Análise química da cortiça das árvores de Kielmeyera coriacea Mart.

Abstract

This study aimed to analyze the chemical composition of the cork from Kielmeyera coriacea Mart. (pau-santo) trees in different diameter classes, as well as to analyze qualitatively the suberin. Corks from 20 Kielmeyera coriacea trees were randomly collected in the diameter at breast height (DBH). The Kielmeyera coriacea forest plantation is located in Luminárias, Minas Gerais. The trees were grouped into the following diameter classes: Class 1 (7.6 to 10.38 cm), 2 (10.38 to 13.17 cm), 3 (13.17 to 15.95 cm), 4 (15, 95 to 18.73 cm) and 5 (18.73 to 21.51 cm). The determination of the cork chemical composition was carried out by the general method for chemical analysis of wood, and by the removal of suberin by hydrolysis. The qualitative characterization of suberin was performed by Fourier transform infrared spectroscopy (FTIR). The chemical composition of cork from Kielmeyera coriacea trees was 19.87% extractives, 27.84% suberin, 57.67% lignin and 1.14% ash. These results were similar to those found in the literature, except for the lignin content. The diameter of the trees was not a factor of influence in the cork chemical composition. The FTIR analysis showed the presence of aliphatic groups, OH groups and C=O groups, all of them characteristics of the suberin.