Influence of Hydrothermal Treatment on Hemicellulose Structure in Cryptomeria japonica

The influence of hydrothermal treatment (HTT) on the hemicellulose, i.e. glucomannan/galactoglucomannan (GM/GGM) and arabinoglucurono-xylan (AGX) in Japanese cedar was examined using mild temperatures (95 degrees C and 120 degrees C) for its kiln drying. Based on infrared spectra, only a slight change due to HTT was observed in the hemicellulose chemical structure. The quantitative changes of the major chemical components including lignin, cellulose, and hemicellulose also exhibited slight differences among samples. However, the molecular chain-length composition of GM/GGM and AGX in the cell walls decreased clearly with HTT, as well as with an increase in temperature. Also, it was found that the strength of the interaction between cellulose and hemicellulose molecules such as GM/GGM and AGX in cell walls decreased depending on the increase in HTT temperature. These results showed that the polymeric structure of GM/GGM and AGX was degraded by hydrolysis at 95 degrees C of HTT and proceeded further at 120 degrees C of HTT.

Automated summary

The influence of hydrothermal treatment (HTT) on hemicellulose in Japanese cedar was studied using low temperatures (95°C and 120°C) for kiln drying. Although there were slight changes in the chemical structure of hemicellulose, the major chemical components and their quantities only showed minimal differences. However, the molecular chain-length composition of hemicellulose decreased significantly with an increase in HTT temperature, indicating degradation of the polymeric structure.