Study of cork from Quercus suber L. with and without yellow spot: aromatic fraction and cellular structure

Abstract

The effect of the presence of yellow spot in cork from Quercus suber was studied in relation to volatile compounds and the influence on the cellular structure to better understand cork as a material. The volatile compounds from cork were analyzed using thermal desorption combined with gas chromatography (TD-GCMS). This methodology had identified 103 compounds in cork samples with and without yellow spot. All the samples showed compounds from different families according to its chemical structure such as aromatic compounds (36), carboxylic acids (11), aliphatic alcohols (9), alkanes (9), aliphatic aldehyde (8), chlorate compounds (5), ester (5), terpene (5), alkene (4), furane (4) and aliphatic ketone (1). Vanillin was the most abundant compound followed by isoeugenol. Chlorinated compounds such as 2,4,6-Trichlorophenol, 2, 4-Dichlorophenol and 2,4,6-Trichloroanisole have only been identified in cork with yellow spot. This study showed differences in aromatic cork profile according to the presence or absence of yellow spot. Cellular structure of cork seems to be influenced by the presence of yellow spot due to the appearance of changes in the level of cell corrugation and the degree of separation of the layers of cell wall. These results allow to expand the knowledge about changes produced in cork by the presence of yellow spot