Quantificação de extrato tânico proveniente da casca de Acacia mearnsii De Wild. por métodos gravimétricos.

Abstract

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.