Fragmentation of suberin and composition of aliphatic monomers released bymethanolysis 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 b y methanolysis using different sodium methanolate (NaOMe) concentrations. 1 % and 3 % NaOMe completely removed suberin from cork (54 %-56 % of extract ive-free cork), but for lower concentrations there was incomplete solubilis ation; with 0.05 % NaOMe, only approximately 80 % of total suberin was remo ved. 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 oligome ric fragments containing suberinic acids were present in the methanolysis m ixture. The molecular weight of these oligomeric fragments decreased with h igher sodium methanolate concentrations.