Pengukuran Kadar Ekstraktif dan Sifat Warna pada Kayu Teras Jati Doreng (Tectona grandis)
Abstract: Teak (Tectona
grandis L.f) in certain areas of Java usually has black streaked heartwood or
has been known as "doreng". In general, the color of wood is related
to the kinds and amounts of extractives, therefore, black streak that appeared
on the heartwood was studied by means of color measurements and the
determination of extractive content. The study was made with 13 trees of black
streaked heartwood and 5 trees of normal heartwood. The wood powder (40-60
mesh) was extracted successively with ethanol-benzene (1:2, v/v) for 8 h and
hot water for 3 h. The used system of color measurements was CIEL*a*b* which
represents brightness, redness and yellowness. The discolored wood was
contained substantially more ethanol-benzene soluble extractive content (12 -
22%) than did the normal heartwood (7 - 11%). The yield differences of
hot-water soluble extracts were not as pronounced. Beside the brightness (L*),
the differences in redness (a*) and yellowness (b*) between the normal (L* =
51-611, a* = 4 to 7, b* = 24 to 28) and black streaked heartwood (L* = 42-51,
a* = 6 to 9, b* = 20 to 25) before the extraction, were notable. The total
color differences ( E*) before and after extractions, however, were not
significantly differed between the discolored ( E* = 6 to 13) and normal
heartwood ( E* = 5 to 11) parts. Correlation analysis revealed strong
correlations between ethanol-benzene soluble extractive content with L* (r =
-0.97) and b* (r = -0.94). The hot-water soluble extract was moderately
correlated with a* (r = 0.54) and the difference in redness ( a*) before and
after extractions (r = 0.75).
Keywords: Tectona grandis,
black streak, doreng, extractives, color properties
Penulis: Ganis Lukmandaru
Kode Jurnal: jpkehutanandd090007
