tannic extract from the bark of Acacia mearnsii De Wild. by means of
gravimetric methods, in order to enable analysis reliable and low cost for other forest
species. The research was carried out in the Laboratory of Technology of Forest
Products of the Academic Unit of Forest Engineering, UFCG campus of Patos. The
black acacia bark from Rio Grande do Sul was used to produce the tannic extract in
powder form. The analysis of the quality of the extract was performed by the method
of the skin powder and Stiasny, being evaluated the total solids, moisture, soluble
solids, insoluble solids, soluble solids tannic and non-tannic. For statistical analysis, it
was divided into two stages, each with three replicates. In the first stage, the means of
the treatments were compared through the F test. In the second stage the results were
presented in a descriptive way, based on position and dispersion measurements. The
use of the powdered extract and the porous crucible for the analysis of parameters
(such as soluble solids and total solids) are recommended. Higher levels of tannins
were observed when skin powder was used (greater than 75%) when compared to
formaldehyde (less than 70%). The methodology applied in this study has presented
good reliability and low costs for the determination of tannins in tannic extract powder,
which will be useful for future research involving other forest species.
