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Official Journal of the Japan Wood Research Society

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Extractives relating to heartwood color changes in sugi (Cryptomeria japonica) by a combination of smoke-heating and UV radiation exposure

Abstract

 Sugi green logs with red or black heartwood were smoke-heated, and the changes in the color of the heartwood after ultraviolet (UV) (λ = 365 nm) radiation exposure were then observed. After UV radiation exposure, the redness and yellowness increased in both the red and black heartwoods, whereas the brightness decreased. In the black heartwood, the resulting color turned from yellowish white to reddish brown. Reddening in black heartwood after exposure to a combination of smoke heating and UV radiation is thought to be due to a decrease in brightness and an increase in both redness and yellowness. However, the degree of change in heartwood color by UV radiation exposure was not greatly affected by smoke-heating treatments of various lengths. When methanol extracts were fractionated and exposed to UV radiation, the yellowness increased in the n-hexane-soluble portion and the redness increased in the acetone-soluble fractions from the n-hexane-insoluble portion. These results suggest that the n-hexane-soluble fraction contains the substances that allow heartwood color to change to yellow after UV radiation exposure, and the acetone-soluble-fraction from the n-hexane-insoluble portion contains the substances that allow it to change to red.

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Correspondence to N. Yoshizawa.

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Received: November 14, 2001 / Accepted: June 3, 2002

Acknowledgment This research was supported in part by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science.

This study was presented in part at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001

Correspondence to:N. Yoshizawa

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Ishiguri, F., Maruyama, S., Takahashi, K. et al. Extractives relating to heartwood color changes in sugi (Cryptomeria japonica) by a combination of smoke-heating and UV radiation exposure. J Wood Sci 49, 135–139 (2003). https://doi.org/10.1007/s100860300021

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  • DOI: https://doi.org/10.1007/s100860300021