Comparative Chemical and Spectroscopic Characterization of Cork from Quercus variabilis and Quercus suber of Different Geographic Origins

Cork is receiving increasing attention as a renewable and biodegradable biomaterial for sustainable industries. This study compares the chemical composition and molecular fingerprints of cork from Quercus variabilis (Republic of Korea and China) and Quercus suber (Portugal and Italy), focusing on species- and provenance-dependent differences. Major structural components (suberin and lignin) were quantified, and compositional features were characterized using Fourier-transform infrared (FT-IR) spectroscopy and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). Distinct differences were observed across both species and geographic origins. The Q. variabilis sample from the Republic of Korea showed the highest suberin content (50.19%), whereas Portuguese Q. suber exhibited the highest lignin content (24.90%). Py-GC/MS profiles further differentiated the provenances: Italian cork showed the highest yield of aliphatic products (161.1 mg g–1), while the Chinese sample contained elevated levels of aromatic products (63.34 mg g–1), including phenolic compounds that may be associated with antioxidant activity. Overall, the combined FT-IR and Py-GC/MS results indicate that cork chemistry is shaped jointly by species and provenance. These findings provide an origin-aware chemical basis for material selection for example, suberin-rich corks may be advantageous for barrier- and flexibility-related uses, whereas lignin-rich corks may better support applications requiring higher rigidity and durability and support the potential of Q. variabilis as a sustainable cork resource in East Asia.