Fragmentation of suberin and composition of aliphatic monomers released by methanolysis of cork from Quercus suber L., analysed by GC-MS, SEC and MALDI-MS

Suberin from extractive-free cork from Quercus suber L. was depolymerised by methanolysis using different sodium methanolate (NaOMe) concentrations. 1 % and 3 % NaOMe completely removed suberin from cork (54 %-56 % of extractive-free cork), but for lower concentrations there was incomplete solubilisation; with 0.05 % NaOMe, only approximately 80 % of total suberin was removed. The monomeric composition of the extracts differed significantly: for the 0.05 % NaOMe, only alkanoic acids and diacids were found; the yield of co-hydroxy acids increased with reactant concentration, as well as alkanols and ferulic acid. Results from light scattering, SEC and MALDI-MS showed that soluble oligomeric fragments containing suberinic acids were present in the methanolysis mixture. The molecular weight of these oligomeric fragments decreased with higher sodium methanolate concentrations.