Characterization of the major components in bark from five Japanese tree species for chemical utilization

Summary

Characterization of the major components in bark from five Japanese tree species, Pinus densiflora, Larix leptolepis, Cryptomeria japonica, Fagus crenata, Quercus mongolica, was performed from a viewpoint of chemical utilization. Relatively high yields of formaldehyde-condensable polyphenols were obtained from the bark of P. densiflora (22.5%) and L. leptolepis (20.8%) by 1% NaOH extraction. The alkali insoluble residue contained large amounts of neutral sugars (26.1%–40.7%) in comparison with untreated bark. Glucose was generally the dominant sugar in the residue, although the major neutral sugar content in F. crenata was xylose. By successive treatment with 1% NaOH and acid chlorite, a marked decrease in lignin content was observed in P. densiflora. In the other tree species, bark lignin was resistant to acid chlorite treatment to a certain extent.