Tannin quantification and chemical-energetic characterization of biomass residues of Bertholletia spp. and Lecythis’ spp. fruits

Abstract

Biomass residues originated from agroforestry systems has been demonstrating great usage potential for the pharmaceutical, textile and energy industries. In the Amazon region, the use of these materials can stimulate the sustainable economic development of extractive communities and agroforestry systems. However, for a better use of this material, it is necessary to quantify and qualify the chemical components present in these residues. Keeping that in mind, our research aimed to quantify the presence of condensed and hydrolysable tannins, and to chemically and energetically characterize the Bertholletia excelsa and Lecythis pisonis’ fruit residues, with the intent to assess the usage potential for this biomass resource in different industries. The studied material was collected from local extractives and merchants. Tannin quantification was performed through thin layer chromatography (TLC) method and the total values of extractives, lignin and holocellulose were also quantified. The energy potential was determined by the variables of apparent density, gravimetric yield, superior calorific power and charcoal’s immediate chemistry (the charcoal was produced at 450 ºC). The associations between variables were determined by a linear correlation. The TLC for condensed tannin was positive for B. excelsa. As for the TLC of hydrolysable tannins, the results were negative for both materials. The high levels of lignin and extractives in fruit’s residues of both species demonstrate the energy potential of this material. Our results may favor the use of B. excelsa’s residues for the production of polymers and adhesives, as well as other non-wood residues with high content of lignin, fixed carbon and calorific power in energetic products.

Keywords: Bertholletia excelsa; Lecythis pisonis; Brazillian chestnut; tannins; biomass residues from agroforestry systems.