resumo
The structural features of macromolecular components of cork (suberin, lignin, cellulose and hemicelluloses) from Quercus suber L. used for the production of stoppers were assessed after their isolation and purification. Suberin is the major component of cork (ca. 44%) and is constituted mainly by hydroxy fatty acids (C-14-C-26). Cork lignin was found to be highly condensed (16.2%) and revealed a syringyl:guaiacyl:p-hydroxyphenyl (S:G:H) ratio of 26:71:3 with predominant beta-O-4' (0.38%), beta-5', beta-beta and tetrahydrofuran (THF) type (totally ca. 27%) structures. Cork lignin also has a remarkable amount of ferulic acid structures, which are considered the binding point between lignin and suberin. The cellulose of cork cells (17.2%) is a typical cellulose I polymorph with a degree of crystallinity (DC) of 70.3% and an average crystallite width of 3.5 nm. The major hemicellulose of cork is glucuronoxylan (near 6.0%) possessing a molar Xylp:MeGlcpA ratio of 14:1.
palavras-chave
CHEMICAL-COMPOSITION; REPRODUCTION CORK; LIGNIN; VARIABILITY
categoria
Forestry; Materials Science
autores
Branco, DG; Campos, JR; Cabrita, L; Evtuguin, DV
nossos autores
Dmitry Evtyugin
Professor Associado com Agregaçãoagradecimentos
This work was developed within the scope of the project NEWASHCORK (POCI-01-0247-FEDER-034048) financed by ANI and co-financed by FEDER and supported by CICECO-Aveiro Institute of -Materials, FCT Ref. UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MCTES.