Bark Characterisation of the Brazilian Hardwood Goupia glabra in Terms of Its Valorisation

The bark of Goupia glabra trees grown in a native forest area in the Amazon region of Brazil was anatomically and chemically characterised for potential use as a chemical source for bio-refineries. The bark is silvery-grey to reddish-grey, with a scaly rhytidome composed of 2 to 3 periderms with a small phellem content. The phloem has abundant sieve tube members and a conspicuous presence of sclerified nodules of fibersclereids or sclereids; no fibers were observed. The bark had the following average composition (dry mass): 5.2% ash, 24.6% total extractives, 1.1% suberin, and 43.8% total lignin. The polysaccharide composition showed a high ratio of xylan hemicelluloses to cellulose. The ethanol-water bark extract showed high antioxidant capacity. The chemical characterisation of different granulometric fractions showed that extractives were present preferentially in the finest fractions, particularly with enrichment in ethanol solution.