Characterization of the bark from residues from mate tree harvesting (Ilex paraguariensis St. Hil.)

The goal of this study was to evaluate the microstructure and the chemical composition of mate (Ilex paraguariensis) bark. The results of this study showed existence of periderm and suggest the presence of phenolic compounds linked to sources of dietary fibre in the sclerenchyma and in the suber. Mate bark showed significantly higher concentrations of dietary fibres, minerals and total polyphenols when compared to those detected in mate leaves. Only protein, lipid, and condensed tannins were detected in larger amounts in the leaves. The presence of uronic acid in the samples reveals the presence of pectin and confirms its identification through fluorescence micrography of mate bark. The monosaccharide composition of the I. paraguariensis not only helps to confirm its authenticity but also suggests the presence of less branched and more insoluble polymers in mate bark, which is consistent with the detection of a higher content of insoluble fibres in this tissue.