TY - JOUR T1 - Characterization of Heartwood Lignin Fractions from <em>Quercus robur</em> L. and <em>Quercus petraea</em> (Matt) Liebl., the Main Oak Species Used for Barrel Making JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 49 LP - 55 DO - 10.5344/ajev.1998.49.1.49 VL - 49 IS - 1 AU - Nicolas Vivas AU - Isabelle Pianet AU - Guy Bourgeois AU - Christiane Vitry AU - Christian Servens AU - Yves Glories Y1 - 1998/01/01 UR - http://www.ajevonline.org/content/49/1/49.abstract N2 - Various methods were used to characterize three kinds of lignin fractions from the heartwood of Quercus robur and Q. petraea. UV analysis and determination of the mean molecular mass showed that the first fraction, soluble in a hydroalcoholic medium and extractable with dichloromethane, is a mixture of oligomer lignins with a mass below 800 Da, highly enriched with free phenol aldehyde and lyoniresinol. The LE and LD fractions, extractable with ethanol and dioxane, respectively, are relatively pure lignins. LE and LD thioacidolysis products, and LE sine contains ellagic acid. IR and GC-MS analysis of their thioacidolysis products enabled us to demonstrate the heterogeneity of these two lignins. LE is characterized by an S/G close to 1, while LD has an S/G ratio between 1.41 and 1.67, characteristic of lignins rich in syringyl units. ER -