resumo
A comparative study on the chemical composition of oak cork (Quercus suber L.) and corresponding industrial residues and birch (Betula pendula L.) outer bark is reported. Cork oak samples have lower extractives contents (6-9%) and higher contents of carbohydrates and lignin (23-27 and 33-38%, respectively) than those found for birch outer bark (40, 6 and 9%, respectively); suberin contents accounted for around 30% of cork, 11% of industrial cork powder and 45% of birch outer bark. Analysis of the suberin monomeric composition revealed that C18 and C22 omega-hydroxyfatty acids (including mid-chain epoxy- and dihydroxy-derivatives), followed by alpha,omega-dicarboxylic acids, are the main components in both suberins, with 9,10-epoxy-18-hydroxyoctadecanoic, 18-hydroxyoctadec-9-enoic, 9,10,18-trihydroxyoctadecanoic and octadec-9-enoic acids as the major components. The differences in the relative amounts of these acids in the suberin samples and the impact on the potential exploitation of the different industrial by-products are discussed. (C) 2008 Elsevier B.V All rights reserved.
palavras-chave
CHEMICAL-CHARACTERIZATION; REPRODUCTION CORK; POLYURETHANES; URETHANES; POLYSACCHARIDES; OXYPROPYLATION; BIOREFINERIES; METHANOLYSIS; VARIABILITY; HYDROLYSIS
categoria
Agriculture
autores
Pinto, PCRO; Sousa, AR; Silvestre, AJD; Neto, CP; Gandini, A; Eckerman, C; Holmbom, B
nossos autores
Alessandro Gandini
Investigador
Andreia Fernandes de Sousa
Investigador Principal
Armando Jorge Domingues Silvestre
Professor Catedrático
Carlos Pascoal Neto
Diretor do Raizagradecimentos
Amorim group is gratefully acknowledged for supplying cork and cork by-products samples; Metsa-Botnia, Kaskinen is gratefully acknowledged for supplying birch bark samples.