Evaluation of the Process of Steaming Beech Sapwood and False Heartwood with Saturated Water Steam in Terms of Acidity Changes and Color Wood
2025
Michal Dudiak
The paper presents changes in the color and acidity of beech wood with false heartwood in the process of pressure steaming at the temperature interval t = 105 °:C and 125 °:C during &tau: = 6 to 24 h. The light white-gray color of sapwood with a yellow tint changes to pale pink and red-brown to brown-red color during the steaming process. The color of beech wood with false heartwood changed to brown-gray color shades during 24 h of steaming with saturated water steam. From the measured data, as well as the visual evaluation of the color of the wood, I can conclude that, in the process of steaming beech wood with false heartwood, we can achieve color unification between false heartwood and sapwood in mode at temperature t = 105 °:C for time &tau: = 18 h and in mode at temperature t = 125 °:C for time &tau: = 12 h. Due to the influence of hemicellulose hydrolysis, the acidity of beech wood changes in the process of steaming. The decrease in acidity of beech wood in the temperature interval t = 105&ndash:125 °:C and time &tau: = 6&ndash:24 h is in the range of values pHsapwood = 5.2 to 3.6 and pHfalse heartwood = 5.0 to 3.9. The relationship between the total color difference ∆:E and the acidity change in beech sapwood and false heartwood is expressed by a second-degree polynomial function. The above mathematical relations represent a useful tool for evaluating the achieved color shade before further technological processing.
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